From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 17 Sep 2008 15:51:12 -0700 From: Andrew Morton Subject: Re: [PATCH -mm] memcg: fix handling of shmem migration(v2) Message-Id: <20080917155112.eefd2f8a.akpm@linux-foundation.org> In-Reply-To: <20080917165544.3873bbb2.nishimura@mxp.nes.nec.co.jp> References: <20080917133149.b012a1c2.nishimura@mxp.nes.nec.co.jp> <20080917144659.2e363edc.kamezawa.hiroyu@jp.fujitsu.com> <20080917145003.fb4d0b95.kamezawa.hiroyu@jp.fujitsu.com> <20080917151951.9a181e7d.nishimura@mxp.nes.nec.co.jp> <20080917153826.8efbdc4b.kamezawa.hiroyu@jp.fujitsu.com> <20080917154511.683691d1.nishimura@mxp.nes.nec.co.jp> <20080917165544.3873bbb2.nishimura@mxp.nes.nec.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Daisuke Nishimura Cc: kamezawa.hiroyu@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, balbir@linux.vnet.ibm.com, xemul@openvz.org List-ID: On Wed, 17 Sep 2008 16:55:44 +0900 Daisuke Nishimura wrote: > Before this patch, if migrating shmem/tmpfs pages, newpage would be > charged with PAGE_CGROUP_FLAG_FILE set, while oldpage has been charged > without the flag. > > The problem here is mem_cgroup_move_lists doesn't clear(or set) > the PAGE_CGROUP_FLAG_FILE flag, so pc->flags of the newpage > remains PAGE_CGROUP_FLAG_FILE set even when the pc is moved to > another lru(anon) by mem_cgroup_move_lists. And this leads to > incorrect MEM_CGROUP_ZSTAT. > (In my test, I see an underflow of MEM_CGROUP_ZSTAT(active_file). > As a result, mem_cgroup_calc_reclaim returns very huge number and > causes soft lockup on page reclaim.) > > I'm not sure if mem_cgroup_move_lists should handle PAGE_CGROUP_FLAG_FILE > or not(I suppose it should be used to move between active <-> inactive, > not anon <-> file), I added MEM_CGROUP_CHARGE_TYPE_SHMEM for precharge > at shmem's page migration. > > > ChangeLog: v1->v2 > - instead of modifying migrate.c, modify memcontrol.c only. > - add MEM_CGROUP_CHARGE_TYPE_SHMEM. > > > Signed-off-by: Daisuke Nishimura > --- > mm/memcontrol.c | 13 ++++++++++--- > 1 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 2979d22..ef8812d 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -179,6 +179,7 @@ enum charge_type { > MEM_CGROUP_CHARGE_TYPE_CACHE = 0, > MEM_CGROUP_CHARGE_TYPE_MAPPED, > MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ > + MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ > }; > > /* > @@ -579,8 +580,10 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, > pc->flags |= PAGE_CGROUP_FLAG_FILE; > else > pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; > - } else > + } else if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) > pc->flags = PAGE_CGROUP_FLAG_ACTIVE; > + else /* MEM_CGROUP_CHARGE_TYPE_SHMEM */ > + pc->flags = PAGE_CGROUP_FLAG_CACHE | PAGE_CGROUP_FLAG_ACTIVE; > > lock_page_cgroup(page); > if (unlikely(page_get_page_cgroup(page))) { > @@ -739,8 +742,12 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) > if (pc) { > mem = pc->mem_cgroup; > css_get(&mem->css); > - if (pc->flags & PAGE_CGROUP_FLAG_CACHE) > - ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; > + if (pc->flags & PAGE_CGROUP_FLAG_CACHE) { > + if (page_is_file_cache(page)) > + ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; > + else > + ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; > + } > } > unlock_page_cgroup(page); > if (mem) { I queued this as a fix against vmscan-split-lru-lists-into-anon-file-sets.patch. Was that appropriate? If the bug you're fixing here is also present in mainline then I'll need to ask for a tested patch against mainline, please. -- 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/ . Don't email: email@kvack.org