lkml.org 
[lkml]   [2011]   [Sep]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[patch 10/10] mm: memcg: remove unused node/section info from pc->flags
Date
To find the page corresponding to a certain page_cgroup, the pc->flags
encoded the node or section ID with the base array to compare the pc
pointer to.

Now that the per-memory cgroup LRU lists link page descriptors
directly, there is no longer any code that knows the struct
page_cgroup of a PFN but not the struct page.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
---
include/linux/page_cgroup.h | 33 ------------------------
mm/page_cgroup.c | 58 ++++++-------------------------------------
2 files changed, 8 insertions(+), 83 deletions(-)
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 5bae753..aaa60da 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -121,39 +121,6 @@ static inline void move_unlock_page_cgroup(struct page_cgroup *pc,
local_irq_restore(*flags);
}

-#ifdef CONFIG_SPARSEMEM
-#define PCG_ARRAYID_WIDTH SECTIONS_SHIFT
-#else
-#define PCG_ARRAYID_WIDTH NODES_SHIFT
-#endif
-
-#if (PCG_ARRAYID_WIDTH > BITS_PER_LONG - NR_PCG_FLAGS)
-#error Not enough space left in pc->flags to store page_cgroup array IDs
-#endif
-
-/* pc->flags: ARRAY-ID | FLAGS */
-
-#define PCG_ARRAYID_MASK ((1UL << PCG_ARRAYID_WIDTH) - 1)
-
-#define PCG_ARRAYID_OFFSET (BITS_PER_LONG - PCG_ARRAYID_WIDTH)
-/*
- * Zero the shift count for non-existent fields, to prevent compiler
- * warnings and ensure references are optimized away.
- */
-#define PCG_ARRAYID_SHIFT (PCG_ARRAYID_OFFSET * (PCG_ARRAYID_WIDTH != 0))
-
-static inline void set_page_cgroup_array_id(struct page_cgroup *pc,
- unsigned long id)
-{
- pc->flags &= ~(PCG_ARRAYID_MASK << PCG_ARRAYID_SHIFT);
- pc->flags |= (id & PCG_ARRAYID_MASK) << PCG_ARRAYID_SHIFT;
-}
-
-static inline unsigned long page_cgroup_array_id(struct page_cgroup *pc)
-{
- return (pc->flags >> PCG_ARRAYID_SHIFT) & PCG_ARRAYID_MASK;
-}
-
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct page_cgroup;

diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 256dee8..2601a65 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -11,12 +11,6 @@
#include <linux/swapops.h>
#include <linux/kmemleak.h>

-static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)
-{
- pc->flags = 0;
- set_page_cgroup_array_id(pc, id);
- pc->mem_cgroup = NULL;
-}
static unsigned long total_usage;

#if !defined(CONFIG_SPARSEMEM)
@@ -41,24 +35,11 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
return base + offset;
}

-struct page *lookup_cgroup_page(struct page_cgroup *pc)
-{
- unsigned long pfn;
- struct page *page;
- pg_data_t *pgdat;
-
- pgdat = NODE_DATA(page_cgroup_array_id(pc));
- pfn = pc - pgdat->node_page_cgroup + pgdat->node_start_pfn;
- page = pfn_to_page(pfn);
- VM_BUG_ON(pc != lookup_page_cgroup(page));
- return page;
-}
-
static int __init alloc_node_page_cgroup(int nid)
{
- struct page_cgroup *base, *pc;
+ struct page_cgroup *base;
unsigned long table_size;
- unsigned long start_pfn, nr_pages, index;
+ unsigned long nr_pages;

start_pfn = NODE_DATA(nid)->node_start_pfn;
nr_pages = NODE_DATA(nid)->node_spanned_pages;
@@ -72,10 +53,6 @@ static int __init alloc_node_page_cgroup(int nid)
table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
if (!base)
return -ENOMEM;
- for (index = 0; index < nr_pages; index++) {
- pc = base + index;
- init_page_cgroup(pc, nid);
- }
NODE_DATA(nid)->node_page_cgroup = base;
total_usage += table_size;
return 0;
@@ -116,31 +93,19 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
return section->page_cgroup + pfn;
}

-struct page *lookup_cgroup_page(struct page_cgroup *pc)
-{
- struct mem_section *section;
- struct page *page;
- unsigned long nr;
-
- nr = page_cgroup_array_id(pc);
- section = __nr_to_section(nr);
- page = pfn_to_page(pc - section->page_cgroup);
- VM_BUG_ON(pc != lookup_page_cgroup(page));
- return page;
-}
-
static void *__meminit alloc_page_cgroup(size_t size, int nid)
{
void *addr = NULL;

- addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN);
+ addr = alloc_pages_exact_nid(nid, size,
+ GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
if (addr)
return addr;

if (node_state(nid, N_HIGH_MEMORY))
- addr = vmalloc_node(size, nid);
+ addr = vzalloc_node(size, nid);
else
- addr = vmalloc(size);
+ addr = vzalloc(size);

return addr;
}
@@ -163,14 +128,11 @@ static void free_page_cgroup(void *addr)

static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
{
- struct page_cgroup *base, *pc;
struct mem_section *section;
+ struct page_cgroup *base;
unsigned long table_size;
- unsigned long nr;
- int index;

- nr = pfn_to_section_nr(pfn);
- section = __nr_to_section(nr);
+ section = __pfn_to_section(pfn);

if (section->page_cgroup)
return 0;
@@ -190,10 +152,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
return -ENOMEM;
}

- for (index = 0; index < PAGES_PER_SECTION; index++) {
- pc = base + index;
- init_page_cgroup(pc, nr);
- }
/*
* The passed "pfn" may not be aligned to SECTION. For the calculation
* we need to apply a mask.
--
1.7.6.2


\
 
 \ /
  Last update: 2011-09-29 23:05    [from the cache]
©2003-2011 Jasper Spaans