diff options
| -rw-r--r-- | include/linux/memcontrol.h | 11 | ||||
| -rw-r--r-- | mm/memcontrol.c | 67 | ||||
| -rw-r--r-- | mm/migrate.c | 11 |
3 files changed, 43 insertions, 46 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5a3ee64..8d9489f 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -98,9 +98,9 @@ int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup) extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg); -extern int -mem_cgroup_prepare_migration(struct page *page, - struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask); +extern void +mem_cgroup_prepare_migration(struct page *page, struct page *newpage, + struct mem_cgroup **memcgp); extern void mem_cgroup_end_migration(struct mem_cgroup *memcg, struct page *oldpage, struct page *newpage, bool migration_ok); @@ -276,11 +276,10 @@ static inline struct cgroup_subsys_state return NULL; } -static inline int +static inline void mem_cgroup_prepare_migration(struct page *page, struct page *newpage, - struct mem_cgroup **memcgp, gfp_t gfp_mask) + struct mem_cgroup **memcgp) { - return 0; } static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0f692a2d..7eadcda 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2976,7 +2976,8 @@ direct_uncharge: * uncharge if !page_mapped(page) */ static struct mem_cgroup * -__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) +__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype, + bool end_migration) { struct mem_cgroup *memcg = NULL; unsigned int nr_pages = 1; @@ -3020,7 +3021,16 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) /* fallthrough */ case MEM_CGROUP_CHARGE_TYPE_DROP: /* See mem_cgroup_prepare_migration() */ - if (page_mapped(page) || PageCgroupMigration(pc)) + if (page_mapped(page)) + goto unlock_out; + /* + * Pages under migration may not be uncharged. But + * end_migration() /must/ be the one uncharging the + * unused post-migration page and so it has to call + * here with the migration bit still set. See the + * res_counter handling below. + */ + if (!end_migration && PageCgroupMigration(pc)) goto unlock_out; break; case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: @@ -3054,7 +3064,12 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) mem_cgroup_swap_statistics(memcg, true); mem_cgroup_get(memcg); } - if (!mem_cgroup_is_root(memcg)) + /* + * Migration does not charge the res_counter for the + * replacement page, so leave it alone when phasing out the + * page that is unused after the migration. + */ + if (!end_migration && !mem_cgroup_is_root(memcg)) mem_cgroup_do_uncharge(memcg, nr_pages, ctype); return memcg; @@ -3070,14 +3085,14 @@ void mem_cgroup_uncharge_page(struct page *page) if (page_mapped(page)) return; VM_BUG_ON(page->mapping && !PageAnon(page)); - __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON); + __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false); } void mem_cgroup_uncharge_cache_page(struct page *page) { VM_BUG_ON(page_mapped(page)); VM_BUG_ON(page->mapping); - __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); + __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false); } /* @@ -3141,7 +3156,7 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) if (!swapout) /* this was a swap cache but the swap is unused ! */ ctype = MEM_CGROUP_CHARGE_TYPE_DROP; - memcg = __mem_cgroup_uncharge_common(page, ctype); + memcg = __mem_cgroup_uncharge_common(page, ctype, false); /* * record memcg information, if swapout && memcg != NULL, @@ -3231,19 +3246,18 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry, * Before starting migration, account PAGE_SIZE to mem_cgroup that the old * page belongs to. */ -int mem_cgroup_prepare_migration(struct page *page, - struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask) +void mem_cgroup_prepare_migration(struct page *page, struct page *newpage, + struct mem_cgroup **memcgp) { struct mem_cgroup *memcg = NULL; struct page_cgroup *pc; enum charge_type ctype; - int ret = 0; *memcgp = NULL; VM_BUG_ON(PageTransHuge(page)); if (mem_cgroup_disabled()) - return 0; + return; pc = lookup_page_cgroup(page); lock_page_cgroup(pc); @@ -3288,24 +3302,9 @@ int mem_cgroup_prepare_migration(struct page *page, * we return here. */ if (!memcg) - return 0; + return; *memcgp = memcg; - ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false); - css_put(&memcg->css);/* drop extra refcnt */ - if (ret) { - if (PageAnon(page)) { - lock_page_cgroup(pc); - ClearPageCgroupMigration(pc); - unlock_page_cgroup(pc); - /* - * The old page may be fully unmapped while we kept it. - */ - mem_cgroup_uncharge_page(page); - } - /* we'll need to revisit this error code (we have -EINTR) */ - return -ENOMEM; - } /* * We charge new page before it's used/mapped. So, even if unlock_page() * is called before end_migration, we can catch all events on this new @@ -3318,8 +3317,12 @@ int mem_cgroup_prepare_migration(struct page *page, ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; else ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; + /* + * The page is committed to the memcg, but it's not actually + * charged to the res_counter since we plan on replacing the + * old one and only one page is going to be left afterwards. + */ __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false); - return ret; } /* remove redundant charge if migration failed*/ @@ -3341,6 +3344,12 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg, used = newpage; unused = oldpage; } + anon = PageAnon(used); + __mem_cgroup_uncharge_common(unused, + anon ? MEM_CGROUP_CHARGE_TYPE_ANON + : MEM_CGROUP_CHARGE_TYPE_CACHE, + true); + css_put(&memcg->css); /* * We disallowed uncharge of pages under migration because mapcount * of the page goes down to zero, temporarly. @@ -3350,10 +3359,6 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg, lock_page_cgroup(pc); ClearPageCgroupMigration(pc); unlock_page_cgroup(pc); - anon = PageAnon(used); - __mem_cgroup_uncharge_common(unused, - anon ? MEM_CGROUP_CHARGE_TYPE_ANON - : MEM_CGROUP_CHARGE_TYPE_CACHE); /* * If a page is a file cache, radix-tree replacement is very atomic diff --git a/mm/migrate.c b/mm/migrate.c index 6c37c51..77ed2d7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -683,7 +683,6 @@ static int __unmap_and_move(struct page *page, struct page *newpage, { int rc = -EAGAIN; int remap_swapcache = 1; - int charge = 0; struct mem_cgroup *mem; struct anon_vma *anon_vma = NULL; @@ -725,12 +724,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } /* charge against new page */ - charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL); - if (charge == -ENOMEM) { - rc = -ENOMEM; - goto unlock; - } - BUG_ON(charge); + mem_cgroup_prepare_migration(page, newpage, &mem); if (PageWriteback(page)) { /* @@ -820,8 +814,7 @@ skip_unmap: put_anon_vma(anon_vma); uncharge: - if (!charge) - mem_cgroup_end_migration(mem, page, newpage, rc == 0); + mem_cgroup_end_migration(mem, page, newpage, rc == 0); unlock: unlock_page(page); out: |