The patch titled
memcg: remove refcnt from page_cgroup
has been added to the -mm tree. Its filename is
memcg-remove-refcnt-from-page_cgroup.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg: remove refcnt from page_cgroup
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
memcg: performance improvements
Patch Description
1/5 ... remove refcnt fron page_cgroup patch (shmem handling is fixed)
2/5 ... swapcache handling patch
3/5 ... add helper function for shmem's memory reclaim patch
4/5 ... optimize by likely/unlikely ppatch
5/5 ... remove redundunt check patch (shmem handling is fixed.)
Unix bench result.
== 2.6.26-rc2-mm1 + memory resource controller
Execl Throughput 2915.4 lps (29.6 secs, 3 samples)
C Compiler Throughput 1019.3 lpm (60.0 secs, 3 samples)
Shell Scripts (1 concurrent) 5796.0 lpm (60.0 secs, 3 samples)
Shell Scripts (8 concurrent) 1097.7 lpm (60.0 secs, 3 samples)
Shell Scripts (16 concurrent) 565.3 lpm (60.0 secs, 3 samples)
File Read 1024 bufsize 2000 maxblocks 1022128.0 KBps (30.0 secs, 3 samples)
File Write 1024 bufsize 2000 maxblocks 544057.0 KBps (30.0 secs, 3 samples)
File Copy 1024 bufsize 2000 maxblocks 346481.0 KBps (30.0 secs, 3 samples)
File Read 256 bufsize 500 maxblocks 319325.0 KBps (30.0 secs, 3 samples)
File Write 256 bufsize 500 maxblocks 148788.0 KBps (30.0 secs, 3 samples)
File Copy 256 bufsize 500 maxblocks 99051.0 KBps (30.0 secs, 3 samples)
File Read 4096 bufsize 8000 maxblocks 2058917.0 KBps (30.0 secs, 3 samples)
File Write 4096 bufsize 8000 maxblocks 1606109.0 KBps (30.0 secs, 3 samples)
File Copy 4096 bufsize 8000 maxblocks 854789.0 KBps (30.0 secs, 3 samples)
Dc: sqrt(2) to 99 decimal places 126145.2 lpm (30.0 secs, 3 samples)
INDEX VALUES
TEST BASELINE RESULT INDEX
Execl Throughput 43.0 2915.4 678.0
File Copy 1024 bufsize 2000 maxblocks 3960.0 346481.0 875.0
File Copy 256 bufsize 500 maxblocks 1655.0 99051.0 598.5
File Copy 4096 bufsize 8000 maxblocks 5800.0 854789.0 1473.8
Shell Scripts (8 concurrent) 6.0 1097.7 1829.5
=========
FINAL SCORE 991.3
== 2.6.26-rc2-mm1 + this set ==
Execl Throughput 3012.9 lps (29.9 secs, 3 samples)
C Compiler Throughput 981.0 lpm (60.0 secs, 3 samples)
Shell Scripts (1 concurrent) 5872.0 lpm (60.0 secs, 3 samples)
Shell Scripts (8 concurrent) 1120.3 lpm (60.0 secs, 3 samples)
Shell Scripts (16 concurrent) 578.0 lpm (60.0 secs, 3 samples)
File Read 1024 bufsize 2000 maxblocks 1003993.0 KBps (30.0 secs, 3 samples)
File Write 1024 bufsize 2000 maxblocks 550452.0 KBps (30.0 secs, 3 samples)
File Copy 1024 bufsize 2000 maxblocks 347159.0 KBps (30.0 secs, 3 samples)
File Read 256 bufsize 500 maxblocks 314644.0 KBps (30.0 secs, 3 samples)
File Write 256 bufsize 500 maxblocks 151852.0 KBps (30.0 secs, 3 samples)
File Copy 256 bufsize 500 maxblocks 101000.0 KBps (30.0 secs, 3 samples)
File Read 4096 bufsize 8000 maxblocks 2033256.0 KBps (30.0 secs, 3 samples)
File Write 4096 bufsize 8000 maxblocks 1611814.0 KBps (30.0 secs, 3 samples)
File Copy 4096 bufsize 8000 maxblocks 847979.0 KBps (30.0 secs, 3 samples)
Dc: sqrt(2) to 99 decimal places 128148.7 lpm (30.0 secs, 3 samples)
INDEX VALUES
TEST BASELINE RESULT INDEX
Execl Throughput 43.0 3012.9 700.7
File Copy 1024 bufsize 2000 maxblocks 3960.0 347159.0 876.7
File Copy 256 bufsize 500 maxblocks 1655.0 101000.0 610.3
File Copy 4096 bufsize 8000 maxblocks 5800.0 847979.0 1462.0
Shell Scripts (8 concurrent) 6.0 1120.3 1867.2
=========
FINAL SCORE 1004.6
This patch:
Remove refcnt from page_cgroup().
After this,
* A page is charged only when !page_mapped() && no page_cgroup is assigned.
* Anon page is newly mapped.
* File page is added to mapping->tree.
* A page is uncharged only when
* Anon page is fully unmapped.
* File page is removed from LRU.
There is no change in behavior from user's view.
This patch also removes unnecessary calls in rmap.c which was used only for
refcnt mangement.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 10 +--
mm/filemap.c | 6 +-
mm/memcontrol.c | 97 ++++++++++++++++++-----------------
mm/migrate.c | 3 -
mm/rmap.c | 14 -----
mm/shmem.c | 42 ++++++++++-----
6 files changed, 90 insertions(+), 82 deletions(-)
diff -puN include/linux/memcontrol.h~memcg-remove-refcnt-from-page_cgroup include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~memcg-remove-refcnt-from-page_cgroup
+++ a/include/linux/memcontrol.h
@@ -35,6 +35,7 @@ extern int mem_cgroup_charge(struct page
extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
extern void mem_cgroup_uncharge_page(struct page *page);
+extern void mem_cgroup_uncharge_cache_page(struct page *page);
extern void mem_cgroup_move_lists(struct page *page, bool active);
extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
struct list_head *dst,
@@ -53,7 +54,6 @@ extern struct mem_cgroup *mem_cgroup_fro
extern int
mem_cgroup_prepare_migration(struct page *page, struct page *newpage);
extern void mem_cgroup_end_migration(struct page *page);
-extern int mem_cgroup_getref(struct page *page);
/*
* For memory reclaim.
@@ -98,6 +98,10 @@ static inline void mem_cgroup_uncharge_p
{
}
+static inline void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+}
+
static inline void mem_cgroup_move_lists(struct page *page, bool active)
{
}
@@ -123,10 +127,6 @@ static inline void mem_cgroup_end_migrat
{
}
-static inline void mem_cgroup_getref(struct page *page)
-{
-}
-
static inline int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
{
return 0;
diff -puN mm/filemap.c~memcg-remove-refcnt-from-page_cgroup mm/filemap.c
--- a/mm/filemap.c~memcg-remove-refcnt-from-page_cgroup
+++ a/mm/filemap.c
@@ -115,7 +115,7 @@ void __remove_from_page_cache(struct pag
{
struct address_space *mapping = page->mapping;
- mem_cgroup_uncharge_page(page);
+ mem_cgroup_uncharge_cache_page(page);
radix_tree_delete(&mapping->page_tree, page->index);
page->mapping = NULL;
mapping->nrpages--;
@@ -473,12 +473,12 @@ int add_to_page_cache(struct page *page,
mapping->nrpages++;
__inc_zone_page_state(page, NR_FILE_PAGES);
} else
- mem_cgroup_uncharge_page(page);
+ mem_cgroup_uncharge_cache_page(page);
write_unlock_irq(&mapping->tree_lock);
radix_tree_preload_end();
} else
- mem_cgroup_uncharge_page(page);
+ mem_cgroup_uncharge_cache_page(page);
out:
return error;
}
diff -puN mm/memcontrol.c~memcg-remove-refcnt-from-page_cgroup mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-remove-refcnt-from-page_cgroup
+++ a/mm/memcontrol.c
@@ -166,7 +166,6 @@ struct page_cgroup {
struct list_head lru; /* per cgroup LRU list */
struct page *page;
struct mem_cgroup *mem_cgroup;
- int ref_cnt; /* cached, mapped, migrating */
int flags;
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
@@ -185,6 +184,7 @@ static enum zone_type page_cgroup_zid(st
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
+ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
};
/*
@@ -552,9 +552,7 @@ retry:
*/
if (pc) {
VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
-
- pc->ref_cnt++;
+ VM_BUG_ON(!pc->mem_cgroup);
unlock_page_cgroup(page);
goto done;
}
@@ -570,10 +568,7 @@ retry:
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
- if (!memcg) {
- if (!mm)
- mm = &init_mm;
-
+ if (likely(!memcg)) {
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
/*
@@ -609,7 +604,6 @@ retry:
}
}
- pc->ref_cnt = 1;
pc->mem_cgroup = mem;
pc->page = page;
/*
@@ -653,6 +647,17 @@ err:
int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
{
+ /*
+ * If already mapped, we don't have to account.
+ * If page cache, page->mapping has address_space.
+ * But page->mapping may have out-of-use anon_vma pointer,
+ * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+ * is NULL.
+ */
+ if (page_mapped(page) || (page->mapping && !PageAnon(page)))
+ return 0;
+ if (unlikely(!mm))
+ mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
}
@@ -660,32 +665,17 @@ int mem_cgroup_charge(struct page *page,
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
- if (!mm)
+ if (unlikely(!mm))
mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
}
-int mem_cgroup_getref(struct page *page)
-{
- struct page_cgroup *pc;
-
- if (mem_cgroup_subsys.disabled)
- return 0;
-
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- VM_BUG_ON(!pc);
- pc->ref_cnt++;
- unlock_page_cgroup(page);
- return 0;
-}
-
/*
- * Uncharging is always a welcome operation, we never complain, simply
- * uncharge.
+ * uncharge if !page_mapped(page)
*/
-void mem_cgroup_uncharge_page(struct page *page)
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
@@ -704,29 +694,41 @@ void mem_cgroup_uncharge_page(struct pag
goto unlock;
VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
- if (--(pc->ref_cnt) == 0) {
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+ && ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
+ || page_mapped(page)))
+ goto unlock;
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
+ mz = page_cgroup_zoneinfo(pc);
+ spin_lock_irqsave(&mz->lru_lock, flags);
+ __mem_cgroup_remove_list(mz, pc);
+ spin_unlock_irqrestore(&mz->lru_lock, flags);
- mem = pc->mem_cgroup;
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
- kmem_cache_free(page_cgroup_cache, pc);
- return;
- }
+ mem = pc->mem_cgroup;
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ css_put(&mem->css);
+ kmem_cache_free(page_cgroup_cache, pc);
+ return;
unlock:
unlock_page_cgroup(page);
}
+void mem_cgroup_uncharge_page(struct page *page)
+{
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+ VM_BUG_ON(page_mapped(page));
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
/*
* Before starting migration, account against new page.
*/
@@ -757,15 +759,17 @@ int mem_cgroup_prepare_migration(struct
return ret;
}
-/* remove redundant charge */
+/* remove redundant charge if migration failed*/
void mem_cgroup_end_migration(struct page *newpage)
{
- mem_cgroup_uncharge_page(newpage);
+ /* At success, page->mapping is not NULL */
+ if (newpage->mapping)
+ __mem_cgroup_uncharge_common(newpage,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
}
/*
* This routine traverse page_cgroup in given list and drop them all.
- * This routine ignores page_cgroup->ref_cnt.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
*/
#define FORCE_UNCHARGE_BATCH (128)
@@ -795,7 +799,8 @@ static void mem_cgroup_force_empty_list(
* if it's under page migration.
*/
if (PageLRU(page)) {
- mem_cgroup_uncharge_page(page);
+ __mem_cgroup_uncharge_common(page,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
put_page(page);
if (--count <= 0) {
count = FORCE_UNCHARGE_BATCH;
diff -puN mm/migrate.c~memcg-remove-refcnt-from-page_cgroup mm/migrate.c
--- a/mm/migrate.c~memcg-remove-refcnt-from-page_cgroup
+++ a/mm/migrate.c
@@ -359,8 +359,7 @@ static int migrate_page_move_mapping(str
write_unlock_irq(&mapping->tree_lock);
if (!PageSwapCache(newpage)) {
- mem_cgroup_uncharge_page(page);
- mem_cgroup_getref(newpage);
+ mem_cgroup_uncharge_cache_page(page);
}
return 0;
diff -puN mm/rmap.c~memcg-remove-refcnt-from-page_cgroup mm/rmap.c
--- a/mm/rmap.c~memcg-remove-refcnt-from-page_cgroup
+++ a/mm/rmap.c
@@ -576,14 +576,8 @@ void page_add_anon_rmap(struct page *pag
VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
if (atomic_inc_and_test(&page->_mapcount))
__page_set_anon_rmap(page, vma, address);
- else {
+ else
__page_check_anon_rmap(page, vma, address);
- /*
- * We unconditionally charged during prepare, we uncharge here
- * This takes care of balancing the reference counts
- */
- mem_cgroup_uncharge_page(page);
- }
}
/**
@@ -614,12 +608,6 @@ void page_add_file_rmap(struct page *pag
{
if (atomic_inc_and_test(&page->_mapcount))
__inc_zone_page_state(page, NR_FILE_MAPPED);
- else
- /*
- * We unconditionally charged during prepare, we uncharge here
- * This takes care of balancing the reference counts
- */
- mem_cgroup_uncharge_page(page);
}
#ifdef CONFIG_DEBUG_VM
diff -puN mm/shmem.c~memcg-remove-refcnt-from-page_cgroup mm/shmem.c
--- a/mm/shmem.c~memcg-remove-refcnt-from-page_cgroup
+++ a/mm/shmem.c
@@ -922,20 +922,29 @@ found:
error = 1;
if (!inode)
goto out;
- /* Precharge page while we can wait, compensate afterwards */
- error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
+ error = radix_tree_preload(GFP_KERNEL);
if (error)
goto out;
- error = radix_tree_preload(GFP_KERNEL);
+ /*
+ * Because we use GFP_NOWAIT in add_to_page_cache(), we can see -ENOMEM
+ * failure because of memory pressure in memory resource controller.
+ * Then, precharge page while we can wait, uncharge at failure will be
+ * automatically done in add_to_page_cache()
+ */
+ error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
if (error)
- goto uncharge;
+ goto preload_out;
+
error = 1;
spin_lock(&info->lock);
ptr = shmem_swp_entry(info, idx, NULL);
if (ptr && ptr->val == entry.val)
- error = add_to_page_cache(page, inode->i_mapping,
- idx, GFP_NOWAIT);
+ error = add_to_page_cache(page, inode->i_mapping, idx,
+ GFP_NOWAIT);
+ else /* we don't have to account this page. */
+ mem_cgroup_uncharge_cache_page(page);
+
if (error == -EEXIST) {
struct page *filepage = find_get_page(inode->i_mapping, idx);
error = 1;
@@ -960,9 +969,8 @@ found:
if (ptr)
shmem_swp_unmap(ptr);
spin_unlock(&info->lock);
+preload_out:
radix_tree_preload_end();
-uncharge:
- mem_cgroup_uncharge_page(page);
out:
unlock_page(page);
page_cache_release(page);
@@ -1319,7 +1327,7 @@ repeat:
page_cache_release(swappage);
goto failed;
}
- mem_cgroup_uncharge_page(swappage);
+ mem_cgroup_uncharge_cache_page(swappage);
}
page_cache_release(swappage);
goto repeat;
@@ -1358,6 +1366,8 @@ repeat:
}
if (!filepage) {
+ int ret;
+
spin_unlock(&info->lock);
filepage = shmem_alloc_page(gfp, info, idx);
if (!filepage) {
@@ -1386,10 +1396,17 @@ repeat:
swap = *entry;
shmem_swp_unmap(entry);
}
- if (error || swap.val || 0 != add_to_page_cache_lru(
- filepage, mapping, idx, GFP_NOWAIT)) {
+ if (error || swap.val)
+ mem_cgroup_uncharge_cache_page(filepage);
+ else
+ ret = add_to_page_cache_lru(filepage, mapping,
+ idx, GFP_NOWAIT);
+ /*
+ * At add_to_page_cache_lru() failure, uncharge will
+ * be done automatically.
+ */
+ if (error || swap.val || ret) {
spin_unlock(&info->lock);
- mem_cgroup_uncharge_page(filepage);
page_cache_release(filepage);
shmem_unacct_blocks(info->flags, 1);
shmem_free_blocks(inode, 1);
@@ -1398,7 +1415,6 @@ repeat:
goto failed;
goto repeat;
}
- mem_cgroup_uncharge_page(filepage);
info->flags |= SHMEM_PAGEIN;
}
_
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
origin.patch
memory-hotplug-memmap_init_zone-called-twice.patch
memory_hotplug-check-for-walk_memory_resource-failure-in-online_pages.patch
memory_hotplug-always-initialize-pageblock-bitmap.patch
mark-res_counter_charge_locked-with-__must_check.patch
memcg-make-global-var-read_mostly.patch
memcg-avoid-unnecessary-initialization.patch
memcg-better-migration-handling.patch
memcg-remove-refcnt-from-page_cgroup.patch
memcg-handle-swap-cache.patch
memcg-helper-function-for-relcaim-from-shmem.patch
memcg-add-hints-for-branch.patch
memcg-remove-a-redundant-check.patch
--
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