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Subject[PATCH 1/2] staging: fix zcache building
Date
zcache is only building tmem.c and not building zcache.c. To keep the
module name, zcache.c must be renamed if symbols from tmem.c are to
remain unexported.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
---
drivers/staging/zcache/Makefile | 2 +-
drivers/staging/zcache/zcache-main.c | 1996 ++++++++++++++++++++++++++++++++++
drivers/staging/zcache/zcache.c | 1996 ----------------------------------
3 files changed, 1997 insertions(+), 1997 deletions(-)
create mode 100644 drivers/staging/zcache/zcache-main.c
delete mode 100644 drivers/staging/zcache/zcache.c
diff --git a/drivers/staging/zcache/Makefile b/drivers/staging/zcache/Makefile
index f5ec64f..60daa27 100644
--- a/drivers/staging/zcache/Makefile
+++ b/drivers/staging/zcache/Makefile
@@ -1,3 +1,3 @@
-zcache-y := tmem.o
+zcache-y := zcache-main.o tmem.o

obj-$(CONFIG_ZCACHE) += zcache.o
diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
new file mode 100644
index 0000000..65a81a0
--- /dev/null
+++ b/drivers/staging/zcache/zcache-main.c
@@ -0,0 +1,1996 @@
+/*
+ * zcache.c
+ *
+ * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
+ * Copyright (c) 2010,2011, Nitin Gupta
+ *
+ * Zcache provides an in-kernel "host implementation" for transcendent memory
+ * and, thus indirectly, for cleancache and frontswap. Zcache includes two
+ * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
+ * 1) "compression buddies" ("zbud") is used for ephemeral pages
+ * 2) xvmalloc is used for persistent pages.
+ * Xvmalloc (based on the TLSF allocator) has very low fragmentation
+ * so maximizes space efficiency, while zbud allows pairs (and potentially,
+ * in the future, more than a pair of) compressed pages to be closely linked
+ * so that reclaiming can be done via the kernel's physical-page-oriented
+ * "shrinker" interface.
+ *
+ * [1] For a definition of page-accessible memory (aka PAM), see:
+ * http://marc.info/?l=linux-mm&m=127811271605009
+ */
+
+#include <linux/cpu.h>
+#include <linux/highmem.h>
+#include <linux/list.h>
+#include <linux/lzo.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include "tmem.h"
+
+#include "../zram/xvmalloc.h" /* if built in drivers/staging */
+
+#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
+#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
+#endif
+#ifdef CONFIG_CLEANCACHE
+#include <linux/cleancache.h>
+#endif
+#ifdef CONFIG_FRONTSWAP
+#include <linux/frontswap.h>
+#endif
+
+#if 0
+/* this is more aggressive but may cause other problems? */
+#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
+#else
+#define ZCACHE_GFP_MASK \
+ (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
+#endif
+
+#define MAX_POOLS_PER_CLIENT 16
+
+#define MAX_CLIENTS 16
+#define LOCAL_CLIENT ((uint16_t)-1)
+struct zcache_client {
+ struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
+ struct xv_pool *xvpool;
+ bool allocated;
+ atomic_t refcount;
+};
+
+static struct zcache_client zcache_host;
+static struct zcache_client zcache_clients[MAX_CLIENTS];
+
+static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
+{
+ BUG_ON(cli == NULL);
+ if (cli == &zcache_host)
+ return LOCAL_CLIENT;
+ return cli - &zcache_clients[0];
+}
+
+static inline bool is_local_client(struct zcache_client *cli)
+{
+ return cli == &zcache_host;
+}
+
+/**********
+ * Compression buddies ("zbud") provides for packing two (or, possibly
+ * in the future, more) compressed ephemeral pages into a single "raw"
+ * (physical) page and tracking them with data structures so that
+ * the raw pages can be easily reclaimed.
+ *
+ * A zbud page ("zbpg") is an aligned page containing a list_head,
+ * a lock, and two "zbud headers". The remainder of the physical
+ * page is divided up into aligned 64-byte "chunks" which contain
+ * the compressed data for zero, one, or two zbuds. Each zbpg
+ * resides on: (1) an "unused list" if it has no zbuds; (2) a
+ * "buddied" list if it is fully populated with two zbuds; or
+ * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
+ * the one unbuddied zbud uses. The data inside a zbpg cannot be
+ * read or written unless the zbpg's lock is held.
+ */
+
+#define ZBH_SENTINEL 0x43214321
+#define ZBPG_SENTINEL 0xdeadbeef
+
+#define ZBUD_MAX_BUDS 2
+
+struct zbud_hdr {
+ uint16_t client_id;
+ uint16_t pool_id;
+ struct tmem_oid oid;
+ uint32_t index;
+ uint16_t size; /* compressed size in bytes, zero means unused */
+ DECL_SENTINEL
+};
+
+struct zbud_page {
+ struct list_head bud_list;
+ spinlock_t lock;
+ struct zbud_hdr buddy[ZBUD_MAX_BUDS];
+ DECL_SENTINEL
+ /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
+};
+
+#define CHUNK_SHIFT 6
+#define CHUNK_SIZE (1 << CHUNK_SHIFT)
+#define CHUNK_MASK (~(CHUNK_SIZE-1))
+#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
+ CHUNK_MASK) >> CHUNK_SHIFT)
+#define MAX_CHUNK (NCHUNKS-1)
+
+static struct {
+ struct list_head list;
+ unsigned count;
+} zbud_unbuddied[NCHUNKS];
+/* list N contains pages with N chunks USED and NCHUNKS-N unused */
+/* element 0 is never used but optimizing that isn't worth it */
+static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
+
+struct list_head zbud_buddied_list;
+static unsigned long zcache_zbud_buddied_count;
+
+/* protects the buddied list and all unbuddied lists */
+static DEFINE_SPINLOCK(zbud_budlists_spinlock);
+
+static LIST_HEAD(zbpg_unused_list);
+static unsigned long zcache_zbpg_unused_list_count;
+
+/* protects the unused page list */
+static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
+
+static atomic_t zcache_zbud_curr_raw_pages;
+static atomic_t zcache_zbud_curr_zpages;
+static unsigned long zcache_zbud_curr_zbytes;
+static unsigned long zcache_zbud_cumul_zpages;
+static unsigned long zcache_zbud_cumul_zbytes;
+static unsigned long zcache_compress_poor;
+static unsigned long zcache_mean_compress_poor;
+
+/* forward references */
+static void *zcache_get_free_page(void);
+static void zcache_free_page(void *p);
+
+/*
+ * zbud helper functions
+ */
+
+static inline unsigned zbud_max_buddy_size(void)
+{
+ return MAX_CHUNK << CHUNK_SHIFT;
+}
+
+static inline unsigned zbud_size_to_chunks(unsigned size)
+{
+ BUG_ON(size == 0 || size > zbud_max_buddy_size());
+ return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
+}
+
+static inline int zbud_budnum(struct zbud_hdr *zh)
+{
+ unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
+ struct zbud_page *zbpg = NULL;
+ unsigned budnum = -1U;
+ int i;
+
+ for (i = 0; i < ZBUD_MAX_BUDS; i++)
+ if (offset == offsetof(typeof(*zbpg), buddy[i])) {
+ budnum = i;
+ break;
+ }
+ BUG_ON(budnum == -1U);
+ return budnum;
+}
+
+static char *zbud_data(struct zbud_hdr *zh, unsigned size)
+{
+ struct zbud_page *zbpg;
+ char *p;
+ unsigned budnum;
+
+ ASSERT_SENTINEL(zh, ZBH);
+ budnum = zbud_budnum(zh);
+ BUG_ON(size == 0 || size > zbud_max_buddy_size());
+ zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
+ ASSERT_SPINLOCK(&zbpg->lock);
+ p = (char *)zbpg;
+ if (budnum == 0)
+ p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
+ CHUNK_MASK);
+ else if (budnum == 1)
+ p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
+ return p;
+}
+
+/*
+ * zbud raw page management
+ */
+
+static struct zbud_page *zbud_alloc_raw_page(void)
+{
+ struct zbud_page *zbpg = NULL;
+ struct zbud_hdr *zh0, *zh1;
+ bool recycled = 0;
+
+ /* if any pages on the zbpg list, use one */
+ spin_lock(&zbpg_unused_list_spinlock);
+ if (!list_empty(&zbpg_unused_list)) {
+ zbpg = list_first_entry(&zbpg_unused_list,
+ struct zbud_page, bud_list);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbpg_unused_list_count--;
+ recycled = 1;
+ }
+ spin_unlock(&zbpg_unused_list_spinlock);
+ if (zbpg == NULL)
+ /* none on zbpg list, try to get a kernel page */
+ zbpg = zcache_get_free_page();
+ if (likely(zbpg != NULL)) {
+ INIT_LIST_HEAD(&zbpg->bud_list);
+ zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
+ spin_lock_init(&zbpg->lock);
+ if (recycled) {
+ ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
+ SET_SENTINEL(zbpg, ZBPG);
+ BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
+ BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
+ } else {
+ atomic_inc(&zcache_zbud_curr_raw_pages);
+ INIT_LIST_HEAD(&zbpg->bud_list);
+ SET_SENTINEL(zbpg, ZBPG);
+ zh0->size = 0; zh1->size = 0;
+ tmem_oid_set_invalid(&zh0->oid);
+ tmem_oid_set_invalid(&zh1->oid);
+ }
+ }
+ return zbpg;
+}
+
+static void zbud_free_raw_page(struct zbud_page *zbpg)
+{
+ struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
+
+ ASSERT_SENTINEL(zbpg, ZBPG);
+ BUG_ON(!list_empty(&zbpg->bud_list));
+ ASSERT_SPINLOCK(&zbpg->lock);
+ BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
+ BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
+ INVERT_SENTINEL(zbpg, ZBPG);
+ spin_unlock(&zbpg->lock);
+ spin_lock(&zbpg_unused_list_spinlock);
+ list_add(&zbpg->bud_list, &zbpg_unused_list);
+ zcache_zbpg_unused_list_count++;
+ spin_unlock(&zbpg_unused_list_spinlock);
+}
+
+/*
+ * core zbud handling routines
+ */
+
+static unsigned zbud_free(struct zbud_hdr *zh)
+{
+ unsigned size;
+
+ ASSERT_SENTINEL(zh, ZBH);
+ BUG_ON(!tmem_oid_valid(&zh->oid));
+ size = zh->size;
+ BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
+ zh->size = 0;
+ tmem_oid_set_invalid(&zh->oid);
+ INVERT_SENTINEL(zh, ZBH);
+ zcache_zbud_curr_zbytes -= size;
+ atomic_dec(&zcache_zbud_curr_zpages);
+ return size;
+}
+
+static void zbud_free_and_delist(struct zbud_hdr *zh)
+{
+ unsigned chunks;
+ struct zbud_hdr *zh_other;
+ unsigned budnum = zbud_budnum(zh), size;
+ struct zbud_page *zbpg =
+ container_of(zh, struct zbud_page, buddy[budnum]);
+
+ spin_lock(&zbpg->lock);
+ if (list_empty(&zbpg->bud_list)) {
+ /* ignore zombie page... see zbud_evict_pages() */
+ spin_unlock(&zbpg->lock);
+ return;
+ }
+ size = zbud_free(zh);
+ ASSERT_SPINLOCK(&zbpg->lock);
+ zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
+ if (zh_other->size == 0) { /* was unbuddied: unlist and free */
+ chunks = zbud_size_to_chunks(size) ;
+ spin_lock(&zbud_budlists_spinlock);
+ BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[chunks].count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zbud_free_raw_page(zbpg);
+ } else { /* was buddied: move remaining buddy to unbuddied list */
+ chunks = zbud_size_to_chunks(zh_other->size) ;
+ spin_lock(&zbud_budlists_spinlock);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbud_buddied_count--;
+ list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
+ zbud_unbuddied[chunks].count++;
+ spin_unlock(&zbud_budlists_spinlock);
+ spin_unlock(&zbpg->lock);
+ }
+}
+
+static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
+ struct tmem_oid *oid,
+ uint32_t index, struct page *page,
+ void *cdata, unsigned size)
+{
+ struct zbud_hdr *zh0, *zh1, *zh = NULL;
+ struct zbud_page *zbpg = NULL, *ztmp;
+ unsigned nchunks;
+ char *to;
+ int i, found_good_buddy = 0;
+
+ nchunks = zbud_size_to_chunks(size) ;
+ for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
+ spin_lock(&zbud_budlists_spinlock);
+ if (!list_empty(&zbud_unbuddied[i].list)) {
+ list_for_each_entry_safe(zbpg, ztmp,
+ &zbud_unbuddied[i].list, bud_list) {
+ if (spin_trylock(&zbpg->lock)) {
+ found_good_buddy = i;
+ goto found_unbuddied;
+ }
+ }
+ }
+ spin_unlock(&zbud_budlists_spinlock);
+ }
+ /* didn't find a good buddy, try allocating a new page */
+ zbpg = zbud_alloc_raw_page();
+ if (unlikely(zbpg == NULL))
+ goto out;
+ /* ok, have a page, now compress the data before taking locks */
+ spin_lock(&zbpg->lock);
+ spin_lock(&zbud_budlists_spinlock);
+ list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
+ zbud_unbuddied[nchunks].count++;
+ zh = &zbpg->buddy[0];
+ goto init_zh;
+
+found_unbuddied:
+ ASSERT_SPINLOCK(&zbpg->lock);
+ zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
+ BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
+ if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
+ ASSERT_SENTINEL(zh0, ZBH);
+ zh = zh1;
+ } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
+ ASSERT_SENTINEL(zh1, ZBH);
+ zh = zh0;
+ } else
+ BUG();
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[found_good_buddy].count--;
+ list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
+ zcache_zbud_buddied_count++;
+
+init_zh:
+ SET_SENTINEL(zh, ZBH);
+ zh->size = size;
+ zh->index = index;
+ zh->oid = *oid;
+ zh->pool_id = pool_id;
+ zh->client_id = client_id;
+ /* can wait to copy the data until the list locks are dropped */
+ spin_unlock(&zbud_budlists_spinlock);
+
+ to = zbud_data(zh, size);
+ memcpy(to, cdata, size);
+ spin_unlock(&zbpg->lock);
+ zbud_cumul_chunk_counts[nchunks]++;
+ atomic_inc(&zcache_zbud_curr_zpages);
+ zcache_zbud_cumul_zpages++;
+ zcache_zbud_curr_zbytes += size;
+ zcache_zbud_cumul_zbytes += size;
+out:
+ return zh;
+}
+
+static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
+{
+ struct zbud_page *zbpg;
+ unsigned budnum = zbud_budnum(zh);
+ size_t out_len = PAGE_SIZE;
+ char *to_va, *from_va;
+ unsigned size;
+ int ret = 0;
+
+ zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
+ spin_lock(&zbpg->lock);
+ if (list_empty(&zbpg->bud_list)) {
+ /* ignore zombie page... see zbud_evict_pages() */
+ ret = -EINVAL;
+ goto out;
+ }
+ ASSERT_SENTINEL(zh, ZBH);
+ BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
+ to_va = kmap_atomic(page, KM_USER0);
+ size = zh->size;
+ from_va = zbud_data(zh, size);
+ ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
+ BUG_ON(ret != LZO_E_OK);
+ BUG_ON(out_len != PAGE_SIZE);
+ kunmap_atomic(to_va, KM_USER0);
+out:
+ spin_unlock(&zbpg->lock);
+ return ret;
+}
+
+/*
+ * The following routines handle shrinking of ephemeral pages by evicting
+ * pages "least valuable" first.
+ */
+
+static unsigned long zcache_evicted_raw_pages;
+static unsigned long zcache_evicted_buddied_pages;
+static unsigned long zcache_evicted_unbuddied_pages;
+
+static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
+ uint16_t poolid);
+static void zcache_put_pool(struct tmem_pool *pool);
+
+/*
+ * Flush and free all zbuds in a zbpg, then free the pageframe
+ */
+static void zbud_evict_zbpg(struct zbud_page *zbpg)
+{
+ struct zbud_hdr *zh;
+ int i, j;
+ uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
+ uint32_t index[ZBUD_MAX_BUDS];
+ struct tmem_oid oid[ZBUD_MAX_BUDS];
+ struct tmem_pool *pool;
+
+ ASSERT_SPINLOCK(&zbpg->lock);
+ BUG_ON(!list_empty(&zbpg->bud_list));
+ for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
+ zh = &zbpg->buddy[i];
+ if (zh->size) {
+ client_id[j] = zh->client_id;
+ pool_id[j] = zh->pool_id;
+ oid[j] = zh->oid;
+ index[j] = zh->index;
+ j++;
+ zbud_free(zh);
+ }
+ }
+ spin_unlock(&zbpg->lock);
+ for (i = 0; i < j; i++) {
+ pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
+ if (pool != NULL) {
+ tmem_flush_page(pool, &oid[i], index[i]);
+ zcache_put_pool(pool);
+ }
+ }
+ ASSERT_SENTINEL(zbpg, ZBPG);
+ spin_lock(&zbpg->lock);
+ zbud_free_raw_page(zbpg);
+}
+
+/*
+ * Free nr pages. This code is funky because we want to hold the locks
+ * protecting various lists for as short a time as possible, and in some
+ * circumstances the list may change asynchronously when the list lock is
+ * not held. In some cases we also trylock not only to avoid waiting on a
+ * page in use by another cpu, but also to avoid potential deadlock due to
+ * lock inversion.
+ */
+static void zbud_evict_pages(int nr)
+{
+ struct zbud_page *zbpg;
+ int i;
+
+ /* first try freeing any pages on unused list */
+retry_unused_list:
+ spin_lock_bh(&zbpg_unused_list_spinlock);
+ if (!list_empty(&zbpg_unused_list)) {
+ /* can't walk list here, since it may change when unlocked */
+ zbpg = list_first_entry(&zbpg_unused_list,
+ struct zbud_page, bud_list);
+ list_del_init(&zbpg->bud_list);
+ zcache_zbpg_unused_list_count--;
+ atomic_dec(&zcache_zbud_curr_raw_pages);
+ spin_unlock_bh(&zbpg_unused_list_spinlock);
+ zcache_free_page(zbpg);
+ zcache_evicted_raw_pages++;
+ if (--nr <= 0)
+ goto out;
+ goto retry_unused_list;
+ }
+ spin_unlock_bh(&zbpg_unused_list_spinlock);
+
+ /* now try freeing unbuddied pages, starting with least space avail */
+ for (i = 0; i < MAX_CHUNK; i++) {
+retry_unbud_list_i:
+ spin_lock_bh(&zbud_budlists_spinlock);
+ if (list_empty(&zbud_unbuddied[i].list)) {
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ continue;
+ }
+ list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
+ if (unlikely(!spin_trylock(&zbpg->lock)))
+ continue;
+ list_del_init(&zbpg->bud_list);
+ zbud_unbuddied[i].count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zcache_evicted_unbuddied_pages++;
+ /* want budlists unlocked when doing zbpg eviction */
+ zbud_evict_zbpg(zbpg);
+ local_bh_enable();
+ if (--nr <= 0)
+ goto out;
+ goto retry_unbud_list_i;
+ }
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ }
+
+ /* as a last resort, free buddied pages */
+retry_bud_list:
+ spin_lock_bh(&zbud_budlists_spinlock);
+ if (list_empty(&zbud_buddied_list)) {
+ spin_unlock_bh(&zbud_budlists_spinlock);
+ goto out;
+ }
+ list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
+ if (unlikely(!spin_trylock(&zbpg->lock)))
+ continue;
+ list_del_init(&zbpg->bud_list);
+ zcache_zbud_buddied_count--;
+ spin_unlock(&zbud_budlists_spinlock);
+ zcache_evicted_buddied_pages++;
+ /* want budlists unlocked when doing zbpg eviction */
+ zbud_evict_zbpg(zbpg);
+ local_bh_enable();
+ if (--nr <= 0)
+ goto out;
+ goto retry_bud_list;
+ }
+ spin_unlock_bh(&zbud_budlists_spinlock);
+out:
+ return;
+}
+
+static void zbud_init(void)
+{
+ int i;
+
+ INIT_LIST_HEAD(&zbud_buddied_list);
+ zcache_zbud_buddied_count = 0;
+ for (i = 0; i < NCHUNKS; i++) {
+ INIT_LIST_HEAD(&zbud_unbuddied[i].list);
+ zbud_unbuddied[i].count = 0;
+ }
+}
+
+#ifdef CONFIG_SYSFS
+/*
+ * These sysfs routines show a nice distribution of how many zbpg's are
+ * currently (and have ever been placed) in each unbuddied list. It's fun
+ * to watch but can probably go away before final merge.
+ */
+static int zbud_show_unbuddied_list_counts(char *buf)
+{
+ int i;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++)
+ p += sprintf(p, "%u ", zbud_unbuddied[i].count);
+ return p - buf;
+}
+
+static int zbud_show_cumul_chunk_counts(char *buf)
+{
+ unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
+ unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
+ unsigned long total_chunks_lte_42 = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
+ chunks += zbud_cumul_chunk_counts[i];
+ total_chunks += zbud_cumul_chunk_counts[i];
+ sum_total_chunks += i * zbud_cumul_chunk_counts[i];
+ if (i == 21)
+ total_chunks_lte_21 = total_chunks;
+ if (i == 32)
+ total_chunks_lte_32 = total_chunks;
+ if (i == 42)
+ total_chunks_lte_42 = total_chunks;
+ }
+ p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
+ total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+#endif
+
+/**********
+ * This "zv" PAM implementation combines the TLSF-based xvMalloc
+ * with lzo1x compression to maximize the amount of data that can
+ * be packed into a physical page.
+ *
+ * Zv represents a PAM page with the index and object (plus a "size" value
+ * necessary for decompression) immediately preceding the compressed data.
+ */
+
+#define ZVH_SENTINEL 0x43214321
+
+struct zv_hdr {
+ uint32_t pool_id;
+ struct tmem_oid oid;
+ uint32_t index;
+ DECL_SENTINEL
+};
+
+/* rudimentary policy limits */
+/* total number of persistent pages may not exceed this percentage */
+static unsigned int zv_page_count_policy_percent = 75;
+/*
+ * byte count defining poor compression; pages with greater zsize will be
+ * rejected
+ */
+static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
+/*
+ * byte count defining poor *mean* compression; pages with greater zsize
+ * will be rejected until sufficient better-compressed pages are accepted
+ * driving the man below this threshold
+ */
+static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
+
+static unsigned long zv_curr_dist_counts[NCHUNKS];
+static unsigned long zv_cumul_dist_counts[NCHUNKS];
+
+static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
+ struct tmem_oid *oid, uint32_t index,
+ void *cdata, unsigned clen)
+{
+ struct page *page;
+ struct zv_hdr *zv = NULL;
+ uint32_t offset;
+ int alloc_size = clen + sizeof(struct zv_hdr);
+ int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
+ int ret;
+
+ BUG_ON(!irqs_disabled());
+ BUG_ON(chunks >= NCHUNKS);
+ ret = xv_malloc(xvpool, alloc_size,
+ &page, &offset, ZCACHE_GFP_MASK);
+ if (unlikely(ret))
+ goto out;
+ zv_curr_dist_counts[chunks]++;
+ zv_cumul_dist_counts[chunks]++;
+ zv = kmap_atomic(page, KM_USER0) + offset;
+ zv->index = index;
+ zv->oid = *oid;
+ zv->pool_id = pool_id;
+ SET_SENTINEL(zv, ZVH);
+ memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
+ kunmap_atomic(zv, KM_USER0);
+out:
+ return zv;
+}
+
+static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
+{
+ unsigned long flags;
+ struct page *page;
+ uint32_t offset;
+ uint16_t size = xv_get_object_size(zv);
+ int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
+
+ ASSERT_SENTINEL(zv, ZVH);
+ BUG_ON(chunks >= NCHUNKS);
+ zv_curr_dist_counts[chunks]--;
+ size -= sizeof(*zv);
+ BUG_ON(size == 0);
+ INVERT_SENTINEL(zv, ZVH);
+ page = virt_to_page(zv);
+ offset = (unsigned long)zv & ~PAGE_MASK;
+ local_irq_save(flags);
+ xv_free(xvpool, page, offset);
+ local_irq_restore(flags);
+}
+
+static void zv_decompress(struct page *page, struct zv_hdr *zv)
+{
+ size_t clen = PAGE_SIZE;
+ char *to_va;
+ unsigned size;
+ int ret;
+
+ ASSERT_SENTINEL(zv, ZVH);
+ size = xv_get_object_size(zv) - sizeof(*zv);
+ BUG_ON(size == 0);
+ to_va = kmap_atomic(page, KM_USER0);
+ ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
+ size, to_va, &clen);
+ kunmap_atomic(to_va, KM_USER0);
+ BUG_ON(ret != LZO_E_OK);
+ BUG_ON(clen != PAGE_SIZE);
+}
+
+#ifdef CONFIG_SYSFS
+/*
+ * show a distribution of compression stats for zv pages.
+ */
+
+static int zv_curr_dist_counts_show(char *buf)
+{
+ unsigned long i, n, chunks = 0, sum_total_chunks = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ n = zv_curr_dist_counts[i];
+ p += sprintf(p, "%lu ", n);
+ chunks += n;
+ sum_total_chunks += i * n;
+ }
+ p += sprintf(p, "mean:%lu\n",
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+
+static int zv_cumul_dist_counts_show(char *buf)
+{
+ unsigned long i, n, chunks = 0, sum_total_chunks = 0;
+ char *p = buf;
+
+ for (i = 0; i < NCHUNKS; i++) {
+ n = zv_cumul_dist_counts[i];
+ p += sprintf(p, "%lu ", n);
+ chunks += n;
+ sum_total_chunks += i * n;
+ }
+ p += sprintf(p, "mean:%lu\n",
+ chunks == 0 ? 0 : sum_total_chunks / chunks);
+ return p - buf;
+}
+
+/*
+ * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
+ * pages that don't compress to less than this value (including metadata
+ * overhead) to be rejected. We don't allow the value to get too close
+ * to PAGE_SIZE.
+ */
+static ssize_t zv_max_zsize_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_max_zsize);
+}
+
+static ssize_t zv_max_zsize_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
+ return -EINVAL;
+ zv_max_zsize = val;
+ return count;
+}
+
+/*
+ * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
+ * pages that don't compress to less than this value (including metadata
+ * overhead) to be rejected UNLESS the mean compression is also smaller
+ * than this value. In other words, we are load-balancing-by-zsize the
+ * accepted pages. Again, we don't allow the value to get too close
+ * to PAGE_SIZE.
+ */
+static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_max_mean_zsize);
+}
+
+static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
+ return -EINVAL;
+ zv_max_mean_zsize = val;
+ return count;
+}
+
+/*
+ * setting zv_page_count_policy_percent via sysfs sets an upper bound of
+ * persistent (e.g. swap) pages that will be retained according to:
+ * (zv_page_count_policy_percent * totalram_pages) / 100)
+ * when that limit is reached, further puts will be rejected (until
+ * some pages have been flushed). Note that, due to compression,
+ * this number may exceed 100; it defaults to 75 and we set an
+ * arbitary limit of 150. A poor choice will almost certainly result
+ * in OOM's, so this value should only be changed prudently.
+ */
+static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", zv_page_count_policy_percent);
+}
+
+static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned long val;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ err = strict_strtoul(buf, 10, &val);
+ if (err || (val == 0) || (val > 150))
+ return -EINVAL;
+ zv_page_count_policy_percent = val;
+ return count;
+}
+
+static struct kobj_attribute zcache_zv_max_zsize_attr = {
+ .attr = { .name = "zv_max_zsize", .mode = 0644 },
+ .show = zv_max_zsize_show,
+ .store = zv_max_zsize_store,
+};
+
+static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
+ .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
+ .show = zv_max_mean_zsize_show,
+ .store = zv_max_mean_zsize_store,
+};
+
+static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
+ .attr = { .name = "zv_page_count_policy_percent",
+ .mode = 0644 },
+ .show = zv_page_count_policy_percent_show,
+ .store = zv_page_count_policy_percent_store,
+};
+#endif
+
+/*
+ * zcache core code starts here
+ */
+
+/* useful stats not collected by cleancache or frontswap */
+static unsigned long zcache_flush_total;
+static unsigned long zcache_flush_found;
+static unsigned long zcache_flobj_total;
+static unsigned long zcache_flobj_found;
+static unsigned long zcache_failed_eph_puts;
+static unsigned long zcache_failed_pers_puts;
+
+/*
+ * Tmem operations assume the poolid implies the invoking client.
+ * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
+ * RAMster has each client numbered by cluster node, and a KVM version
+ * of zcache would have one client per guest and each client might
+ * have a poolid==N.
+ */
+static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else {
+ if (cli_id >= MAX_CLIENTS)
+ goto out;
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ }
+ if (poolid < MAX_POOLS_PER_CLIENT) {
+ pool = cli->tmem_pools[poolid];
+ if (pool != NULL)
+ atomic_inc(&pool->refcount);
+ }
+out:
+ return pool;
+}
+
+static void zcache_put_pool(struct tmem_pool *pool)
+{
+ struct zcache_client *cli = NULL;
+
+ if (pool == NULL)
+ BUG();
+ cli = pool->client;
+ atomic_dec(&pool->refcount);
+ atomic_dec(&cli->refcount);
+}
+
+int zcache_new_client(uint16_t cli_id)
+{
+ struct zcache_client *cli = NULL;
+ int ret = -1;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ if (cli->allocated)
+ goto out;
+ cli->allocated = 1;
+#ifdef CONFIG_FRONTSWAP
+ cli->xvpool = xv_create_pool();
+ if (cli->xvpool == NULL)
+ goto out;
+#endif
+ ret = 0;
+out:
+ return ret;
+}
+
+/* counters for debugging */
+static unsigned long zcache_failed_get_free_pages;
+static unsigned long zcache_failed_alloc;
+static unsigned long zcache_put_to_flush;
+static unsigned long zcache_aborted_preload;
+static unsigned long zcache_aborted_shrink;
+
+/*
+ * Ensure that memory allocation requests in zcache don't result
+ * in direct reclaim requests via the shrinker, which would cause
+ * an infinite loop. Maybe a GFP flag would be better?
+ */
+static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
+
+/*
+ * for now, used named slabs so can easily track usage; later can
+ * either just use kmalloc, or perhaps add a slab-like allocator
+ * to more carefully manage total memory utilization
+ */
+static struct kmem_cache *zcache_objnode_cache;
+static struct kmem_cache *zcache_obj_cache;
+static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_obj_count_max;
+static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_objnode_count_max;
+
+/*
+ * to avoid memory allocation recursion (e.g. due to direct reclaim), we
+ * preload all necessary data structures so the hostops callbacks never
+ * actually do a malloc
+ */
+struct zcache_preload {
+ void *page;
+ struct tmem_obj *obj;
+ int nr;
+ struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
+};
+static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
+
+static int zcache_do_preload(struct tmem_pool *pool)
+{
+ struct zcache_preload *kp;
+ struct tmem_objnode *objnode;
+ struct tmem_obj *obj;
+ void *page;
+ int ret = -ENOMEM;
+
+ if (unlikely(zcache_objnode_cache == NULL))
+ goto out;
+ if (unlikely(zcache_obj_cache == NULL))
+ goto out;
+ if (!spin_trylock(&zcache_direct_reclaim_lock)) {
+ zcache_aborted_preload++;
+ goto out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
+ preempt_enable_no_resched();
+ objnode = kmem_cache_alloc(zcache_objnode_cache,
+ ZCACHE_GFP_MASK);
+ if (unlikely(objnode == NULL)) {
+ zcache_failed_alloc++;
+ goto unlock_out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->nr < ARRAY_SIZE(kp->objnodes))
+ kp->objnodes[kp->nr++] = objnode;
+ else
+ kmem_cache_free(zcache_objnode_cache, objnode);
+ }
+ preempt_enable_no_resched();
+ obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
+ if (unlikely(obj == NULL)) {
+ zcache_failed_alloc++;
+ goto unlock_out;
+ }
+ page = (void *)__get_free_page(ZCACHE_GFP_MASK);
+ if (unlikely(page == NULL)) {
+ zcache_failed_get_free_pages++;
+ kmem_cache_free(zcache_obj_cache, obj);
+ goto unlock_out;
+ }
+ preempt_disable();
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->obj == NULL)
+ kp->obj = obj;
+ else
+ kmem_cache_free(zcache_obj_cache, obj);
+ if (kp->page == NULL)
+ kp->page = page;
+ else
+ free_page((unsigned long)page);
+ ret = 0;
+unlock_out:
+ spin_unlock(&zcache_direct_reclaim_lock);
+out:
+ return ret;
+}
+
+static void *zcache_get_free_page(void)
+{
+ struct zcache_preload *kp;
+ void *page;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ page = kp->page;
+ BUG_ON(page == NULL);
+ kp->page = NULL;
+ return page;
+}
+
+static void zcache_free_page(void *p)
+{
+ free_page((unsigned long)p);
+}
+
+/*
+ * zcache implementation for tmem host ops
+ */
+
+static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
+{
+ struct tmem_objnode *objnode = NULL;
+ unsigned long count;
+ struct zcache_preload *kp;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ if (kp->nr <= 0)
+ goto out;
+ objnode = kp->objnodes[kp->nr - 1];
+ BUG_ON(objnode == NULL);
+ kp->objnodes[kp->nr - 1] = NULL;
+ kp->nr--;
+ count = atomic_inc_return(&zcache_curr_objnode_count);
+ if (count > zcache_curr_objnode_count_max)
+ zcache_curr_objnode_count_max = count;
+out:
+ return objnode;
+}
+
+static void zcache_objnode_free(struct tmem_objnode *objnode,
+ struct tmem_pool *pool)
+{
+ atomic_dec(&zcache_curr_objnode_count);
+ BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
+ kmem_cache_free(zcache_objnode_cache, objnode);
+}
+
+static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
+{
+ struct tmem_obj *obj = NULL;
+ unsigned long count;
+ struct zcache_preload *kp;
+
+ kp = &__get_cpu_var(zcache_preloads);
+ obj = kp->obj;
+ BUG_ON(obj == NULL);
+ kp->obj = NULL;
+ count = atomic_inc_return(&zcache_curr_obj_count);
+ if (count > zcache_curr_obj_count_max)
+ zcache_curr_obj_count_max = count;
+ return obj;
+}
+
+static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
+{
+ atomic_dec(&zcache_curr_obj_count);
+ BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
+ kmem_cache_free(zcache_obj_cache, obj);
+}
+
+static struct tmem_hostops zcache_hostops = {
+ .obj_alloc = zcache_obj_alloc,
+ .obj_free = zcache_obj_free,
+ .objnode_alloc = zcache_objnode_alloc,
+ .objnode_free = zcache_objnode_free,
+};
+
+/*
+ * zcache implementations for PAM page descriptor ops
+ */
+
+static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_eph_pampd_count_max;
+static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
+static unsigned long zcache_curr_pers_pampd_count_max;
+
+/* forward reference */
+static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
+
+static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
+ struct tmem_pool *pool, struct tmem_oid *oid,
+ uint32_t index)
+{
+ void *pampd = NULL, *cdata;
+ size_t clen;
+ int ret;
+ unsigned long count;
+ struct page *page = virt_to_page(data);
+ struct zcache_client *cli = pool->client;
+ uint16_t client_id = get_client_id_from_client(cli);
+ unsigned long zv_mean_zsize;
+ unsigned long curr_pers_pampd_count;
+
+ if (eph) {
+ ret = zcache_compress(page, &cdata, &clen);
+ if (ret == 0)
+ goto out;
+ if (clen == 0 || clen > zbud_max_buddy_size()) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
+ index, page, cdata, clen);
+ if (pampd != NULL) {
+ count = atomic_inc_return(&zcache_curr_eph_pampd_count);
+ if (count > zcache_curr_eph_pampd_count_max)
+ zcache_curr_eph_pampd_count_max = count;
+ }
+ } else {
+ curr_pers_pampd_count =
+ atomic_read(&zcache_curr_pers_pampd_count);
+ if (curr_pers_pampd_count >
+ (zv_page_count_policy_percent * totalram_pages) / 100)
+ goto out;
+ ret = zcache_compress(page, &cdata, &clen);
+ if (ret == 0)
+ goto out;
+ /* reject if compression is too poor */
+ if (clen > zv_max_zsize) {
+ zcache_compress_poor++;
+ goto out;
+ }
+ /* reject if mean compression is too poor */
+ if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
+ zv_mean_zsize = xv_get_total_size_bytes(cli->xvpool) /
+ curr_pers_pampd_count;
+ if (zv_mean_zsize > zv_max_mean_zsize) {
+ zcache_mean_compress_poor++;
+ goto out;
+ }
+ }
+ pampd = (void *)zv_create(cli->xvpool, pool->pool_id,
+ oid, index, cdata, clen);
+ if (pampd == NULL)
+ goto out;
+ count = atomic_inc_return(&zcache_curr_pers_pampd_count);
+ if (count > zcache_curr_pers_pampd_count_max)
+ zcache_curr_pers_pampd_count_max = count;
+ }
+out:
+ return pampd;
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret = 0;
+
+ BUG_ON(is_ephemeral(pool));
+ zv_decompress(virt_to_page(data), pampd);
+ return ret;
+}
+
+/*
+ * fill the pageframe corresponding to the struct page with the data
+ * from the passed pampd
+ */
+static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
+ void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ int ret = 0;
+
+ BUG_ON(!is_ephemeral(pool));
+ zbud_decompress(virt_to_page(data), pampd);
+ zbud_free_and_delist((struct zbud_hdr *)pampd);
+ atomic_dec(&zcache_curr_eph_pampd_count);
+ return ret;
+}
+
+/*
+ * free the pampd and remove it from any zcache lists
+ * pampd must no longer be pointed to from any tmem data structures!
+ */
+static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
+ struct tmem_oid *oid, uint32_t index)
+{
+ struct zcache_client *cli = pool->client;
+
+ if (is_ephemeral(pool)) {
+ zbud_free_and_delist((struct zbud_hdr *)pampd);
+ atomic_dec(&zcache_curr_eph_pampd_count);
+ BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
+ } else {
+ zv_free(cli->xvpool, (struct zv_hdr *)pampd);
+ atomic_dec(&zcache_curr_pers_pampd_count);
+ BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
+ }
+}
+
+static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
+{
+}
+
+static void zcache_pampd_new_obj(struct tmem_obj *obj)
+{
+}
+
+static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
+{
+ return -1;
+}
+
+static bool zcache_pampd_is_remote(void *pampd)
+{
+ return 0;
+}
+
+static struct tmem_pamops zcache_pamops = {
+ .create = zcache_pampd_create,
+ .get_data = zcache_pampd_get_data,
+ .get_data_and_free = zcache_pampd_get_data_and_free,
+ .free = zcache_pampd_free,
+ .free_obj = zcache_pampd_free_obj,
+ .new_obj = zcache_pampd_new_obj,
+ .replace_in_obj = zcache_pampd_replace_in_obj,
+ .is_remote = zcache_pampd_is_remote,
+};
+
+/*
+ * zcache compression/decompression and related per-cpu stuff
+ */
+
+#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
+#define LZO_DSTMEM_PAGE_ORDER 1
+static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
+static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
+
+static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
+{
+ int ret = 0;
+ unsigned char *dmem = __get_cpu_var(zcache_dstmem);
+ unsigned char *wmem = __get_cpu_var(zcache_workmem);
+ char *from_va;
+
+ BUG_ON(!irqs_disabled());
+ if (unlikely(dmem == NULL || wmem == NULL))
+ goto out; /* no buffer, so can't compress */
+ from_va = kmap_atomic(from, KM_USER0);
+ mb();
+ ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
+ BUG_ON(ret != LZO_E_OK);
+ *out_va = dmem;
+ kunmap_atomic(from_va, KM_USER0);
+ ret = 1;
+out:
+ return ret;
+}
+
+
+static int zcache_cpu_notifier(struct notifier_block *nb,
+ unsigned long action, void *pcpu)
+{
+ int cpu = (long)pcpu;
+ struct zcache_preload *kp;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
+ GFP_KERNEL | __GFP_REPEAT,
+ LZO_DSTMEM_PAGE_ORDER),
+ per_cpu(zcache_workmem, cpu) =
+ kzalloc(LZO1X_MEM_COMPRESS,
+ GFP_KERNEL | __GFP_REPEAT);
+ break;
+ case CPU_DEAD:
+ case CPU_UP_CANCELED:
+ free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
+ LZO_DSTMEM_PAGE_ORDER);
+ per_cpu(zcache_dstmem, cpu) = NULL;
+ kfree(per_cpu(zcache_workmem, cpu));
+ per_cpu(zcache_workmem, cpu) = NULL;
+ kp = &per_cpu(zcache_preloads, cpu);
+ while (kp->nr) {
+ kmem_cache_free(zcache_objnode_cache,
+ kp->objnodes[kp->nr - 1]);
+ kp->objnodes[kp->nr - 1] = NULL;
+ kp->nr--;
+ }
+ kmem_cache_free(zcache_obj_cache, kp->obj);
+ free_page((unsigned long)kp->page);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block zcache_cpu_notifier_block = {
+ .notifier_call = zcache_cpu_notifier
+};
+
+#ifdef CONFIG_SYSFS
+#define ZCACHE_SYSFS_RO(_name) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return sprintf(buf, "%lu\n", zcache_##_name); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
+ static ssize_t zcache_##_name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+ { \
+ return _func(buf); \
+ } \
+ static struct kobj_attribute zcache_##_name##_attr = { \
+ .attr = { .name = __stringify(_name), .mode = 0444 }, \
+ .show = zcache_##_name##_show, \
+ }
+
+ZCACHE_SYSFS_RO(curr_obj_count_max);
+ZCACHE_SYSFS_RO(curr_objnode_count_max);
+ZCACHE_SYSFS_RO(flush_total);
+ZCACHE_SYSFS_RO(flush_found);
+ZCACHE_SYSFS_RO(flobj_total);
+ZCACHE_SYSFS_RO(flobj_found);
+ZCACHE_SYSFS_RO(failed_eph_puts);
+ZCACHE_SYSFS_RO(failed_pers_puts);
+ZCACHE_SYSFS_RO(zbud_curr_zbytes);
+ZCACHE_SYSFS_RO(zbud_cumul_zpages);
+ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
+ZCACHE_SYSFS_RO(zbud_buddied_count);
+ZCACHE_SYSFS_RO(zbpg_unused_list_count);
+ZCACHE_SYSFS_RO(evicted_raw_pages);
+ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
+ZCACHE_SYSFS_RO(evicted_buddied_pages);
+ZCACHE_SYSFS_RO(failed_get_free_pages);
+ZCACHE_SYSFS_RO(failed_alloc);
+ZCACHE_SYSFS_RO(put_to_flush);
+ZCACHE_SYSFS_RO(aborted_preload);
+ZCACHE_SYSFS_RO(aborted_shrink);
+ZCACHE_SYSFS_RO(compress_poor);
+ZCACHE_SYSFS_RO(mean_compress_poor);
+ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
+ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
+ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
+ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
+ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
+ zbud_show_unbuddied_list_counts);
+ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
+ zbud_show_cumul_chunk_counts);
+ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
+ zv_curr_dist_counts_show);
+ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
+ zv_cumul_dist_counts_show);
+
+static struct attribute *zcache_attrs[] = {
+ &zcache_curr_obj_count_attr.attr,
+ &zcache_curr_obj_count_max_attr.attr,
+ &zcache_curr_objnode_count_attr.attr,
+ &zcache_curr_objnode_count_max_attr.attr,
+ &zcache_flush_total_attr.attr,
+ &zcache_flobj_total_attr.attr,
+ &zcache_flush_found_attr.attr,
+ &zcache_flobj_found_attr.attr,
+ &zcache_failed_eph_puts_attr.attr,
+ &zcache_failed_pers_puts_attr.attr,
+ &zcache_compress_poor_attr.attr,
+ &zcache_mean_compress_poor_attr.attr,
+ &zcache_zbud_curr_raw_pages_attr.attr,
+ &zcache_zbud_curr_zpages_attr.attr,
+ &zcache_zbud_curr_zbytes_attr.attr,
+ &zcache_zbud_cumul_zpages_attr.attr,
+ &zcache_zbud_cumul_zbytes_attr.attr,
+ &zcache_zbud_buddied_count_attr.attr,
+ &zcache_zbpg_unused_list_count_attr.attr,
+ &zcache_evicted_raw_pages_attr.attr,
+ &zcache_evicted_unbuddied_pages_attr.attr,
+ &zcache_evicted_buddied_pages_attr.attr,
+ &zcache_failed_get_free_pages_attr.attr,
+ &zcache_failed_alloc_attr.attr,
+ &zcache_put_to_flush_attr.attr,
+ &zcache_aborted_preload_attr.attr,
+ &zcache_aborted_shrink_attr.attr,
+ &zcache_zbud_unbuddied_list_counts_attr.attr,
+ &zcache_zbud_cumul_chunk_counts_attr.attr,
+ &zcache_zv_curr_dist_counts_attr.attr,
+ &zcache_zv_cumul_dist_counts_attr.attr,
+ &zcache_zv_max_zsize_attr.attr,
+ &zcache_zv_max_mean_zsize_attr.attr,
+ &zcache_zv_page_count_policy_percent_attr.attr,
+ NULL,
+};
+
+static struct attribute_group zcache_attr_group = {
+ .attrs = zcache_attrs,
+ .name = "zcache",
+};
+
+#endif /* CONFIG_SYSFS */
+/*
+ * When zcache is disabled ("frozen"), pools can be created and destroyed,
+ * but all puts (and thus all other operations that require memory allocation)
+ * must fail. If zcache is unfrozen, accepts puts, then frozen again,
+ * data consistency requires all puts while frozen to be converted into
+ * flushes.
+ */
+static bool zcache_freeze;
+
+/*
+ * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
+ */
+static int shrink_zcache_memory(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ int ret = -1;
+ int nr = sc->nr_to_scan;
+ gfp_t gfp_mask = sc->gfp_mask;
+
+ if (nr >= 0) {
+ if (!(gfp_mask & __GFP_FS))
+ /* does this case really need to be skipped? */
+ goto out;
+ if (spin_trylock(&zcache_direct_reclaim_lock)) {
+ zbud_evict_pages(nr);
+ spin_unlock(&zcache_direct_reclaim_lock);
+ } else
+ zcache_aborted_shrink++;
+ }
+ ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
+out:
+ return ret;
+}
+
+static struct shrinker zcache_shrinker = {
+ .shrink = shrink_zcache_memory,
+ .seeks = DEFAULT_SEEKS,
+};
+
+/*
+ * zcache shims between cleancache/frontswap ops and tmem
+ */
+
+static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, struct page *page)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+
+ BUG_ON(!irqs_disabled());
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (unlikely(pool == NULL))
+ goto out;
+ if (!zcache_freeze && zcache_do_preload(pool) == 0) {
+ /* preload does preempt_disable on success */
+ ret = tmem_put(pool, oidp, index, page_address(page),
+ PAGE_SIZE, 0, is_ephemeral(pool));
+ if (ret < 0) {
+ if (is_ephemeral(pool))
+ zcache_failed_eph_puts++;
+ else
+ zcache_failed_pers_puts++;
+ }
+ zcache_put_pool(pool);
+ preempt_enable_no_resched();
+ } else {
+ zcache_put_to_flush++;
+ if (atomic_read(&pool->obj_count) > 0)
+ /* the put fails whether the flush succeeds or not */
+ (void)tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+out:
+ return ret;
+}
+
+static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
+ uint32_t index, struct page *page)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+ size_t size = PAGE_SIZE;
+
+ local_irq_save(flags);
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_get(pool, oidp, index, page_address(page),
+ &size, 0, is_ephemeral(pool));
+ zcache_put_pool(pool);
+ }
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_flush_page(int cli_id, int pool_id,
+ struct tmem_oid *oidp, uint32_t index)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flush_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_page(pool, oidp, index);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flush_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_flush_object(int cli_id, int pool_id,
+ struct tmem_oid *oidp)
+{
+ struct tmem_pool *pool;
+ int ret = -1;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ zcache_flobj_total++;
+ pool = zcache_get_pool_by_id(cli_id, pool_id);
+ if (likely(pool != NULL)) {
+ if (atomic_read(&pool->obj_count) > 0)
+ ret = tmem_flush_object(pool, oidp);
+ zcache_put_pool(pool);
+ }
+ if (ret >= 0)
+ zcache_flobj_found++;
+ local_irq_restore(flags);
+ return ret;
+}
+
+static int zcache_destroy_pool(int cli_id, int pool_id)
+{
+ struct tmem_pool *pool = NULL;
+ struct zcache_client *cli = NULL;
+ int ret = -1;
+
+ if (pool_id < 0)
+ goto out;
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = cli->tmem_pools[pool_id];
+ if (pool == NULL)
+ goto out;
+ cli->tmem_pools[pool_id] = NULL;
+ /* wait for pool activity on other cpus to quiesce */
+ while (atomic_read(&pool->refcount) != 0)
+ ;
+ atomic_dec(&cli->refcount);
+ local_bh_disable();
+ ret = tmem_destroy_pool(pool);
+ local_bh_enable();
+ kfree(pool);
+ pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
+ pool_id, cli_id);
+out:
+ return ret;
+}
+
+static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
+{
+ int poolid = -1;
+ struct tmem_pool *pool;
+ struct zcache_client *cli = NULL;
+
+ if (cli_id == LOCAL_CLIENT)
+ cli = &zcache_host;
+ else if ((unsigned int)cli_id < MAX_CLIENTS)
+ cli = &zcache_clients[cli_id];
+ if (cli == NULL)
+ goto out;
+ atomic_inc(&cli->refcount);
+ pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
+ if (pool == NULL) {
+ pr_info("zcache: pool creation failed: out of memory\n");
+ goto out;
+ }
+
+ for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
+ if (cli->tmem_pools[poolid] == NULL)
+ break;
+ if (poolid >= MAX_POOLS_PER_CLIENT) {
+ pr_info("zcache: pool creation failed: max exceeded\n");
+ kfree(pool);
+ poolid = -1;
+ goto out;
+ }
+ atomic_set(&pool->refcount, 0);
+ pool->client = cli;
+ pool->pool_id = poolid;
+ tmem_new_pool(pool, flags);
+ cli->tmem_pools[poolid] = pool;
+ pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
+ flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
+ poolid, cli_id);
+out:
+ if (cli != NULL)
+ atomic_dec(&cli->refcount);
+ return poolid;
+}
+
+/**********
+ * Two kernel functionalities currently can be layered on top of tmem.
+ * These are "cleancache" which is used as a second-chance cache for clean
+ * page cache pages; and "frontswap" which is used for swap pages
+ * to avoid writes to disk. A generic "shim" is provided here for each
+ * to translate in-kernel semantics to zcache semantics.
+ */
+
+#ifdef CONFIG_CLEANCACHE
+static void zcache_cleancache_put_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (likely(ind == index))
+ (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
+}
+
+static int zcache_cleancache_get_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index, struct page *page)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+ int ret = -1;
+
+ if (likely(ind == index))
+ ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
+ return ret;
+}
+
+static void zcache_cleancache_flush_page(int pool_id,
+ struct cleancache_filekey key,
+ pgoff_t index)
+{
+ u32 ind = (u32) index;
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ if (likely(ind == index))
+ (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
+}
+
+static void zcache_cleancache_flush_inode(int pool_id,
+ struct cleancache_filekey key)
+{
+ struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+ (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
+}
+
+static void zcache_cleancache_flush_fs(int pool_id)
+{
+ if (pool_id >= 0)
+ (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
+}
+
+static int zcache_cleancache_init_fs(size_t pagesize)
+{
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_new_pool(LOCAL_CLIENT, 0);
+}
+
+static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
+{
+ /* shared pools are unsupported and map to private */
+ BUG_ON(sizeof(struct cleancache_filekey) !=
+ sizeof(struct tmem_oid));
+ BUG_ON(pagesize != PAGE_SIZE);
+ return zcache_new_pool(LOCAL_CLIENT, 0);
+}
+
+static struct cleancache_ops zcache_cleancache_ops = {
+ .put_page = zcache_cleancache_put_page,
+ .get_page = zcache_cleancache_get_page,
+ .flush_page = zcache_cleancache_flush_page,
+ .flush_inode = zcache_cleancache_flush_inode,
+ .flush_fs = zcache_cleancache_flush_fs,
+ .init_shared_fs = zcache_cleancache_init_shared_fs,
+ .init_fs = zcache_cleancache_init_fs
+};
+
+struct cleancache_ops zcache_cleancache_register_ops(void)
+{
+ struct cleancache_ops old_ops =
+ cleancache_register_ops(&zcache_cleancache_ops);
+
+ return old_ops;
+}
+#endif
+
+#ifdef CONFIG_FRONTSWAP
+/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+static int zcache_frontswap_poolid = -1;
+
+/*
+ * Swizzling increases objects per swaptype, increasing tmem concurrency
+ * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
+ */
+#define SWIZ_BITS 4
+#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
+#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
+#define iswiz(_ind) (_ind >> SWIZ_BITS)
+
+static inline struct tmem_oid oswiz(unsigned type, u32 ind)
+{
+ struct tmem_oid oid = { .oid = { 0 } };
+ oid.oid[0] = _oswiz(type, ind);
+ return oid;
+}
+
+static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ int ret = -1;
+ unsigned long flags;
+
+ BUG_ON(!PageLocked(page));
+ if (likely(ind64 == ind)) {
+ local_irq_save(flags);
+ ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind), page);
+ local_irq_restore(flags);
+ }
+ return ret;
+}
+
+/* returns 0 if the page was successfully gotten from frontswap, -1 if
+ * was not present (should never happen!) */
+static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+ int ret = -1;
+
+ BUG_ON(!PageLocked(page));
+ if (likely(ind64 == ind))
+ ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind), page);
+ return ret;
+}
+
+/* flush a single page from frontswap */
+static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ struct tmem_oid oid = oswiz(type, ind);
+
+ if (likely(ind64 == ind))
+ (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
+ &oid, iswiz(ind));
+}
+
+/* flush all pages from the passed swaptype */
+static void zcache_frontswap_flush_area(unsigned type)
+{
+ struct tmem_oid oid;
+ int ind;
+
+ for (ind = SWIZ_MASK; ind >= 0; ind--) {
+ oid = oswiz(type, ind);
+ (void)zcache_flush_object(LOCAL_CLIENT,
+ zcache_frontswap_poolid, &oid);
+ }
+}
+
+static void zcache_frontswap_init(unsigned ignored)
+{
+ /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+ if (zcache_frontswap_poolid < 0)
+ zcache_frontswap_poolid =
+ zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
+}
+
+static struct frontswap_ops zcache_frontswap_ops = {
+ .put_page = zcache_frontswap_put_page,
+ .get_page = zcache_frontswap_get_page,
+ .flush_page = zcache_frontswap_flush_page,
+ .flush_area = zcache_frontswap_flush_area,
+ .init = zcache_frontswap_init
+};
+
+struct frontswap_ops zcache_frontswap_register_ops(void)
+{
+ struct frontswap_ops old_ops =
+ frontswap_register_ops(&zcache_frontswap_ops);
+
+ return old_ops;
+}
+#endif
+
+/*
+ * zcache initialization
+ * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
+ * NOTHING HAPPENS!
+ */
+
+static int zcache_enabled;
+
+static int __init enable_zcache(char *s)
+{
+ zcache_enabled = 1;
+ return 1;
+}
+__setup("zcache", enable_zcache);
+
+/* allow independent dynamic disabling of cleancache and frontswap */
+
+static int use_cleancache = 1;
+
+static int __init no_cleancache(char *s)
+{
+ use_cleancache = 0;
+ return 1;
+}
+
+__setup("nocleancache", no_cleancache);
+
+static int use_frontswap = 1;
+
+static int __init no_frontswap(char *s)
+{
+ use_frontswap = 0;
+ return 1;
+}
+
+__setup("nofrontswap", no_frontswap);
+
+static int __init zcache_init(void)
+{
+#ifdef CONFIG_SYSFS
+ int ret = 0;
+
+ ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
+ if (ret) {
+ pr_err("zcache: can't create sysfs\n");
+ goto out;
+ }
+#endif /* CONFIG_SYSFS */
+#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
+ if (zcache_enabled) {
+ unsigned int cpu;
+
+ tmem_register_hostops(&zcache_hostops);
+ tmem_register_pamops(&zcache_pamops);
+ ret = register_cpu_notifier(&zcache_cpu_notifier_block);
+ if (ret) {
+ pr_err("zcache: can't register cpu notifier\n");
+ goto out;
+ }
+ for_each_online_cpu(cpu) {
+ void *pcpu = (void *)(long)cpu;
+ zcache_cpu_notifier(&zcache_cpu_notifier_block,
+ CPU_UP_PREPARE, pcpu);
+ }
+ }
+ zcache_objnode_cache = kmem_cache_create("zcache_objnode",
+ sizeof(struct tmem_objnode), 0, 0, NULL);
+ zcache_obj_cache = kmem_cache_create("zcache_obj",
+ sizeof(struct tmem_obj), 0, 0, NULL);
+ ret = zcache_new_client(LOCAL_CLIENT);
+ if (ret) {
+ pr_err("zcache: can't create client\n");
+ goto out;
+ }
+#endif
+#ifdef CONFIG_CLEANCACHE
+ if (zcache_enabled && use_cleancache) {
+ struct cleancache_ops old_ops;
+
+ zbud_init();
+ register_shrinker(&zcache_shrinker);
+ old_ops = zcache_cleancache_register_ops();
+ pr_info("zcache: cleancache enabled using kernel "
+ "transcendent memory and compression buddies\n");
+ if (old_ops.init_fs != NULL)
+ pr_warning("zcache: cleancache_ops overridden");
+ }
+#endif
+#ifdef CONFIG_FRONTSWAP
+ if (zcache_enabled && use_frontswap) {
+ struct frontswap_ops old_ops;
+
+ old_ops = zcache_frontswap_register_ops();
+ pr_info("zcache: frontswap enabled using kernel "
+ "transcendent memory and xvmalloc\n");
+ if (old_ops.init != NULL)
+ pr_warning("ktmem: frontswap_ops overridden");
+ }
+#endif
+out:
+ return ret;
+}
+
+module_init(zcache_init)
diff --git a/drivers/staging/zcache/zcache.c b/drivers/staging/zcache/zcache.c
deleted file mode 100644
index 65a81a0..0000000
--- a/drivers/staging/zcache/zcache.c
+++ /dev/null
@@ -1,1996 +0,0 @@
-/*
- * zcache.c
- *
- * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
- * Copyright (c) 2010,2011, Nitin Gupta
- *
- * Zcache provides an in-kernel "host implementation" for transcendent memory
- * and, thus indirectly, for cleancache and frontswap. Zcache includes two
- * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
- * 1) "compression buddies" ("zbud") is used for ephemeral pages
- * 2) xvmalloc is used for persistent pages.
- * Xvmalloc (based on the TLSF allocator) has very low fragmentation
- * so maximizes space efficiency, while zbud allows pairs (and potentially,
- * in the future, more than a pair of) compressed pages to be closely linked
- * so that reclaiming can be done via the kernel's physical-page-oriented
- * "shrinker" interface.
- *
- * [1] For a definition of page-accessible memory (aka PAM), see:
- * http://marc.info/?l=linux-mm&m=127811271605009
- */
-
-#include <linux/cpu.h>
-#include <linux/highmem.h>
-#include <linux/list.h>
-#include <linux/lzo.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/types.h>
-#include <linux/atomic.h>
-#include "tmem.h"
-
-#include "../zram/xvmalloc.h" /* if built in drivers/staging */
-
-#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
-#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
-#endif
-#ifdef CONFIG_CLEANCACHE
-#include <linux/cleancache.h>
-#endif
-#ifdef CONFIG_FRONTSWAP
-#include <linux/frontswap.h>
-#endif
-
-#if 0
-/* this is more aggressive but may cause other problems? */
-#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
-#else
-#define ZCACHE_GFP_MASK \
- (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
-#endif
-
-#define MAX_POOLS_PER_CLIENT 16
-
-#define MAX_CLIENTS 16
-#define LOCAL_CLIENT ((uint16_t)-1)
-struct zcache_client {
- struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
- struct xv_pool *xvpool;
- bool allocated;
- atomic_t refcount;
-};
-
-static struct zcache_client zcache_host;
-static struct zcache_client zcache_clients[MAX_CLIENTS];
-
-static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
-{
- BUG_ON(cli == NULL);
- if (cli == &zcache_host)
- return LOCAL_CLIENT;
- return cli - &zcache_clients[0];
-}
-
-static inline bool is_local_client(struct zcache_client *cli)
-{
- return cli == &zcache_host;
-}
-
-/**********
- * Compression buddies ("zbud") provides for packing two (or, possibly
- * in the future, more) compressed ephemeral pages into a single "raw"
- * (physical) page and tracking them with data structures so that
- * the raw pages can be easily reclaimed.
- *
- * A zbud page ("zbpg") is an aligned page containing a list_head,
- * a lock, and two "zbud headers". The remainder of the physical
- * page is divided up into aligned 64-byte "chunks" which contain
- * the compressed data for zero, one, or two zbuds. Each zbpg
- * resides on: (1) an "unused list" if it has no zbuds; (2) a
- * "buddied" list if it is fully populated with two zbuds; or
- * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
- * the one unbuddied zbud uses. The data inside a zbpg cannot be
- * read or written unless the zbpg's lock is held.
- */
-
-#define ZBH_SENTINEL 0x43214321
-#define ZBPG_SENTINEL 0xdeadbeef
-
-#define ZBUD_MAX_BUDS 2
-
-struct zbud_hdr {
- uint16_t client_id;
- uint16_t pool_id;
- struct tmem_oid oid;
- uint32_t index;
- uint16_t size; /* compressed size in bytes, zero means unused */
- DECL_SENTINEL
-};
-
-struct zbud_page {
- struct list_head bud_list;
- spinlock_t lock;
- struct zbud_hdr buddy[ZBUD_MAX_BUDS];
- DECL_SENTINEL
- /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
-};
-
-#define CHUNK_SHIFT 6
-#define CHUNK_SIZE (1 << CHUNK_SHIFT)
-#define CHUNK_MASK (~(CHUNK_SIZE-1))
-#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
- CHUNK_MASK) >> CHUNK_SHIFT)
-#define MAX_CHUNK (NCHUNKS-1)
-
-static struct {
- struct list_head list;
- unsigned count;
-} zbud_unbuddied[NCHUNKS];
-/* list N contains pages with N chunks USED and NCHUNKS-N unused */
-/* element 0 is never used but optimizing that isn't worth it */
-static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
-
-struct list_head zbud_buddied_list;
-static unsigned long zcache_zbud_buddied_count;
-
-/* protects the buddied list and all unbuddied lists */
-static DEFINE_SPINLOCK(zbud_budlists_spinlock);
-
-static LIST_HEAD(zbpg_unused_list);
-static unsigned long zcache_zbpg_unused_list_count;
-
-/* protects the unused page list */
-static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
-
-static atomic_t zcache_zbud_curr_raw_pages;
-static atomic_t zcache_zbud_curr_zpages;
-static unsigned long zcache_zbud_curr_zbytes;
-static unsigned long zcache_zbud_cumul_zpages;
-static unsigned long zcache_zbud_cumul_zbytes;
-static unsigned long zcache_compress_poor;
-static unsigned long zcache_mean_compress_poor;
-
-/* forward references */
-static void *zcache_get_free_page(void);
-static void zcache_free_page(void *p);
-
-/*
- * zbud helper functions
- */
-
-static inline unsigned zbud_max_buddy_size(void)
-{
- return MAX_CHUNK << CHUNK_SHIFT;
-}
-
-static inline unsigned zbud_size_to_chunks(unsigned size)
-{
- BUG_ON(size == 0 || size > zbud_max_buddy_size());
- return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
-}
-
-static inline int zbud_budnum(struct zbud_hdr *zh)
-{
- unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
- struct zbud_page *zbpg = NULL;
- unsigned budnum = -1U;
- int i;
-
- for (i = 0; i < ZBUD_MAX_BUDS; i++)
- if (offset == offsetof(typeof(*zbpg), buddy[i])) {
- budnum = i;
- break;
- }
- BUG_ON(budnum == -1U);
- return budnum;
-}
-
-static char *zbud_data(struct zbud_hdr *zh, unsigned size)
-{
- struct zbud_page *zbpg;
- char *p;
- unsigned budnum;
-
- ASSERT_SENTINEL(zh, ZBH);
- budnum = zbud_budnum(zh);
- BUG_ON(size == 0 || size > zbud_max_buddy_size());
- zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
- ASSERT_SPINLOCK(&zbpg->lock);
- p = (char *)zbpg;
- if (budnum == 0)
- p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
- CHUNK_MASK);
- else if (budnum == 1)
- p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
- return p;
-}
-
-/*
- * zbud raw page management
- */
-
-static struct zbud_page *zbud_alloc_raw_page(void)
-{
- struct zbud_page *zbpg = NULL;
- struct zbud_hdr *zh0, *zh1;
- bool recycled = 0;
-
- /* if any pages on the zbpg list, use one */
- spin_lock(&zbpg_unused_list_spinlock);
- if (!list_empty(&zbpg_unused_list)) {
- zbpg = list_first_entry(&zbpg_unused_list,
- struct zbud_page, bud_list);
- list_del_init(&zbpg->bud_list);
- zcache_zbpg_unused_list_count--;
- recycled = 1;
- }
- spin_unlock(&zbpg_unused_list_spinlock);
- if (zbpg == NULL)
- /* none on zbpg list, try to get a kernel page */
- zbpg = zcache_get_free_page();
- if (likely(zbpg != NULL)) {
- INIT_LIST_HEAD(&zbpg->bud_list);
- zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
- spin_lock_init(&zbpg->lock);
- if (recycled) {
- ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
- SET_SENTINEL(zbpg, ZBPG);
- BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
- BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
- } else {
- atomic_inc(&zcache_zbud_curr_raw_pages);
- INIT_LIST_HEAD(&zbpg->bud_list);
- SET_SENTINEL(zbpg, ZBPG);
- zh0->size = 0; zh1->size = 0;
- tmem_oid_set_invalid(&zh0->oid);
- tmem_oid_set_invalid(&zh1->oid);
- }
- }
- return zbpg;
-}
-
-static void zbud_free_raw_page(struct zbud_page *zbpg)
-{
- struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
-
- ASSERT_SENTINEL(zbpg, ZBPG);
- BUG_ON(!list_empty(&zbpg->bud_list));
- ASSERT_SPINLOCK(&zbpg->lock);
- BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
- BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
- INVERT_SENTINEL(zbpg, ZBPG);
- spin_unlock(&zbpg->lock);
- spin_lock(&zbpg_unused_list_spinlock);
- list_add(&zbpg->bud_list, &zbpg_unused_list);
- zcache_zbpg_unused_list_count++;
- spin_unlock(&zbpg_unused_list_spinlock);
-}
-
-/*
- * core zbud handling routines
- */
-
-static unsigned zbud_free(struct zbud_hdr *zh)
-{
- unsigned size;
-
- ASSERT_SENTINEL(zh, ZBH);
- BUG_ON(!tmem_oid_valid(&zh->oid));
- size = zh->size;
- BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
- zh->size = 0;
- tmem_oid_set_invalid(&zh->oid);
- INVERT_SENTINEL(zh, ZBH);
- zcache_zbud_curr_zbytes -= size;
- atomic_dec(&zcache_zbud_curr_zpages);
- return size;
-}
-
-static void zbud_free_and_delist(struct zbud_hdr *zh)
-{
- unsigned chunks;
- struct zbud_hdr *zh_other;
- unsigned budnum = zbud_budnum(zh), size;
- struct zbud_page *zbpg =
- container_of(zh, struct zbud_page, buddy[budnum]);
-
- spin_lock(&zbpg->lock);
- if (list_empty(&zbpg->bud_list)) {
- /* ignore zombie page... see zbud_evict_pages() */
- spin_unlock(&zbpg->lock);
- return;
- }
- size = zbud_free(zh);
- ASSERT_SPINLOCK(&zbpg->lock);
- zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
- if (zh_other->size == 0) { /* was unbuddied: unlist and free */
- chunks = zbud_size_to_chunks(size) ;
- spin_lock(&zbud_budlists_spinlock);
- BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[chunks].count--;
- spin_unlock(&zbud_budlists_spinlock);
- zbud_free_raw_page(zbpg);
- } else { /* was buddied: move remaining buddy to unbuddied list */
- chunks = zbud_size_to_chunks(zh_other->size) ;
- spin_lock(&zbud_budlists_spinlock);
- list_del_init(&zbpg->bud_list);
- zcache_zbud_buddied_count--;
- list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
- zbud_unbuddied[chunks].count++;
- spin_unlock(&zbud_budlists_spinlock);
- spin_unlock(&zbpg->lock);
- }
-}
-
-static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
- struct tmem_oid *oid,
- uint32_t index, struct page *page,
- void *cdata, unsigned size)
-{
- struct zbud_hdr *zh0, *zh1, *zh = NULL;
- struct zbud_page *zbpg = NULL, *ztmp;
- unsigned nchunks;
- char *to;
- int i, found_good_buddy = 0;
-
- nchunks = zbud_size_to_chunks(size) ;
- for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
- spin_lock(&zbud_budlists_spinlock);
- if (!list_empty(&zbud_unbuddied[i].list)) {
- list_for_each_entry_safe(zbpg, ztmp,
- &zbud_unbuddied[i].list, bud_list) {
- if (spin_trylock(&zbpg->lock)) {
- found_good_buddy = i;
- goto found_unbuddied;
- }
- }
- }
- spin_unlock(&zbud_budlists_spinlock);
- }
- /* didn't find a good buddy, try allocating a new page */
- zbpg = zbud_alloc_raw_page();
- if (unlikely(zbpg == NULL))
- goto out;
- /* ok, have a page, now compress the data before taking locks */
- spin_lock(&zbpg->lock);
- spin_lock(&zbud_budlists_spinlock);
- list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
- zbud_unbuddied[nchunks].count++;
- zh = &zbpg->buddy[0];
- goto init_zh;
-
-found_unbuddied:
- ASSERT_SPINLOCK(&zbpg->lock);
- zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
- BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
- if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
- ASSERT_SENTINEL(zh0, ZBH);
- zh = zh1;
- } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
- ASSERT_SENTINEL(zh1, ZBH);
- zh = zh0;
- } else
- BUG();
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[found_good_buddy].count--;
- list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
- zcache_zbud_buddied_count++;
-
-init_zh:
- SET_SENTINEL(zh, ZBH);
- zh->size = size;
- zh->index = index;
- zh->oid = *oid;
- zh->pool_id = pool_id;
- zh->client_id = client_id;
- /* can wait to copy the data until the list locks are dropped */
- spin_unlock(&zbud_budlists_spinlock);
-
- to = zbud_data(zh, size);
- memcpy(to, cdata, size);
- spin_unlock(&zbpg->lock);
- zbud_cumul_chunk_counts[nchunks]++;
- atomic_inc(&zcache_zbud_curr_zpages);
- zcache_zbud_cumul_zpages++;
- zcache_zbud_curr_zbytes += size;
- zcache_zbud_cumul_zbytes += size;
-out:
- return zh;
-}
-
-static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
-{
- struct zbud_page *zbpg;
- unsigned budnum = zbud_budnum(zh);
- size_t out_len = PAGE_SIZE;
- char *to_va, *from_va;
- unsigned size;
- int ret = 0;
-
- zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
- spin_lock(&zbpg->lock);
- if (list_empty(&zbpg->bud_list)) {
- /* ignore zombie page... see zbud_evict_pages() */
- ret = -EINVAL;
- goto out;
- }
- ASSERT_SENTINEL(zh, ZBH);
- BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
- to_va = kmap_atomic(page, KM_USER0);
- size = zh->size;
- from_va = zbud_data(zh, size);
- ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
- BUG_ON(ret != LZO_E_OK);
- BUG_ON(out_len != PAGE_SIZE);
- kunmap_atomic(to_va, KM_USER0);
-out:
- spin_unlock(&zbpg->lock);
- return ret;
-}
-
-/*
- * The following routines handle shrinking of ephemeral pages by evicting
- * pages "least valuable" first.
- */
-
-static unsigned long zcache_evicted_raw_pages;
-static unsigned long zcache_evicted_buddied_pages;
-static unsigned long zcache_evicted_unbuddied_pages;
-
-static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
- uint16_t poolid);
-static void zcache_put_pool(struct tmem_pool *pool);
-
-/*
- * Flush and free all zbuds in a zbpg, then free the pageframe
- */
-static void zbud_evict_zbpg(struct zbud_page *zbpg)
-{
- struct zbud_hdr *zh;
- int i, j;
- uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
- uint32_t index[ZBUD_MAX_BUDS];
- struct tmem_oid oid[ZBUD_MAX_BUDS];
- struct tmem_pool *pool;
-
- ASSERT_SPINLOCK(&zbpg->lock);
- BUG_ON(!list_empty(&zbpg->bud_list));
- for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
- zh = &zbpg->buddy[i];
- if (zh->size) {
- client_id[j] = zh->client_id;
- pool_id[j] = zh->pool_id;
- oid[j] = zh->oid;
- index[j] = zh->index;
- j++;
- zbud_free(zh);
- }
- }
- spin_unlock(&zbpg->lock);
- for (i = 0; i < j; i++) {
- pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
- if (pool != NULL) {
- tmem_flush_page(pool, &oid[i], index[i]);
- zcache_put_pool(pool);
- }
- }
- ASSERT_SENTINEL(zbpg, ZBPG);
- spin_lock(&zbpg->lock);
- zbud_free_raw_page(zbpg);
-}
-
-/*
- * Free nr pages. This code is funky because we want to hold the locks
- * protecting various lists for as short a time as possible, and in some
- * circumstances the list may change asynchronously when the list lock is
- * not held. In some cases we also trylock not only to avoid waiting on a
- * page in use by another cpu, but also to avoid potential deadlock due to
- * lock inversion.
- */
-static void zbud_evict_pages(int nr)
-{
- struct zbud_page *zbpg;
- int i;
-
- /* first try freeing any pages on unused list */
-retry_unused_list:
- spin_lock_bh(&zbpg_unused_list_spinlock);
- if (!list_empty(&zbpg_unused_list)) {
- /* can't walk list here, since it may change when unlocked */
- zbpg = list_first_entry(&zbpg_unused_list,
- struct zbud_page, bud_list);
- list_del_init(&zbpg->bud_list);
- zcache_zbpg_unused_list_count--;
- atomic_dec(&zcache_zbud_curr_raw_pages);
- spin_unlock_bh(&zbpg_unused_list_spinlock);
- zcache_free_page(zbpg);
- zcache_evicted_raw_pages++;
- if (--nr <= 0)
- goto out;
- goto retry_unused_list;
- }
- spin_unlock_bh(&zbpg_unused_list_spinlock);
-
- /* now try freeing unbuddied pages, starting with least space avail */
- for (i = 0; i < MAX_CHUNK; i++) {
-retry_unbud_list_i:
- spin_lock_bh(&zbud_budlists_spinlock);
- if (list_empty(&zbud_unbuddied[i].list)) {
- spin_unlock_bh(&zbud_budlists_spinlock);
- continue;
- }
- list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
- if (unlikely(!spin_trylock(&zbpg->lock)))
- continue;
- list_del_init(&zbpg->bud_list);
- zbud_unbuddied[i].count--;
- spin_unlock(&zbud_budlists_spinlock);
- zcache_evicted_unbuddied_pages++;
- /* want budlists unlocked when doing zbpg eviction */
- zbud_evict_zbpg(zbpg);
- local_bh_enable();
- if (--nr <= 0)
- goto out;
- goto retry_unbud_list_i;
- }
- spin_unlock_bh(&zbud_budlists_spinlock);
- }
-
- /* as a last resort, free buddied pages */
-retry_bud_list:
- spin_lock_bh(&zbud_budlists_spinlock);
- if (list_empty(&zbud_buddied_list)) {
- spin_unlock_bh(&zbud_budlists_spinlock);
- goto out;
- }
- list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
- if (unlikely(!spin_trylock(&zbpg->lock)))
- continue;
- list_del_init(&zbpg->bud_list);
- zcache_zbud_buddied_count--;
- spin_unlock(&zbud_budlists_spinlock);
- zcache_evicted_buddied_pages++;
- /* want budlists unlocked when doing zbpg eviction */
- zbud_evict_zbpg(zbpg);
- local_bh_enable();
- if (--nr <= 0)
- goto out;
- goto retry_bud_list;
- }
- spin_unlock_bh(&zbud_budlists_spinlock);
-out:
- return;
-}
-
-static void zbud_init(void)
-{
- int i;
-
- INIT_LIST_HEAD(&zbud_buddied_list);
- zcache_zbud_buddied_count = 0;
- for (i = 0; i < NCHUNKS; i++) {
- INIT_LIST_HEAD(&zbud_unbuddied[i].list);
- zbud_unbuddied[i].count = 0;
- }
-}
-
-#ifdef CONFIG_SYSFS
-/*
- * These sysfs routines show a nice distribution of how many zbpg's are
- * currently (and have ever been placed) in each unbuddied list. It's fun
- * to watch but can probably go away before final merge.
- */
-static int zbud_show_unbuddied_list_counts(char *buf)
-{
- int i;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++)
- p += sprintf(p, "%u ", zbud_unbuddied[i].count);
- return p - buf;
-}
-
-static int zbud_show_cumul_chunk_counts(char *buf)
-{
- unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
- unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
- unsigned long total_chunks_lte_42 = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
- chunks += zbud_cumul_chunk_counts[i];
- total_chunks += zbud_cumul_chunk_counts[i];
- sum_total_chunks += i * zbud_cumul_chunk_counts[i];
- if (i == 21)
- total_chunks_lte_21 = total_chunks;
- if (i == 32)
- total_chunks_lte_32 = total_chunks;
- if (i == 42)
- total_chunks_lte_42 = total_chunks;
- }
- p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
- total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-#endif
-
-/**********
- * This "zv" PAM implementation combines the TLSF-based xvMalloc
- * with lzo1x compression to maximize the amount of data that can
- * be packed into a physical page.
- *
- * Zv represents a PAM page with the index and object (plus a "size" value
- * necessary for decompression) immediately preceding the compressed data.
- */
-
-#define ZVH_SENTINEL 0x43214321
-
-struct zv_hdr {
- uint32_t pool_id;
- struct tmem_oid oid;
- uint32_t index;
- DECL_SENTINEL
-};
-
-/* rudimentary policy limits */
-/* total number of persistent pages may not exceed this percentage */
-static unsigned int zv_page_count_policy_percent = 75;
-/*
- * byte count defining poor compression; pages with greater zsize will be
- * rejected
- */
-static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
-/*
- * byte count defining poor *mean* compression; pages with greater zsize
- * will be rejected until sufficient better-compressed pages are accepted
- * driving the man below this threshold
- */
-static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
-
-static unsigned long zv_curr_dist_counts[NCHUNKS];
-static unsigned long zv_cumul_dist_counts[NCHUNKS];
-
-static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
- struct tmem_oid *oid, uint32_t index,
- void *cdata, unsigned clen)
-{
- struct page *page;
- struct zv_hdr *zv = NULL;
- uint32_t offset;
- int alloc_size = clen + sizeof(struct zv_hdr);
- int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
- int ret;
-
- BUG_ON(!irqs_disabled());
- BUG_ON(chunks >= NCHUNKS);
- ret = xv_malloc(xvpool, alloc_size,
- &page, &offset, ZCACHE_GFP_MASK);
- if (unlikely(ret))
- goto out;
- zv_curr_dist_counts[chunks]++;
- zv_cumul_dist_counts[chunks]++;
- zv = kmap_atomic(page, KM_USER0) + offset;
- zv->index = index;
- zv->oid = *oid;
- zv->pool_id = pool_id;
- SET_SENTINEL(zv, ZVH);
- memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
- kunmap_atomic(zv, KM_USER0);
-out:
- return zv;
-}
-
-static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
-{
- unsigned long flags;
- struct page *page;
- uint32_t offset;
- uint16_t size = xv_get_object_size(zv);
- int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
-
- ASSERT_SENTINEL(zv, ZVH);
- BUG_ON(chunks >= NCHUNKS);
- zv_curr_dist_counts[chunks]--;
- size -= sizeof(*zv);
- BUG_ON(size == 0);
- INVERT_SENTINEL(zv, ZVH);
- page = virt_to_page(zv);
- offset = (unsigned long)zv & ~PAGE_MASK;
- local_irq_save(flags);
- xv_free(xvpool, page, offset);
- local_irq_restore(flags);
-}
-
-static void zv_decompress(struct page *page, struct zv_hdr *zv)
-{
- size_t clen = PAGE_SIZE;
- char *to_va;
- unsigned size;
- int ret;
-
- ASSERT_SENTINEL(zv, ZVH);
- size = xv_get_object_size(zv) - sizeof(*zv);
- BUG_ON(size == 0);
- to_va = kmap_atomic(page, KM_USER0);
- ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
- size, to_va, &clen);
- kunmap_atomic(to_va, KM_USER0);
- BUG_ON(ret != LZO_E_OK);
- BUG_ON(clen != PAGE_SIZE);
-}
-
-#ifdef CONFIG_SYSFS
-/*
- * show a distribution of compression stats for zv pages.
- */
-
-static int zv_curr_dist_counts_show(char *buf)
-{
- unsigned long i, n, chunks = 0, sum_total_chunks = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- n = zv_curr_dist_counts[i];
- p += sprintf(p, "%lu ", n);
- chunks += n;
- sum_total_chunks += i * n;
- }
- p += sprintf(p, "mean:%lu\n",
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-
-static int zv_cumul_dist_counts_show(char *buf)
-{
- unsigned long i, n, chunks = 0, sum_total_chunks = 0;
- char *p = buf;
-
- for (i = 0; i < NCHUNKS; i++) {
- n = zv_cumul_dist_counts[i];
- p += sprintf(p, "%lu ", n);
- chunks += n;
- sum_total_chunks += i * n;
- }
- p += sprintf(p, "mean:%lu\n",
- chunks == 0 ? 0 : sum_total_chunks / chunks);
- return p - buf;
-}
-
-/*
- * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
- * pages that don't compress to less than this value (including metadata
- * overhead) to be rejected. We don't allow the value to get too close
- * to PAGE_SIZE.
- */
-static ssize_t zv_max_zsize_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_max_zsize);
-}
-
-static ssize_t zv_max_zsize_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
- return -EINVAL;
- zv_max_zsize = val;
- return count;
-}
-
-/*
- * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
- * pages that don't compress to less than this value (including metadata
- * overhead) to be rejected UNLESS the mean compression is also smaller
- * than this value. In other words, we are load-balancing-by-zsize the
- * accepted pages. Again, we don't allow the value to get too close
- * to PAGE_SIZE.
- */
-static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_max_mean_zsize);
-}
-
-static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
- return -EINVAL;
- zv_max_mean_zsize = val;
- return count;
-}
-
-/*
- * setting zv_page_count_policy_percent via sysfs sets an upper bound of
- * persistent (e.g. swap) pages that will be retained according to:
- * (zv_page_count_policy_percent * totalram_pages) / 100)
- * when that limit is reached, further puts will be rejected (until
- * some pages have been flushed). Note that, due to compression,
- * this number may exceed 100; it defaults to 75 and we set an
- * arbitary limit of 150. A poor choice will almost certainly result
- * in OOM's, so this value should only be changed prudently.
- */
-static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
- struct kobj_attribute *attr,
- char *buf)
-{
- return sprintf(buf, "%u\n", zv_page_count_policy_percent);
-}
-
-static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = strict_strtoul(buf, 10, &val);
- if (err || (val == 0) || (val > 150))
- return -EINVAL;
- zv_page_count_policy_percent = val;
- return count;
-}
-
-static struct kobj_attribute zcache_zv_max_zsize_attr = {
- .attr = { .name = "zv_max_zsize", .mode = 0644 },
- .show = zv_max_zsize_show,
- .store = zv_max_zsize_store,
-};
-
-static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
- .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
- .show = zv_max_mean_zsize_show,
- .store = zv_max_mean_zsize_store,
-};
-
-static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
- .attr = { .name = "zv_page_count_policy_percent",
- .mode = 0644 },
- .show = zv_page_count_policy_percent_show,
- .store = zv_page_count_policy_percent_store,
-};
-#endif
-
-/*
- * zcache core code starts here
- */
-
-/* useful stats not collected by cleancache or frontswap */
-static unsigned long zcache_flush_total;
-static unsigned long zcache_flush_found;
-static unsigned long zcache_flobj_total;
-static unsigned long zcache_flobj_found;
-static unsigned long zcache_failed_eph_puts;
-static unsigned long zcache_failed_pers_puts;
-
-/*
- * Tmem operations assume the poolid implies the invoking client.
- * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
- * RAMster has each client numbered by cluster node, and a KVM version
- * of zcache would have one client per guest and each client might
- * have a poolid==N.
- */
-static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
-{
- struct tmem_pool *pool = NULL;
- struct zcache_client *cli = NULL;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else {
- if (cli_id >= MAX_CLIENTS)
- goto out;
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- }
- if (poolid < MAX_POOLS_PER_CLIENT) {
- pool = cli->tmem_pools[poolid];
- if (pool != NULL)
- atomic_inc(&pool->refcount);
- }
-out:
- return pool;
-}
-
-static void zcache_put_pool(struct tmem_pool *pool)
-{
- struct zcache_client *cli = NULL;
-
- if (pool == NULL)
- BUG();
- cli = pool->client;
- atomic_dec(&pool->refcount);
- atomic_dec(&cli->refcount);
-}
-
-int zcache_new_client(uint16_t cli_id)
-{
- struct zcache_client *cli = NULL;
- int ret = -1;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- if (cli->allocated)
- goto out;
- cli->allocated = 1;
-#ifdef CONFIG_FRONTSWAP
- cli->xvpool = xv_create_pool();
- if (cli->xvpool == NULL)
- goto out;
-#endif
- ret = 0;
-out:
- return ret;
-}
-
-/* counters for debugging */
-static unsigned long zcache_failed_get_free_pages;
-static unsigned long zcache_failed_alloc;
-static unsigned long zcache_put_to_flush;
-static unsigned long zcache_aborted_preload;
-static unsigned long zcache_aborted_shrink;
-
-/*
- * Ensure that memory allocation requests in zcache don't result
- * in direct reclaim requests via the shrinker, which would cause
- * an infinite loop. Maybe a GFP flag would be better?
- */
-static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
-
-/*
- * for now, used named slabs so can easily track usage; later can
- * either just use kmalloc, or perhaps add a slab-like allocator
- * to more carefully manage total memory utilization
- */
-static struct kmem_cache *zcache_objnode_cache;
-static struct kmem_cache *zcache_obj_cache;
-static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_obj_count_max;
-static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_objnode_count_max;
-
-/*
- * to avoid memory allocation recursion (e.g. due to direct reclaim), we
- * preload all necessary data structures so the hostops callbacks never
- * actually do a malloc
- */
-struct zcache_preload {
- void *page;
- struct tmem_obj *obj;
- int nr;
- struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
-};
-static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
-
-static int zcache_do_preload(struct tmem_pool *pool)
-{
- struct zcache_preload *kp;
- struct tmem_objnode *objnode;
- struct tmem_obj *obj;
- void *page;
- int ret = -ENOMEM;
-
- if (unlikely(zcache_objnode_cache == NULL))
- goto out;
- if (unlikely(zcache_obj_cache == NULL))
- goto out;
- if (!spin_trylock(&zcache_direct_reclaim_lock)) {
- zcache_aborted_preload++;
- goto out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
- preempt_enable_no_resched();
- objnode = kmem_cache_alloc(zcache_objnode_cache,
- ZCACHE_GFP_MASK);
- if (unlikely(objnode == NULL)) {
- zcache_failed_alloc++;
- goto unlock_out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->nr < ARRAY_SIZE(kp->objnodes))
- kp->objnodes[kp->nr++] = objnode;
- else
- kmem_cache_free(zcache_objnode_cache, objnode);
- }
- preempt_enable_no_resched();
- obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
- if (unlikely(obj == NULL)) {
- zcache_failed_alloc++;
- goto unlock_out;
- }
- page = (void *)__get_free_page(ZCACHE_GFP_MASK);
- if (unlikely(page == NULL)) {
- zcache_failed_get_free_pages++;
- kmem_cache_free(zcache_obj_cache, obj);
- goto unlock_out;
- }
- preempt_disable();
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->obj == NULL)
- kp->obj = obj;
- else
- kmem_cache_free(zcache_obj_cache, obj);
- if (kp->page == NULL)
- kp->page = page;
- else
- free_page((unsigned long)page);
- ret = 0;
-unlock_out:
- spin_unlock(&zcache_direct_reclaim_lock);
-out:
- return ret;
-}
-
-static void *zcache_get_free_page(void)
-{
- struct zcache_preload *kp;
- void *page;
-
- kp = &__get_cpu_var(zcache_preloads);
- page = kp->page;
- BUG_ON(page == NULL);
- kp->page = NULL;
- return page;
-}
-
-static void zcache_free_page(void *p)
-{
- free_page((unsigned long)p);
-}
-
-/*
- * zcache implementation for tmem host ops
- */
-
-static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
-{
- struct tmem_objnode *objnode = NULL;
- unsigned long count;
- struct zcache_preload *kp;
-
- kp = &__get_cpu_var(zcache_preloads);
- if (kp->nr <= 0)
- goto out;
- objnode = kp->objnodes[kp->nr - 1];
- BUG_ON(objnode == NULL);
- kp->objnodes[kp->nr - 1] = NULL;
- kp->nr--;
- count = atomic_inc_return(&zcache_curr_objnode_count);
- if (count > zcache_curr_objnode_count_max)
- zcache_curr_objnode_count_max = count;
-out:
- return objnode;
-}
-
-static void zcache_objnode_free(struct tmem_objnode *objnode,
- struct tmem_pool *pool)
-{
- atomic_dec(&zcache_curr_objnode_count);
- BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
- kmem_cache_free(zcache_objnode_cache, objnode);
-}
-
-static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
-{
- struct tmem_obj *obj = NULL;
- unsigned long count;
- struct zcache_preload *kp;
-
- kp = &__get_cpu_var(zcache_preloads);
- obj = kp->obj;
- BUG_ON(obj == NULL);
- kp->obj = NULL;
- count = atomic_inc_return(&zcache_curr_obj_count);
- if (count > zcache_curr_obj_count_max)
- zcache_curr_obj_count_max = count;
- return obj;
-}
-
-static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
-{
- atomic_dec(&zcache_curr_obj_count);
- BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
- kmem_cache_free(zcache_obj_cache, obj);
-}
-
-static struct tmem_hostops zcache_hostops = {
- .obj_alloc = zcache_obj_alloc,
- .obj_free = zcache_obj_free,
- .objnode_alloc = zcache_objnode_alloc,
- .objnode_free = zcache_objnode_free,
-};
-
-/*
- * zcache implementations for PAM page descriptor ops
- */
-
-static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_eph_pampd_count_max;
-static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
-static unsigned long zcache_curr_pers_pampd_count_max;
-
-/* forward reference */
-static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
-
-static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
- struct tmem_pool *pool, struct tmem_oid *oid,
- uint32_t index)
-{
- void *pampd = NULL, *cdata;
- size_t clen;
- int ret;
- unsigned long count;
- struct page *page = virt_to_page(data);
- struct zcache_client *cli = pool->client;
- uint16_t client_id = get_client_id_from_client(cli);
- unsigned long zv_mean_zsize;
- unsigned long curr_pers_pampd_count;
-
- if (eph) {
- ret = zcache_compress(page, &cdata, &clen);
- if (ret == 0)
- goto out;
- if (clen == 0 || clen > zbud_max_buddy_size()) {
- zcache_compress_poor++;
- goto out;
- }
- pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
- index, page, cdata, clen);
- if (pampd != NULL) {
- count = atomic_inc_return(&zcache_curr_eph_pampd_count);
- if (count > zcache_curr_eph_pampd_count_max)
- zcache_curr_eph_pampd_count_max = count;
- }
- } else {
- curr_pers_pampd_count =
- atomic_read(&zcache_curr_pers_pampd_count);
- if (curr_pers_pampd_count >
- (zv_page_count_policy_percent * totalram_pages) / 100)
- goto out;
- ret = zcache_compress(page, &cdata, &clen);
- if (ret == 0)
- goto out;
- /* reject if compression is too poor */
- if (clen > zv_max_zsize) {
- zcache_compress_poor++;
- goto out;
- }
- /* reject if mean compression is too poor */
- if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
- zv_mean_zsize = xv_get_total_size_bytes(cli->xvpool) /
- curr_pers_pampd_count;
- if (zv_mean_zsize > zv_max_mean_zsize) {
- zcache_mean_compress_poor++;
- goto out;
- }
- }
- pampd = (void *)zv_create(cli->xvpool, pool->pool_id,
- oid, index, cdata, clen);
- if (pampd == NULL)
- goto out;
- count = atomic_inc_return(&zcache_curr_pers_pampd_count);
- if (count > zcache_curr_pers_pampd_count_max)
- zcache_curr_pers_pampd_count_max = count;
- }
-out:
- return pampd;
-}
-
-/*
- * fill the pageframe corresponding to the struct page with the data
- * from the passed pampd
- */
-static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
- void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- int ret = 0;
-
- BUG_ON(is_ephemeral(pool));
- zv_decompress(virt_to_page(data), pampd);
- return ret;
-}
-
-/*
- * fill the pageframe corresponding to the struct page with the data
- * from the passed pampd
- */
-static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
- void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- int ret = 0;
-
- BUG_ON(!is_ephemeral(pool));
- zbud_decompress(virt_to_page(data), pampd);
- zbud_free_and_delist((struct zbud_hdr *)pampd);
- atomic_dec(&zcache_curr_eph_pampd_count);
- return ret;
-}
-
-/*
- * free the pampd and remove it from any zcache lists
- * pampd must no longer be pointed to from any tmem data structures!
- */
-static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
- struct tmem_oid *oid, uint32_t index)
-{
- struct zcache_client *cli = pool->client;
-
- if (is_ephemeral(pool)) {
- zbud_free_and_delist((struct zbud_hdr *)pampd);
- atomic_dec(&zcache_curr_eph_pampd_count);
- BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
- } else {
- zv_free(cli->xvpool, (struct zv_hdr *)pampd);
- atomic_dec(&zcache_curr_pers_pampd_count);
- BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
- }
-}
-
-static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
-{
-}
-
-static void zcache_pampd_new_obj(struct tmem_obj *obj)
-{
-}
-
-static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
-{
- return -1;
-}
-
-static bool zcache_pampd_is_remote(void *pampd)
-{
- return 0;
-}
-
-static struct tmem_pamops zcache_pamops = {
- .create = zcache_pampd_create,
- .get_data = zcache_pampd_get_data,
- .get_data_and_free = zcache_pampd_get_data_and_free,
- .free = zcache_pampd_free,
- .free_obj = zcache_pampd_free_obj,
- .new_obj = zcache_pampd_new_obj,
- .replace_in_obj = zcache_pampd_replace_in_obj,
- .is_remote = zcache_pampd_is_remote,
-};
-
-/*
- * zcache compression/decompression and related per-cpu stuff
- */
-
-#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
-#define LZO_DSTMEM_PAGE_ORDER 1
-static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
-static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
-
-static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
-{
- int ret = 0;
- unsigned char *dmem = __get_cpu_var(zcache_dstmem);
- unsigned char *wmem = __get_cpu_var(zcache_workmem);
- char *from_va;
-
- BUG_ON(!irqs_disabled());
- if (unlikely(dmem == NULL || wmem == NULL))
- goto out; /* no buffer, so can't compress */
- from_va = kmap_atomic(from, KM_USER0);
- mb();
- ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
- BUG_ON(ret != LZO_E_OK);
- *out_va = dmem;
- kunmap_atomic(from_va, KM_USER0);
- ret = 1;
-out:
- return ret;
-}
-
-
-static int zcache_cpu_notifier(struct notifier_block *nb,
- unsigned long action, void *pcpu)
-{
- int cpu = (long)pcpu;
- struct zcache_preload *kp;
-
- switch (action) {
- case CPU_UP_PREPARE:
- per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
- GFP_KERNEL | __GFP_REPEAT,
- LZO_DSTMEM_PAGE_ORDER),
- per_cpu(zcache_workmem, cpu) =
- kzalloc(LZO1X_MEM_COMPRESS,
- GFP_KERNEL | __GFP_REPEAT);
- break;
- case CPU_DEAD:
- case CPU_UP_CANCELED:
- free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
- LZO_DSTMEM_PAGE_ORDER);
- per_cpu(zcache_dstmem, cpu) = NULL;
- kfree(per_cpu(zcache_workmem, cpu));
- per_cpu(zcache_workmem, cpu) = NULL;
- kp = &per_cpu(zcache_preloads, cpu);
- while (kp->nr) {
- kmem_cache_free(zcache_objnode_cache,
- kp->objnodes[kp->nr - 1]);
- kp->objnodes[kp->nr - 1] = NULL;
- kp->nr--;
- }
- kmem_cache_free(zcache_obj_cache, kp->obj);
- free_page((unsigned long)kp->page);
- break;
- default:
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block zcache_cpu_notifier_block = {
- .notifier_call = zcache_cpu_notifier
-};
-
-#ifdef CONFIG_SYSFS
-#define ZCACHE_SYSFS_RO(_name) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return sprintf(buf, "%lu\n", zcache_##_name); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
- static ssize_t zcache_##_name##_show(struct kobject *kobj, \
- struct kobj_attribute *attr, char *buf) \
- { \
- return _func(buf); \
- } \
- static struct kobj_attribute zcache_##_name##_attr = { \
- .attr = { .name = __stringify(_name), .mode = 0444 }, \
- .show = zcache_##_name##_show, \
- }
-
-ZCACHE_SYSFS_RO(curr_obj_count_max);
-ZCACHE_SYSFS_RO(curr_objnode_count_max);
-ZCACHE_SYSFS_RO(flush_total);
-ZCACHE_SYSFS_RO(flush_found);
-ZCACHE_SYSFS_RO(flobj_total);
-ZCACHE_SYSFS_RO(flobj_found);
-ZCACHE_SYSFS_RO(failed_eph_puts);
-ZCACHE_SYSFS_RO(failed_pers_puts);
-ZCACHE_SYSFS_RO(zbud_curr_zbytes);
-ZCACHE_SYSFS_RO(zbud_cumul_zpages);
-ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
-ZCACHE_SYSFS_RO(zbud_buddied_count);
-ZCACHE_SYSFS_RO(zbpg_unused_list_count);
-ZCACHE_SYSFS_RO(evicted_raw_pages);
-ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
-ZCACHE_SYSFS_RO(evicted_buddied_pages);
-ZCACHE_SYSFS_RO(failed_get_free_pages);
-ZCACHE_SYSFS_RO(failed_alloc);
-ZCACHE_SYSFS_RO(put_to_flush);
-ZCACHE_SYSFS_RO(aborted_preload);
-ZCACHE_SYSFS_RO(aborted_shrink);
-ZCACHE_SYSFS_RO(compress_poor);
-ZCACHE_SYSFS_RO(mean_compress_poor);
-ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
-ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
-ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
-ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
-ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
- zbud_show_unbuddied_list_counts);
-ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
- zbud_show_cumul_chunk_counts);
-ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
- zv_curr_dist_counts_show);
-ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
- zv_cumul_dist_counts_show);
-
-static struct attribute *zcache_attrs[] = {
- &zcache_curr_obj_count_attr.attr,
- &zcache_curr_obj_count_max_attr.attr,
- &zcache_curr_objnode_count_attr.attr,
- &zcache_curr_objnode_count_max_attr.attr,
- &zcache_flush_total_attr.attr,
- &zcache_flobj_total_attr.attr,
- &zcache_flush_found_attr.attr,
- &zcache_flobj_found_attr.attr,
- &zcache_failed_eph_puts_attr.attr,
- &zcache_failed_pers_puts_attr.attr,
- &zcache_compress_poor_attr.attr,
- &zcache_mean_compress_poor_attr.attr,
- &zcache_zbud_curr_raw_pages_attr.attr,
- &zcache_zbud_curr_zpages_attr.attr,
- &zcache_zbud_curr_zbytes_attr.attr,
- &zcache_zbud_cumul_zpages_attr.attr,
- &zcache_zbud_cumul_zbytes_attr.attr,
- &zcache_zbud_buddied_count_attr.attr,
- &zcache_zbpg_unused_list_count_attr.attr,
- &zcache_evicted_raw_pages_attr.attr,
- &zcache_evicted_unbuddied_pages_attr.attr,
- &zcache_evicted_buddied_pages_attr.attr,
- &zcache_failed_get_free_pages_attr.attr,
- &zcache_failed_alloc_attr.attr,
- &zcache_put_to_flush_attr.attr,
- &zcache_aborted_preload_attr.attr,
- &zcache_aborted_shrink_attr.attr,
- &zcache_zbud_unbuddied_list_counts_attr.attr,
- &zcache_zbud_cumul_chunk_counts_attr.attr,
- &zcache_zv_curr_dist_counts_attr.attr,
- &zcache_zv_cumul_dist_counts_attr.attr,
- &zcache_zv_max_zsize_attr.attr,
- &zcache_zv_max_mean_zsize_attr.attr,
- &zcache_zv_page_count_policy_percent_attr.attr,
- NULL,
-};
-
-static struct attribute_group zcache_attr_group = {
- .attrs = zcache_attrs,
- .name = "zcache",
-};
-
-#endif /* CONFIG_SYSFS */
-/*
- * When zcache is disabled ("frozen"), pools can be created and destroyed,
- * but all puts (and thus all other operations that require memory allocation)
- * must fail. If zcache is unfrozen, accepts puts, then frozen again,
- * data consistency requires all puts while frozen to be converted into
- * flushes.
- */
-static bool zcache_freeze;
-
-/*
- * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
- */
-static int shrink_zcache_memory(struct shrinker *shrink,
- struct shrink_control *sc)
-{
- int ret = -1;
- int nr = sc->nr_to_scan;
- gfp_t gfp_mask = sc->gfp_mask;
-
- if (nr >= 0) {
- if (!(gfp_mask & __GFP_FS))
- /* does this case really need to be skipped? */
- goto out;
- if (spin_trylock(&zcache_direct_reclaim_lock)) {
- zbud_evict_pages(nr);
- spin_unlock(&zcache_direct_reclaim_lock);
- } else
- zcache_aborted_shrink++;
- }
- ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
-out:
- return ret;
-}
-
-static struct shrinker zcache_shrinker = {
- .shrink = shrink_zcache_memory,
- .seeks = DEFAULT_SEEKS,
-};
-
-/*
- * zcache shims between cleancache/frontswap ops and tmem
- */
-
-static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
- uint32_t index, struct page *page)
-{
- struct tmem_pool *pool;
- int ret = -1;
-
- BUG_ON(!irqs_disabled());
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (unlikely(pool == NULL))
- goto out;
- if (!zcache_freeze && zcache_do_preload(pool) == 0) {
- /* preload does preempt_disable on success */
- ret = tmem_put(pool, oidp, index, page_address(page),
- PAGE_SIZE, 0, is_ephemeral(pool));
- if (ret < 0) {
- if (is_ephemeral(pool))
- zcache_failed_eph_puts++;
- else
- zcache_failed_pers_puts++;
- }
- zcache_put_pool(pool);
- preempt_enable_no_resched();
- } else {
- zcache_put_to_flush++;
- if (atomic_read(&pool->obj_count) > 0)
- /* the put fails whether the flush succeeds or not */
- (void)tmem_flush_page(pool, oidp, index);
- zcache_put_pool(pool);
- }
-out:
- return ret;
-}
-
-static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
- uint32_t index, struct page *page)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
- size_t size = PAGE_SIZE;
-
- local_irq_save(flags);
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_get(pool, oidp, index, page_address(page),
- &size, 0, is_ephemeral(pool));
- zcache_put_pool(pool);
- }
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_flush_page(int cli_id, int pool_id,
- struct tmem_oid *oidp, uint32_t index)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
-
- local_irq_save(flags);
- zcache_flush_total++;
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_flush_page(pool, oidp, index);
- zcache_put_pool(pool);
- }
- if (ret >= 0)
- zcache_flush_found++;
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_flush_object(int cli_id, int pool_id,
- struct tmem_oid *oidp)
-{
- struct tmem_pool *pool;
- int ret = -1;
- unsigned long flags;
-
- local_irq_save(flags);
- zcache_flobj_total++;
- pool = zcache_get_pool_by_id(cli_id, pool_id);
- if (likely(pool != NULL)) {
- if (atomic_read(&pool->obj_count) > 0)
- ret = tmem_flush_object(pool, oidp);
- zcache_put_pool(pool);
- }
- if (ret >= 0)
- zcache_flobj_found++;
- local_irq_restore(flags);
- return ret;
-}
-
-static int zcache_destroy_pool(int cli_id, int pool_id)
-{
- struct tmem_pool *pool = NULL;
- struct zcache_client *cli = NULL;
- int ret = -1;
-
- if (pool_id < 0)
- goto out;
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- pool = cli->tmem_pools[pool_id];
- if (pool == NULL)
- goto out;
- cli->tmem_pools[pool_id] = NULL;
- /* wait for pool activity on other cpus to quiesce */
- while (atomic_read(&pool->refcount) != 0)
- ;
- atomic_dec(&cli->refcount);
- local_bh_disable();
- ret = tmem_destroy_pool(pool);
- local_bh_enable();
- kfree(pool);
- pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
- pool_id, cli_id);
-out:
- return ret;
-}
-
-static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
-{
- int poolid = -1;
- struct tmem_pool *pool;
- struct zcache_client *cli = NULL;
-
- if (cli_id == LOCAL_CLIENT)
- cli = &zcache_host;
- else if ((unsigned int)cli_id < MAX_CLIENTS)
- cli = &zcache_clients[cli_id];
- if (cli == NULL)
- goto out;
- atomic_inc(&cli->refcount);
- pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
- if (pool == NULL) {
- pr_info("zcache: pool creation failed: out of memory\n");
- goto out;
- }
-
- for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
- if (cli->tmem_pools[poolid] == NULL)
- break;
- if (poolid >= MAX_POOLS_PER_CLIENT) {
- pr_info("zcache: pool creation failed: max exceeded\n");
- kfree(pool);
- poolid = -1;
- goto out;
- }
- atomic_set(&pool->refcount, 0);
- pool->client = cli;
- pool->pool_id = poolid;
- tmem_new_pool(pool, flags);
- cli->tmem_pools[poolid] = pool;
- pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
- flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
- poolid, cli_id);
-out:
- if (cli != NULL)
- atomic_dec(&cli->refcount);
- return poolid;
-}
-
-/**********
- * Two kernel functionalities currently can be layered on top of tmem.
- * These are "cleancache" which is used as a second-chance cache for clean
- * page cache pages; and "frontswap" which is used for swap pages
- * to avoid writes to disk. A generic "shim" is provided here for each
- * to translate in-kernel semantics to zcache semantics.
- */
-
-#ifdef CONFIG_CLEANCACHE
-static void zcache_cleancache_put_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (likely(ind == index))
- (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
-}
-
-static int zcache_cleancache_get_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
- int ret = -1;
-
- if (likely(ind == index))
- ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
- return ret;
-}
-
-static void zcache_cleancache_flush_page(int pool_id,
- struct cleancache_filekey key,
- pgoff_t index)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (likely(ind == index))
- (void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
-}
-
-static void zcache_cleancache_flush_inode(int pool_id,
- struct cleancache_filekey key)
-{
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
-}
-
-static void zcache_cleancache_flush_fs(int pool_id)
-{
- if (pool_id >= 0)
- (void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
-}
-
-static int zcache_cleancache_init_fs(size_t pagesize)
-{
- BUG_ON(sizeof(struct cleancache_filekey) !=
- sizeof(struct tmem_oid));
- BUG_ON(pagesize != PAGE_SIZE);
- return zcache_new_pool(LOCAL_CLIENT, 0);
-}
-
-static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
-{
- /* shared pools are unsupported and map to private */
- BUG_ON(sizeof(struct cleancache_filekey) !=
- sizeof(struct tmem_oid));
- BUG_ON(pagesize != PAGE_SIZE);
- return zcache_new_pool(LOCAL_CLIENT, 0);
-}
-
-static struct cleancache_ops zcache_cleancache_ops = {
- .put_page = zcache_cleancache_put_page,
- .get_page = zcache_cleancache_get_page,
- .flush_page = zcache_cleancache_flush_page,
- .flush_inode = zcache_cleancache_flush_inode,
- .flush_fs = zcache_cleancache_flush_fs,
- .init_shared_fs = zcache_cleancache_init_shared_fs,
- .init_fs = zcache_cleancache_init_fs
-};
-
-struct cleancache_ops zcache_cleancache_register_ops(void)
-{
- struct cleancache_ops old_ops =
- cleancache_register_ops(&zcache_cleancache_ops);
-
- return old_ops;
-}
-#endif
-
-#ifdef CONFIG_FRONTSWAP
-/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
-static int zcache_frontswap_poolid = -1;
-
-/*
- * Swizzling increases objects per swaptype, increasing tmem concurrency
- * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
- */
-#define SWIZ_BITS 4
-#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
-#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
-#define iswiz(_ind) (_ind >> SWIZ_BITS)
-
-static inline struct tmem_oid oswiz(unsigned type, u32 ind)
-{
- struct tmem_oid oid = { .oid = { 0 } };
- oid.oid[0] = _oswiz(type, ind);
- return oid;
-}
-
-static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
- int ret = -1;
- unsigned long flags;
-
- BUG_ON(!PageLocked(page));
- if (likely(ind64 == ind)) {
- local_irq_save(flags);
- ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind), page);
- local_irq_restore(flags);
- }
- return ret;
-}
-
-/* returns 0 if the page was successfully gotten from frontswap, -1 if
- * was not present (should never happen!) */
-static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
- int ret = -1;
-
- BUG_ON(!PageLocked(page));
- if (likely(ind64 == ind))
- ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind), page);
- return ret;
-}
-
-/* flush a single page from frontswap */
-static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- struct tmem_oid oid = oswiz(type, ind);
-
- if (likely(ind64 == ind))
- (void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
- &oid, iswiz(ind));
-}
-
-/* flush all pages from the passed swaptype */
-static void zcache_frontswap_flush_area(unsigned type)
-{
- struct tmem_oid oid;
- int ind;
-
- for (ind = SWIZ_MASK; ind >= 0; ind--) {
- oid = oswiz(type, ind);
- (void)zcache_flush_object(LOCAL_CLIENT,
- zcache_frontswap_poolid, &oid);
- }
-}
-
-static void zcache_frontswap_init(unsigned ignored)
-{
- /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
- if (zcache_frontswap_poolid < 0)
- zcache_frontswap_poolid =
- zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
-}
-
-static struct frontswap_ops zcache_frontswap_ops = {
- .put_page = zcache_frontswap_put_page,
- .get_page = zcache_frontswap_get_page,
- .flush_page = zcache_frontswap_flush_page,
- .flush_area = zcache_frontswap_flush_area,
- .init = zcache_frontswap_init
-};
-
-struct frontswap_ops zcache_frontswap_register_ops(void)
-{
- struct frontswap_ops old_ops =
- frontswap_register_ops(&zcache_frontswap_ops);
-
- return old_ops;
-}
-#endif
-
-/*
- * zcache initialization
- * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
- * NOTHING HAPPENS!
- */
-
-static int zcache_enabled;
-
-static int __init enable_zcache(char *s)
-{
- zcache_enabled = 1;
- return 1;
-}
-__setup("zcache", enable_zcache);
-
-/* allow independent dynamic disabling of cleancache and frontswap */
-
-static int use_cleancache = 1;
-
-static int __init no_cleancache(char *s)
-{
- use_cleancache = 0;
- return 1;
-}
-
-__setup("nocleancache", no_cleancache);
-
-static int use_frontswap = 1;
-
-static int __init no_frontswap(char *s)
-{
- use_frontswap = 0;
- return 1;
-}
-
-__setup("nofrontswap", no_frontswap);
-
-static int __init zcache_init(void)
-{
-#ifdef CONFIG_SYSFS
- int ret = 0;
-
- ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
- if (ret) {
- pr_err("zcache: can't create sysfs\n");
- goto out;
- }
-#endif /* CONFIG_SYSFS */
-#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
- if (zcache_enabled) {
- unsigned int cpu;
-
- tmem_register_hostops(&zcache_hostops);
- tmem_register_pamops(&zcache_pamops);
- ret = register_cpu_notifier(&zcache_cpu_notifier_block);
- if (ret) {
- pr_err("zcache: can't register cpu notifier\n");
- goto out;
- }
- for_each_online_cpu(cpu) {
- void *pcpu = (void *)(long)cpu;
- zcache_cpu_notifier(&zcache_cpu_notifier_block,
- CPU_UP_PREPARE, pcpu);
- }
- }
- zcache_objnode_cache = kmem_cache_create("zcache_objnode",
- sizeof(struct tmem_objnode), 0, 0, NULL);
- zcache_obj_cache = kmem_cache_create("zcache_obj",
- sizeof(struct tmem_obj), 0, 0, NULL);
- ret = zcache_new_client(LOCAL_CLIENT);
- if (ret) {
- pr_err("zcache: can't create client\n");
- goto out;
- }
-#endif
-#ifdef CONFIG_CLEANCACHE
- if (zcache_enabled && use_cleancache) {
- struct cleancache_ops old_ops;
-
- zbud_init();
- register_shrinker(&zcache_shrinker);
- old_ops = zcache_cleancache_register_ops();
- pr_info("zcache: cleancache enabled using kernel "
- "transcendent memory and compression buddies\n");
- if (old_ops.init_fs != NULL)
- pr_warning("zcache: cleancache_ops overridden");
- }
-#endif
-#ifdef CONFIG_FRONTSWAP
- if (zcache_enabled && use_frontswap) {
- struct frontswap_ops old_ops;
-
- old_ops = zcache_frontswap_register_ops();
- pr_info("zcache: frontswap enabled using kernel "
- "transcendent memory and xvmalloc\n");
- if (old_ops.init != NULL)
- pr_warning("ktmem: frontswap_ops overridden");
- }
-#endif
-out:
- return ret;
-}
-
-module_init(zcache_init)
--
1.7.5.4


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