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Subject[PATCH v5 4/7] mm: rework __isolate_lru_page() page lru filter
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This patch adds lru bit mask into lower byte of isolate_mode_t,
this allows to simplify checks in __isolate_lru_page().

v5:
* lru bit mask instead of special file/anon active/inactive bits
* mark page_lru() as __always_inline, it helps gcc generate more compact code

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>

---
add/remove: 0/0 grow/shrink: 3/4 up/down: 35/-67 (-32)
function old new delta
static.shrink_active_list 837 853 +16
__isolate_lru_page 301 317 +16
page_evictable 170 173 +3
__remove_mapping 322 319 -3
mem_cgroup_lru_del 73 65 -8
static.isolate_lru_pages 1055 1035 -20
__mem_cgroup_commit_charge 676 640 -36
---
include/linux/mm_inline.h | 2 +-
include/linux/mmzone.h | 12 +++++-------
include/linux/swap.h | 2 +-
mm/compaction.c | 4 ++--
mm/vmscan.c | 44 +++++++++++++++-----------------------------
5 files changed, 24 insertions(+), 40 deletions(-)
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 227fd3e..71e7d76 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -85,7 +85,7 @@ static inline enum lru_list page_off_lru(struct page *page)
* Returns the LRU list a page should be on, as an index
* into the array of LRU lists.
*/
-static inline enum lru_list page_lru(struct page *page)
+static __always_inline enum lru_list page_lru(struct page *page)
{
enum lru_list lru;

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aa881de..3370a8c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -183,16 +183,14 @@ struct lruvec {
#define LRU_ALL_EVICTABLE (LRU_ALL_FILE | LRU_ALL_ANON)
#define LRU_ALL ((1 << NR_LRU_LISTS) - 1)

-/* Isolate inactive pages */
-#define ISOLATE_INACTIVE ((__force isolate_mode_t)0x1)
-/* Isolate active pages */
-#define ISOLATE_ACTIVE ((__force isolate_mode_t)0x2)
+/* Mask of LRU lists allowed for isolation */
+#define ISOLATE_LRU_MASK ((__force isolate_mode_t)0xFF)
/* Isolate clean file */
-#define ISOLATE_CLEAN ((__force isolate_mode_t)0x4)
+#define ISOLATE_CLEAN ((__force isolate_mode_t)0x100)
/* Isolate unmapped file */
-#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8)
+#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x200)
/* Isolate for asynchronous migration */
-#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x10)
+#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x400)

/* LRU Isolation modes. */
typedef unsigned __bitwise__ isolate_mode_t;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index ba2c8d7..dc6e6a3 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -254,7 +254,7 @@ static inline void lru_cache_add_file(struct page *page)
/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
-extern int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file);
+extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap);
extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
diff --git a/mm/compaction.c b/mm/compaction.c
index 74a8c82..5b02dbd 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -261,7 +261,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
unsigned long last_pageblock_nr = 0, pageblock_nr;
unsigned long nr_scanned = 0, nr_isolated = 0;
struct list_head *migratelist = &cc->migratepages;
- isolate_mode_t mode = ISOLATE_ACTIVE|ISOLATE_INACTIVE;
+ isolate_mode_t mode = LRU_ALL_EVICTABLE;

/* Do not scan outside zone boundaries */
low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
@@ -375,7 +375,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
mode |= ISOLATE_ASYNC_MIGRATE;

/* Try isolate the page */
- if (__isolate_lru_page(page, mode, 0) != 0)
+ if (__isolate_lru_page(page, mode) != 0)
continue;

VM_BUG_ON(PageTransCompound(page));
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9769970..0966f11 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1028,36 +1028,20 @@ keep_lumpy:
*
* returns 0 on success, -ve errno on failure.
*/
-int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
+int __isolate_lru_page(struct page *page, isolate_mode_t mode)
{
- bool all_lru_mode;
int ret = -EINVAL;

/* Only take pages on the LRU. */
if (!PageLRU(page))
return ret;

- all_lru_mode = (mode & (ISOLATE_ACTIVE|ISOLATE_INACTIVE)) ==
- (ISOLATE_ACTIVE|ISOLATE_INACTIVE);
-
- /*
- * When checking the active state, we need to be sure we are
- * dealing with comparible boolean values. Take the logical not
- * of each.
- */
- if (!all_lru_mode && !PageActive(page) != !(mode & ISOLATE_ACTIVE))
+ /* Isolate pages only from allowed LRU lists */
+ if (!(mode & BIT(page_lru(page))))
return ret;

- if (!all_lru_mode && !!page_is_file_cache(page) != file)
- return ret;
-
- /*
- * When this function is being called for lumpy reclaim, we
- * initially look into all LRU pages, active, inactive and
- * unevictable; only give shrink_page_list evictable pages.
- */
- if (PageUnevictable(page))
- return ret;
+ /* All possible LRU lists must fit into isolation mask area */
+ BUILD_BUG_ON(LRU_ALL & ~ISOLATE_LRU_MASK);

ret = -EBUSY;

@@ -1160,7 +1144,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,

VM_BUG_ON(!PageLRU(page));

- switch (__isolate_lru_page(page, mode, file)) {
+ switch (__isolate_lru_page(page, mode)) {
case 0:
mem_cgroup_lru_del(page);
list_move(&page->lru, dst);
@@ -1218,7 +1202,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
!PageSwapCache(cursor_page))
break;

- if (__isolate_lru_page(cursor_page, mode, file) == 0) {
+ if (__isolate_lru_page(cursor_page, mode) == 0) {
unsigned int isolated_pages;

mem_cgroup_lru_del(cursor_page);
@@ -1492,7 +1476,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
unsigned long nr_file;
unsigned long nr_dirty = 0;
unsigned long nr_writeback = 0;
- isolate_mode_t isolate_mode = ISOLATE_INACTIVE;
+ isolate_mode_t isolate_mode;
int file = is_file_lru(lru);
struct zone *zone = mz->zone;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
@@ -1505,12 +1489,13 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
return SWAP_CLUSTER_MAX;
}

- set_reclaim_mode(priority, sc, false);
- if (sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM)
- isolate_mode |= ISOLATE_ACTIVE;
-
lru_add_drain();

+ set_reclaim_mode(priority, sc, false);
+
+ isolate_mode = BIT(lru);
+ if (sc->reclaim_mode & RECLAIM_MODE_LUMPYRECLAIM)
+ isolate_mode |= LRU_ALL_EVICTABLE;
if (!sc->may_unmap)
isolate_mode |= ISOLATE_UNMAPPED;
if (!sc->may_writepage)
@@ -1668,12 +1653,13 @@ static void shrink_active_list(unsigned long nr_to_scan,
struct page *page;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
unsigned long nr_rotated = 0;
- isolate_mode_t isolate_mode = ISOLATE_ACTIVE;
+ isolate_mode_t isolate_mode;
int file = is_file_lru(lru);
struct zone *zone = mz->zone;

lru_add_drain();

+ isolate_mode = BIT(lru);
if (!sc->may_unmap)
isolate_mode |= ISOLATE_UNMAPPED;
if (!sc->may_writepage)


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