diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 108 | ||||
| -rw-r--r-- | mm/migrate.c | 42 |
2 files changed, 66 insertions, 84 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c34eb52bdc3..b71195e8198 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -627,34 +627,6 @@ int mem_cgroup_newpage_charge(struct page *page, MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL); } -/* - * same as mem_cgroup_newpage_charge(), now. - * But what we assume is different from newpage, and this is special case. - * treat this in special function. easy for maintenance. - */ - -int mem_cgroup_charge_migrate_fixup(struct page *page, - struct mm_struct *mm, gfp_t gfp_mask) -{ - if (mem_cgroup_subsys.disabled) - return 0; - - if (PageCompound(page)) - return 0; - - 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); -} - - - - int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { @@ -697,7 +669,6 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL); } - void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) { struct page_cgroup *pc; @@ -782,13 +753,13 @@ void mem_cgroup_uncharge_cache_page(struct page *page) } /* - * Before starting migration, account against new page. + * 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) +int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr) { struct page_cgroup *pc; struct mem_cgroup *mem = NULL; - enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; int ret = 0; if (mem_cgroup_subsys.disabled) @@ -799,42 +770,67 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; css_get(&mem->css); - if (PageCgroupCache(pc)) { - if (page_is_file_cache(page)) - ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; - else - ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; - } } unlock_page_cgroup(pc); + if (mem) { - ret = mem_cgroup_charge_common(newpage, NULL, - GFP_HIGHUSER_MOVABLE, - ctype, mem); + ret = mem_cgroup_try_charge(NULL, GFP_HIGHUSER_MOVABLE, &mem); css_put(&mem->css); } + *ptr = mem; return ret; } /* remove redundant charge if migration failed*/ -void mem_cgroup_end_migration(struct page *newpage) +void mem_cgroup_end_migration(struct mem_cgroup *mem, + struct page *oldpage, struct page *newpage) { + struct page *target, *unused; + struct page_cgroup *pc; + enum charge_type ctype; + + if (!mem) + return; + + /* at migration success, oldpage->mapping is NULL. */ + if (oldpage->mapping) { + target = oldpage; + unused = NULL; + } else { + target = newpage; + unused = oldpage; + } + + if (PageAnon(target)) + ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; + else if (page_is_file_cache(target)) + ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; + else + ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; + + /* unused page is not on radix-tree now. */ + if (unused && ctype != MEM_CGROUP_CHARGE_TYPE_MAPPED) + __mem_cgroup_uncharge_common(unused, ctype); + + pc = lookup_page_cgroup(target); /* - * At success, page->mapping is not NULL. - * special rollback care is necessary when - * 1. at migration failure. (newpage->mapping is cleared in this case) - * 2. the newpage was moved but not remapped again because the task - * exits and the newpage is obsolete. In this case, the new page - * may be a swapcache. So, we just call mem_cgroup_uncharge_page() - * always for avoiding mess. The page_cgroup will be removed if - * unnecessary. File cache pages is still on radix-tree. Don't - * care it. + * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup. + * So, double-counting is effectively avoided. + */ + __mem_cgroup_commit_charge(mem, pc, ctype); + + /* + * Both of oldpage and newpage are still under lock_page(). + * Then, we don't have to care about race in radix-tree. + * But we have to be careful that this page is unmapped or not. + * + * There is a case for !page_mapped(). At the start of + * migration, oldpage was mapped. But now, it's zapped. + * But we know *target* page is not freed/reused under us. + * mem_cgroup_uncharge_page() does all necessary checks. */ - if (!newpage->mapping) - __mem_cgroup_uncharge_common(newpage, - MEM_CGROUP_CHARGE_TYPE_FORCE); - else if (PageAnon(newpage)) - mem_cgroup_uncharge_page(newpage); + if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) + mem_cgroup_uncharge_page(target); } /* diff --git a/mm/migrate.c b/mm/migrate.c index 246dcb973ae..a30ea5fcf9f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -121,20 +121,6 @@ static void remove_migration_pte(struct vm_area_struct *vma, if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old) goto out; - /* - * Yes, ignore the return value from a GFP_ATOMIC mem_cgroup_charge. - * Failure is not an option here: we're now expected to remove every - * migration pte, and will cause crashes otherwise. Normally this - * is not an issue: mem_cgroup_prepare_migration bumped up the old - * page_cgroup count for safety, that's now attached to the new page, - * so this charge should just be another incrementation of the count, - * to keep in balance with rmap.c's mem_cgroup_uncharging. But if - * there's been a force_empty, those reference counts may no longer - * be reliable, and this charge can actually fail: oh well, we don't - * make the situation any worse by proceeding as if it had succeeded. - */ - mem_cgroup_charge_migrate_fixup(new, mm, GFP_ATOMIC); - get_page(new); pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); if (is_write_migration_entry(entry)) @@ -378,9 +364,6 @@ static void migrate_page_copy(struct page *newpage, struct page *page) anon = PageAnon(page); page->mapping = NULL; - if (!anon) /* This page was removed from radix-tree. */ - mem_cgroup_uncharge_cache_page(page); - /* * If any waiters have accumulated on the new page then * wake them up. @@ -614,6 +597,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, struct page *newpage = get_new_page(page, private, &result); int rcu_locked = 0; int charge = 0; + struct mem_cgroup *mem; if (!newpage) return -ENOMEM; @@ -623,24 +607,26 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, goto move_newpage; } - charge = mem_cgroup_prepare_migration(page, newpage); - if (charge == -ENOMEM) { - rc = -ENOMEM; - goto move_newpage; - } /* prepare cgroup just returns 0 or -ENOMEM */ - BUG_ON(charge); - rc = -EAGAIN; + if (!trylock_page(page)) { if (!force) goto move_newpage; lock_page(page); } + /* charge against new page */ + charge = mem_cgroup_prepare_migration(page, &mem); + if (charge == -ENOMEM) { + rc = -ENOMEM; + goto unlock; + } + BUG_ON(charge); + if (PageWriteback(page)) { if (!force) - goto unlock; + goto uncharge; wait_on_page_writeback(page); } /* @@ -693,7 +679,9 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, rcu_unlock: if (rcu_locked) rcu_read_unlock(); - +uncharge: + if (!charge) + mem_cgroup_end_migration(mem, page, newpage); unlock: unlock_page(page); @@ -709,8 +697,6 @@ unlock: } move_newpage: - if (!charge) - mem_cgroup_end_migration(newpage); /* * Move the new page to the LRU. If migration was not successful |