diff options
| -rw-r--r-- | include/linux/memcontrol.h | 110 | ||||
| -rw-r--r-- | mm/memcontrol.c | 170 |
2 files changed, 280 insertions, 0 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e98a74c..afa2ad4 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -21,6 +21,7 @@ #define _LINUX_MEMCONTROL_H #include <linux/cgroup.h> #include <linux/vm_event_item.h> +#include <linux/hardirq.h> struct mem_cgroup; struct page_cgroup; @@ -414,5 +415,114 @@ static inline void sock_release_memcg(struct sock *sk) { } #endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */ + +#ifdef CONFIG_MEMCG_KMEM +static inline bool memcg_kmem_enabled(void) +{ + return true; +} + +/* + * In general, we'll do everything in our power to not incur in any overhead + * for non-memcg users for the kmem functions. Not even a function call, if we + * can avoid it. + * + * Therefore, we'll inline all those functions so that in the best case, we'll + * see that kmemcg is off for everybody and proceed quickly. If it is on, + * we'll still do most of the flag checking inline. We check a lot of + * conditions, but because they are pretty simple, they are expected to be + * fast. + */ +bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, + int order); +void __memcg_kmem_commit_charge(struct page *page, + struct mem_cgroup *memcg, int order); +void __memcg_kmem_uncharge_pages(struct page *page, int order); + +/** + * memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed. + * @gfp: the gfp allocation flags. + * @memcg: a pointer to the memcg this was charged against. + * @order: allocation order. + * + * returns true if the memcg where the current task belongs can hold this + * allocation. + * + * We return true automatically if this allocation is not to be accounted to + * any memcg. + */ +static inline bool +memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order) +{ + if (!memcg_kmem_enabled()) + return true; + + /* + * __GFP_NOFAIL allocations will move on even if charging is not + * possible. Therefore we don't even try, and have this allocation + * unaccounted. We could in theory charge it with + * res_counter_charge_nofail, but we hope those allocations are rare, + * and won't be worth the trouble. + */ + if (!(gfp & __GFP_KMEMCG) || (gfp & __GFP_NOFAIL)) + return true; + if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD)) + return true; + + /* If the test is dying, just let it go. */ + if (unlikely(fatal_signal_pending(current))) + return true; + + return __memcg_kmem_newpage_charge(gfp, memcg, order); +} + +/** + * memcg_kmem_uncharge_pages: uncharge pages from memcg + * @page: pointer to struct page being freed + * @order: allocation order. + * + * there is no need to specify memcg here, since it is embedded in page_cgroup + */ +static inline void +memcg_kmem_uncharge_pages(struct page *page, int order) +{ + if (memcg_kmem_enabled()) + __memcg_kmem_uncharge_pages(page, order); +} + +/** + * memcg_kmem_commit_charge: embeds correct memcg in a page + * @page: pointer to struct page recently allocated + * @memcg: the memcg structure we charged against + * @order: allocation order. + * + * Needs to be called after memcg_kmem_newpage_charge, regardless of success or + * failure of the allocation. if @page is NULL, this function will revert the + * charges. Otherwise, it will commit the memcg given by @memcg to the + * corresponding page_cgroup. + */ +static inline void +memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order) +{ + if (memcg_kmem_enabled() && memcg) + __memcg_kmem_commit_charge(page, memcg, order); +} + +#else +static inline bool +memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order) +{ + return true; +} + +static inline void memcg_kmem_uncharge_pages(struct page *page, int order) +{ +} + +static inline void +memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order) +{ +} +#endif /* CONFIG_MEMCG_KMEM */ #endif /* _LINUX_MEMCONTROL_H */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index bba1cb4..b9afa06 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -10,6 +10,10 @@ * Copyright (C) 2009 Nokia Corporation * Author: Kirill A. Shutemov * + * Kernel Memory Controller + * Copyright (C) 2012 Parallels Inc. and Google Inc. + * Authors: Glauber Costa and Suleiman Souhlal + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or @@ -2661,6 +2665,172 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, memcg_check_events(memcg, page); } +#ifdef CONFIG_MEMCG_KMEM +static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) +{ + return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) && + (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK); +} + +static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) +{ + struct res_counter *fail_res; + struct mem_cgroup *_memcg; + int ret = 0; + bool may_oom; + + ret = res_counter_charge(&memcg->kmem, size, &fail_res); + if (ret) + return ret; + + /* + * Conditions under which we can wait for the oom_killer. Those are + * the same conditions tested by the core page allocator + */ + may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY); + + _memcg = memcg; + ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT, + &_memcg, may_oom); + + if (ret == -EINTR) { + /* + * __mem_cgroup_try_charge() chosed to bypass to root due to + * OOM kill or fatal signal. Since our only options are to + * either fail the allocation or charge it to this cgroup, do + * it as a temporary condition. But we can't fail. From a + * kmem/slab perspective, the cache has already been selected, + * by mem_cgroup_kmem_get_cache(), so it is too late to change + * our minds. + * + * This condition will only trigger if the task entered + * memcg_charge_kmem in a sane state, but was OOM-killed during + * __mem_cgroup_try_charge() above. Tasks that were already + * dying when the allocation triggers should have been already + * directed to the root cgroup in memcontrol.h + */ + res_counter_charge_nofail(&memcg->res, size, &fail_res); + if (do_swap_account) + res_counter_charge_nofail(&memcg->memsw, size, + &fail_res); + ret = 0; + } else if (ret) + res_counter_uncharge(&memcg->kmem, size); + + return ret; +} + +static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size) +{ + res_counter_uncharge(&memcg->kmem, size); + res_counter_uncharge(&memcg->res, size); + if (do_swap_account) + res_counter_uncharge(&memcg->memsw, size); +} + +/* + * We need to verify if the allocation against current->mm->owner's memcg is + * possible for the given order. But the page is not allocated yet, so we'll + * need a further commit step to do the final arrangements. + * + * It is possible for the task to switch cgroups in this mean time, so at + * commit time, we can't rely on task conversion any longer. We'll then use + * the handle argument to return to the caller which cgroup we should commit + * against. We could also return the memcg directly and avoid the pointer + * passing, but a boolean return value gives better semantics considering + * the compiled-out case as well. + * + * Returning true means the allocation is possible. + */ +bool +__memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) +{ + struct mem_cgroup *memcg; + int ret; + + *_memcg = NULL; + memcg = try_get_mem_cgroup_from_mm(current->mm); + + /* + * very rare case described in mem_cgroup_from_task. Unfortunately there + * isn't much we can do without complicating this too much, and it would + * be gfp-dependent anyway. Just let it go + */ + if (unlikely(!memcg)) + return true; + + if (!memcg_can_account_kmem(memcg)) { + css_put(&memcg->css); + return true; + } + + mem_cgroup_get(memcg); + + ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order); + if (!ret) + *_memcg = memcg; + else + mem_cgroup_put(memcg); + + css_put(&memcg->css); + return (ret == 0); +} + +void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, + int order) +{ + struct page_cgroup *pc; + + VM_BUG_ON(mem_cgroup_is_root(memcg)); + + /* The page allocation failed. Revert */ + if (!page) { + memcg_uncharge_kmem(memcg, PAGE_SIZE << order); + mem_cgroup_put(memcg); + return; + } + + pc = lookup_page_cgroup(page); + lock_page_cgroup(pc); + pc->mem_cgroup = memcg; + SetPageCgroupUsed(pc); + unlock_page_cgroup(pc); +} + +void __memcg_kmem_uncharge_pages(struct page *page, int order) +{ + struct mem_cgroup *memcg = NULL; + struct page_cgroup *pc; + + + pc = lookup_page_cgroup(page); + /* + * Fast unlocked return. Theoretically might have changed, have to + * check again after locking. + */ + if (!PageCgroupUsed(pc)) + return; + + lock_page_cgroup(pc); + if (PageCgroupUsed(pc)) { + memcg = pc->mem_cgroup; + ClearPageCgroupUsed(pc); + } + unlock_page_cgroup(pc); + + /* + * We trust that only if there is a memcg associated with the page, it + * is a valid allocation + */ + if (!memcg) + return; + + VM_BUG_ON(mem_cgroup_is_root(memcg)); + memcg_uncharge_kmem(memcg, PAGE_SIZE << order); + mem_cgroup_put(memcg); +} +#endif /* CONFIG_MEMCG_KMEM */ + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION) |
