From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>, "cgroups@vger.kernel.org" <cgroups@vger.kernel.org>, Michal Hocko <mhocko@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>, Glauber Costa <glommer@parallels.com>, Hugh Dickins <hughd@google.com>, Andrew Morton <akpm@linux-foundation.org> Subject: [PATCH 3/7] memcg: move charges to root at rmdir() Date: Thu, 12 Apr 2012 20:22:42 +0900 [thread overview] Message-ID: <4F86BB02.2060607@jp.fujitsu.com> (raw) In-Reply-To: <4F86B9BE.8000105@jp.fujitsu.com> As recently discussed, Tejun Heo, the cgroup maintainer, tries to remove ->pre_destroy() and cgroup will never return -EBUSY at rmdir(). To do that, in memcg, handling case of use_hierarchy==false is a problem. We move memcg's charges to its parent at rmdir(). If use_hierarchy==true, it's already accounted in the parent, no problem. If use_hierarchy==false, we cannot guarantee we can move all charges to the parent. This patch changes the behavior to move all charges to root_mem_cgroup if use_hierarchy=false. It seems this matches semantics of use_hierarchy==false,which means parent and child has no hierarchical relationship. With this, we can remove -ENOMEM error check at pre_destroy(), called at rmdir. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- Documentation/cgroups/memory.txt | 6 ++++-- mm/memcontrol.c | 38 ++++++++++++-------------------------- 2 files changed, 16 insertions(+), 28 deletions(-) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 84d4f00..f717f6a 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -377,8 +377,10 @@ cgroup might have some charge associated with it, even though all tasks have migrated away from it. (because we charge against pages, not against tasks.) -Such charges are freed or moved to their parent. At moving, both of RSS -and CACHES are moved to parent. +Such charges are freed or moved to their parent if use_hierarchy==true. +If use_hierarchy==false, charges are moved to root memory cgroup. + +At moving, both of RSS and CACHES are moved to parent. rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also. Charges recorded in swap information is not updated at removal of cgroup. diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3215880..8246418 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2662,15 +2662,14 @@ static int mem_cgroup_move_parent(struct page *page, struct mem_cgroup *child, gfp_t gfp_mask) { - struct cgroup *cg = child->css.cgroup; - struct cgroup *pcg = cg->parent; struct mem_cgroup *parent; unsigned int nr_pages; unsigned long uninitialized_var(flags); + bool need_cancel = false; int ret; /* Is ROOT ? */ - if (!pcg) + if (mem_cgroup_is_root(child)) return -EINVAL; ret = -EBUSY; @@ -2680,33 +2679,23 @@ static int mem_cgroup_move_parent(struct page *page, goto put; nr_pages = hpage_nr_pages(page); - parent = mem_cgroup_from_cont(pcg); - - if (!parent->use_hierarchy) { - ret = __mem_cgroup_try_charge(NULL, gfp_mask, - nr_pages, &parent, false); - if (ret) - goto put_back; + parent = parent_mem_cgroup(child); + if (!parent) { + parent = root_mem_cgroup; + need_cancel = true; } if (nr_pages > 1) flags = compound_lock_irqsave(page); - if (!parent->use_hierarchy) { - ret = mem_cgroup_move_account(page, nr_pages, pc, - child, parent, true); - if (ret) - __mem_cgroup_cancel_charge(parent, nr_pages); - } else { - ret = mem_cgroup_move_account(page, nr_pages, pc, - child, parent, false); - if (!ret) - __mem_cgroup_move_charge_parent(child, nr_pages); - } + ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, + need_cancel); + if (!need_cancel && !ret) + __mem_cgroup_move_charge_parent(child, nr_pages); if (nr_pages > 1) compound_unlock_irqrestore(page, flags); -put_back: + putback_lru_page(page); put: put_page(page); @@ -3677,7 +3666,7 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg, pc = lookup_page_cgroup(page); ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL); - if (ret == -ENOMEM || ret == -EINTR) + if (ret == -EINTR) break; if (ret == -EBUSY || ret == -EINVAL) { @@ -3738,9 +3727,6 @@ move_account: } mem_cgroup_end_move(memcg); memcg_oom_recover(memcg); - /* it seems parent cgroup doesn't have enough mem */ - if (ret == -ENOMEM) - goto try_to_free; cond_resched(); /* "ret" should also be checked to ensure all lists are empty. */ } while (memcg->res.usage > 0 || ret); -- 1.7.4.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org> To: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org> Cc: "linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org" <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>, "cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>, Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Subject: [PATCH 3/7] memcg: move charges to root at rmdir() Date: Thu, 12 Apr 2012 20:22:42 +0900 [thread overview] Message-ID: <4F86BB02.2060607@jp.fujitsu.com> (raw) In-Reply-To: <4F86B9BE.8000105-+CUm20s59erQFUHtdCDX3A@public.gmane.org> As recently discussed, Tejun Heo, the cgroup maintainer, tries to remove ->pre_destroy() and cgroup will never return -EBUSY at rmdir(). To do that, in memcg, handling case of use_hierarchy==false is a problem. We move memcg's charges to its parent at rmdir(). If use_hierarchy==true, it's already accounted in the parent, no problem. If use_hierarchy==false, we cannot guarantee we can move all charges to the parent. This patch changes the behavior to move all charges to root_mem_cgroup if use_hierarchy=false. It seems this matches semantics of use_hierarchy==false,which means parent and child has no hierarchical relationship. With this, we can remove -ENOMEM error check at pre_destroy(), called at rmdir. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org> --- Documentation/cgroups/memory.txt | 6 ++++-- mm/memcontrol.c | 38 ++++++++++++-------------------------- 2 files changed, 16 insertions(+), 28 deletions(-) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 84d4f00..f717f6a 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -377,8 +377,10 @@ cgroup might have some charge associated with it, even though all tasks have migrated away from it. (because we charge against pages, not against tasks.) -Such charges are freed or moved to their parent. At moving, both of RSS -and CACHES are moved to parent. +Such charges are freed or moved to their parent if use_hierarchy==true. +If use_hierarchy==false, charges are moved to root memory cgroup. + +At moving, both of RSS and CACHES are moved to parent. rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also. Charges recorded in swap information is not updated at removal of cgroup. diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3215880..8246418 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2662,15 +2662,14 @@ static int mem_cgroup_move_parent(struct page *page, struct mem_cgroup *child, gfp_t gfp_mask) { - struct cgroup *cg = child->css.cgroup; - struct cgroup *pcg = cg->parent; struct mem_cgroup *parent; unsigned int nr_pages; unsigned long uninitialized_var(flags); + bool need_cancel = false; int ret; /* Is ROOT ? */ - if (!pcg) + if (mem_cgroup_is_root(child)) return -EINVAL; ret = -EBUSY; @@ -2680,33 +2679,23 @@ static int mem_cgroup_move_parent(struct page *page, goto put; nr_pages = hpage_nr_pages(page); - parent = mem_cgroup_from_cont(pcg); - - if (!parent->use_hierarchy) { - ret = __mem_cgroup_try_charge(NULL, gfp_mask, - nr_pages, &parent, false); - if (ret) - goto put_back; + parent = parent_mem_cgroup(child); + if (!parent) { + parent = root_mem_cgroup; + need_cancel = true; } if (nr_pages > 1) flags = compound_lock_irqsave(page); - if (!parent->use_hierarchy) { - ret = mem_cgroup_move_account(page, nr_pages, pc, - child, parent, true); - if (ret) - __mem_cgroup_cancel_charge(parent, nr_pages); - } else { - ret = mem_cgroup_move_account(page, nr_pages, pc, - child, parent, false); - if (!ret) - __mem_cgroup_move_charge_parent(child, nr_pages); - } + ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, + need_cancel); + if (!need_cancel && !ret) + __mem_cgroup_move_charge_parent(child, nr_pages); if (nr_pages > 1) compound_unlock_irqrestore(page, flags); -put_back: + putback_lru_page(page); put: put_page(page); @@ -3677,7 +3666,7 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg, pc = lookup_page_cgroup(page); ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL); - if (ret == -ENOMEM || ret == -EINTR) + if (ret == -EINTR) break; if (ret == -EBUSY || ret == -EINVAL) { @@ -3738,9 +3727,6 @@ move_account: } mem_cgroup_end_move(memcg); memcg_oom_recover(memcg); - /* it seems parent cgroup doesn't have enough mem */ - if (ret == -ENOMEM) - goto try_to_free; cond_resched(); /* "ret" should also be checked to ensure all lists are empty. */ } while (memcg->res.usage > 0 || ret); -- 1.7.4.1
next prev parent reply other threads:[~2012-04-12 11:24 UTC|newest] Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-04-12 11:17 [PATCH v1 0/7] memcg remove pre_destroy KAMEZAWA Hiroyuki 2012-04-12 11:20 ` [PATCH 1/7] res_counter: add a function res_counter_move_parent() KAMEZAWA Hiroyuki 2012-04-12 11:20 ` KAMEZAWA Hiroyuki 2012-04-12 13:22 ` Glauber Costa 2012-04-12 14:30 ` Frederic Weisbecker 2012-04-13 0:57 ` KAMEZAWA Hiroyuki 2012-04-13 0:57 ` KAMEZAWA Hiroyuki 2012-04-13 1:04 ` Frederic Weisbecker 2012-04-13 1:04 ` Frederic Weisbecker 2012-04-13 1:05 ` KAMEZAWA Hiroyuki 2012-04-16 22:19 ` Tejun Heo 2012-04-16 22:19 ` Tejun Heo 2012-04-18 6:59 ` KAMEZAWA Hiroyuki 2012-04-18 6:59 ` KAMEZAWA Hiroyuki 2012-04-16 22:31 ` Tejun Heo 2012-04-18 7:04 ` KAMEZAWA Hiroyuki 2012-04-18 7:04 ` KAMEZAWA Hiroyuki 2012-04-18 17:03 ` Tejun Heo 2012-04-18 17:03 ` Tejun Heo 2012-04-12 11:21 ` [PATCH 2/7] memcg: move charge to parent only when necessary KAMEZAWA Hiroyuki 2012-04-12 11:21 ` KAMEZAWA Hiroyuki 2012-04-16 22:21 ` Tejun Heo 2012-04-16 22:21 ` Tejun Heo 2012-04-18 7:01 ` KAMEZAWA Hiroyuki 2012-04-18 7:01 ` KAMEZAWA Hiroyuki 2012-04-12 11:22 ` KAMEZAWA Hiroyuki [this message] 2012-04-12 11:22 ` [PATCH 3/7] memcg: move charges to root at rmdir() KAMEZAWA Hiroyuki 2012-04-16 22:30 ` Tejun Heo 2012-04-16 22:30 ` Tejun Heo 2012-04-18 7:02 ` KAMEZAWA Hiroyuki 2012-04-12 11:24 ` [PATCH 4/7] memcg: remove 'uncharge' argument from mem_cgroup_move_account() KAMEZAWA Hiroyuki 2012-04-12 11:24 ` KAMEZAWA Hiroyuki 2012-04-12 13:27 ` Glauber Costa 2012-04-13 1:01 ` KAMEZAWA Hiroyuki 2012-04-12 11:28 ` [PATCH 5/7] memcg: divide force_empty into 2 functions, avoid memory reclaim at rmdir KAMEZAWA Hiroyuki 2012-04-12 11:28 ` KAMEZAWA Hiroyuki 2012-04-12 13:33 ` Glauber Costa 2012-04-17 17:29 ` Ying Han 2012-04-18 7:14 ` KAMEZAWA Hiroyuki 2012-04-18 7:14 ` KAMEZAWA Hiroyuki 2012-04-12 11:30 ` [PATCH 6/7] memcg: remove pre_destroy() KAMEZAWA Hiroyuki 2012-04-12 11:30 ` KAMEZAWA Hiroyuki 2012-04-16 22:38 ` Tejun Heo 2012-04-18 7:12 ` KAMEZAWA Hiroyuki 2012-04-18 7:12 ` KAMEZAWA Hiroyuki 2012-04-17 17:47 ` Ying Han 2012-04-17 17:47 ` Ying Han 2012-04-12 11:31 ` [PATCH 7/7] memcg: remove drain_all_stock_sync KAMEZAWA Hiroyuki 2012-04-12 11:31 ` KAMEZAWA Hiroyuki 2012-04-12 13:35 ` Glauber Costa 2012-04-12 13:35 ` Glauber Costa 2012-04-12 13:20 ` [PATCH v1 0/7] memcg remove pre_destroy Glauber Costa 2012-04-12 13:20 ` Glauber Costa 2012-04-12 16:06 ` Tejun Heo 2012-04-12 16:06 ` Tejun Heo 2012-04-12 18:57 ` Aneesh Kumar K.V 2012-04-12 18:57 ` Aneesh Kumar K.V 2012-04-12 23:59 ` KAMEZAWA Hiroyuki 2012-04-13 8:50 ` Michal Hocko 2012-04-13 8:50 ` Michal Hocko 2012-04-13 22:19 ` Aneesh Kumar K.V 2012-04-13 22:19 ` Aneesh Kumar K.V 2012-04-16 22:41 ` Tejun Heo 2012-04-16 22:41 ` Tejun Heo 2012-04-17 17:35 ` Ying Han 2012-04-18 7:15 ` KAMEZAWA Hiroyuki 2012-04-18 7:15 ` KAMEZAWA Hiroyuki
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