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author | 2009-01-07 18:08:35 -0800 | |
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committer | 2009-01-08 08:31:10 -0800 | |
commit | b5a84319a4343a0db753436fd8147e61eaafa7ea (patch) | |
tree | 5faae671b431b50a32a2d8c7a57cc9361d8f336d /mm | |
parent | memcg: fix LRU accounting for SwapCache (diff) | |
download | linux-b5a84319a4343a0db753436fd8147e61eaafa7ea.tar.gz linux-b5a84319a4343a0db753436fd8147e61eaafa7ea.tar.bz2 linux-b5a84319a4343a0db753436fd8147e61eaafa7ea.zip |
memcg: fix shmem's swap accounting
Now, you can see following even when swap accounting is enabled.
1. Create Group 01, and 02.
2. allocate a "file" on tmpfs by a task under 01.
3. swap out the "file" (by memory pressure)
4. Read "file" from a task in group 02.
5. the charge of "file" is moved to group 02.
This is not ideal behavior. This is because SwapCache which was loaded
by read-ahead is not taken into account..
This is a patch to fix shmem's swapcache behavior.
- remove mem_cgroup_cache_charge_swapin().
- Add SwapCache handler routine to mem_cgroup_cache_charge().
By this, shmem's file cache is charged at add_to_page_cache()
with GFP_NOWAIT.
- pass the page of swapcache to shrink_mem_cgroup.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memcontrol.c | 134 | ||||
-rw-r--r-- | mm/shmem.c | 30 |
2 files changed, 72 insertions, 92 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f50cb7b1efdb..93a792871804 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -893,6 +893,23 @@ nomem: return -ENOMEM; } +static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) +{ + struct mem_cgroup *mem; + swp_entry_t ent; + + if (!PageSwapCache(page)) + return NULL; + + ent.val = page_private(page); + mem = lookup_swap_cgroup(ent); + if (!mem) + return NULL; + if (!css_tryget(&mem->css)) + return NULL; + return mem; +} + /* * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be * USED state. If already USED, uncharge and return. @@ -1084,6 +1101,9 @@ int mem_cgroup_newpage_charge(struct page *page, int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { + struct mem_cgroup *mem = NULL; + int ret; + if (mem_cgroup_disabled()) return 0; if (PageCompound(page)) @@ -1096,6 +1116,8 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, * For GFP_NOWAIT case, the page may be pre-charged before calling * add_to_page_cache(). (See shmem.c) check it here and avoid to call * charge twice. (It works but has to pay a bit larger cost.) + * And when the page is SwapCache, it should take swap information + * into account. This is under lock_page() now. */ if (!(gfp_mask & __GFP_WAIT)) { struct page_cgroup *pc; @@ -1112,15 +1134,40 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, unlock_page_cgroup(pc); } - if (unlikely(!mm)) + if (do_swap_account && PageSwapCache(page)) { + mem = try_get_mem_cgroup_from_swapcache(page); + if (mem) + mm = NULL; + else + mem = NULL; + /* SwapCache may be still linked to LRU now. */ + mem_cgroup_lru_del_before_commit_swapcache(page); + } + + if (unlikely(!mm && !mem)) mm = &init_mm; if (page_is_file_cache(page)) return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_CACHE, NULL); - else - return mem_cgroup_charge_common(page, mm, gfp_mask, - MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL); + + ret = mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_SHMEM, mem); + if (mem) + css_put(&mem->css); + if (PageSwapCache(page)) + mem_cgroup_lru_add_after_commit_swapcache(page); + + if (do_swap_account && !ret && PageSwapCache(page)) { + swp_entry_t ent = {.val = page_private(page)}; + /* avoid double counting */ + mem = swap_cgroup_record(ent, NULL); + if (mem) { + res_counter_uncharge(&mem->memsw, PAGE_SIZE); + mem_cgroup_put(mem); + } + } + return ret; } /* @@ -1134,7 +1181,6 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, gfp_t mask, struct mem_cgroup **ptr) { struct mem_cgroup *mem; - swp_entry_t ent; int ret; if (mem_cgroup_disabled()) @@ -1142,7 +1188,6 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, if (!do_swap_account) goto charge_cur_mm; - /* * A racing thread's fault, or swapoff, may have already updated * the pte, and even removed page from swap cache: return success @@ -1150,14 +1195,9 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, */ if (!PageSwapCache(page)) return 0; - - ent.val = page_private(page); - - mem = lookup_swap_cgroup(ent); + mem = try_get_mem_cgroup_from_swapcache(page); if (!mem) goto charge_cur_mm; - if (!css_tryget(&mem->css)) - goto charge_cur_mm; *ptr = mem; ret = __mem_cgroup_try_charge(NULL, mask, ptr, true); /* drop extra refcnt from tryget */ @@ -1169,62 +1209,6 @@ charge_cur_mm: return __mem_cgroup_try_charge(mm, mask, ptr, true); } -#ifdef CONFIG_SWAP - -int mem_cgroup_cache_charge_swapin(struct page *page, - struct mm_struct *mm, gfp_t mask, bool locked) -{ - int ret = 0; - - if (mem_cgroup_disabled()) - return 0; - if (unlikely(!mm)) - mm = &init_mm; - if (!locked) - lock_page(page); - /* - * If not locked, the page can be dropped from SwapCache until - * we reach here. - */ - if (PageSwapCache(page)) { - struct mem_cgroup *mem = NULL; - swp_entry_t ent; - - ent.val = page_private(page); - if (do_swap_account) { - mem = lookup_swap_cgroup(ent); - if (mem) { - if (css_tryget(&mem->css)) - mm = NULL; /* charge to recorded */ - else - mem = NULL; /* charge to current */ - } - } - /* SwapCache may be still linked to LRU now. */ - mem_cgroup_lru_del_before_commit_swapcache(page); - ret = mem_cgroup_charge_common(page, mm, mask, - MEM_CGROUP_CHARGE_TYPE_SHMEM, mem); - mem_cgroup_lru_add_after_commit_swapcache(page); - /* drop extra refcnt from tryget */ - if (mem) - css_put(&mem->css); - - if (!ret && do_swap_account) { - /* avoid double counting */ - mem = swap_cgroup_record(ent, NULL); - if (mem) { - res_counter_uncharge(&mem->memsw, PAGE_SIZE); - mem_cgroup_put(mem); - } - } - } - if (!locked) - unlock_page(page); - - return ret; -} -#endif - void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) { struct page_cgroup *pc; @@ -1486,18 +1470,20 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem, * This is typically used for page reclaiming for shmem for reducing side * effect of page allocation from shmem, which is used by some mem_cgroup. */ -int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask) +int mem_cgroup_shrink_usage(struct page *page, + struct mm_struct *mm, + gfp_t gfp_mask) { - struct mem_cgroup *mem; + struct mem_cgroup *mem = NULL; int progress = 0; int retry = MEM_CGROUP_RECLAIM_RETRIES; if (mem_cgroup_disabled()) return 0; - if (!mm) - return 0; - - mem = try_get_mem_cgroup_from_mm(mm); + if (page) + mem = try_get_mem_cgroup_from_swapcache(page); + if (!mem && mm) + mem = try_get_mem_cgroup_from_mm(mm); if (unlikely(!mem)) return 0; diff --git a/mm/shmem.c b/mm/shmem.c index bbb7b043c986..5d0de96c9789 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -929,11 +929,11 @@ found: if (!inode) goto out; /* - * Charge page using GFP_HIGHUSER_MOVABLE while we can wait. - * charged back to the user(not to caller) when swap account is used. + * Charge page using GFP_KERNEL while we can wait. + * Charged back to the user(not to caller) when swap account is used. + * add_to_page_cache() will be called with GFP_NOWAIT. */ - error = mem_cgroup_cache_charge_swapin(page, current->mm, GFP_KERNEL, - true); + error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); if (error) goto out; error = radix_tree_preload(GFP_KERNEL); @@ -1270,16 +1270,6 @@ repeat: goto repeat; } wait_on_page_locked(swappage); - /* - * We want to avoid charge at add_to_page_cache(). - * charge against this swap cache here. - */ - if (mem_cgroup_cache_charge_swapin(swappage, - current->mm, gfp & GFP_RECLAIM_MASK, false)) { - page_cache_release(swappage); - error = -ENOMEM; - goto failed; - } page_cache_release(swappage); goto repeat; } @@ -1334,15 +1324,19 @@ repeat: } else { shmem_swp_unmap(entry); spin_unlock(&info->lock); - unlock_page(swappage); - page_cache_release(swappage); if (error == -ENOMEM) { /* allow reclaim from this memory cgroup */ - error = mem_cgroup_shrink_usage(current->mm, + error = mem_cgroup_shrink_usage(swappage, + current->mm, gfp); - if (error) + if (error) { + unlock_page(swappage); + page_cache_release(swappage); goto failed; + } } + unlock_page(swappage); + page_cache_release(swappage); goto repeat; } } else if (sgp == SGP_READ && !filepage) { |