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Date: Sun, 4 Mar 2012 09:29:52 +0800 From: Fengguang Wu <fengguang.wu@...el.com> To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> Cc: Andrew Morton <akpm@...ux-foundation.org>, Greg Thelen <gthelen@...gle.com>, Jan Kara <jack@...e.cz>, Ying Han <yinghan@...gle.com>, "hannes@...xchg.org" <hannes@...xchg.org>, Rik van Riel <riel@...hat.com>, Andrea Righi <andrea@...terlinux.com>, Minchan Kim <minchan.kim@...il.com>, Linux Memory Management List <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH 1/9] memcg: add page_cgroup flags for dirty page tracking On Wed, Feb 29, 2012 at 09:50:51AM +0900, KAMEZAWA Hiroyuki wrote: > On Tue, 28 Feb 2012 22:00:23 +0800 > Fengguang Wu <fengguang.wu@...el.com> wrote: > > > From: Greg Thelen <gthelen@...gle.com> > > > > Add additional flags to page_cgroup to track dirty pages > > within a mem_cgroup. > > > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> > > Signed-off-by: Andrea Righi <andrea@...terlinux.com> > > Signed-off-by: Greg Thelen <gthelen@...gle.com> > > Reviewed-by: Minchan Kim <minchan.kim@...il.com> > > Signed-off-by: Fengguang Wu <fengguang.wu@...el.com> > > I'm sorry but I changed the design of page_cgroup's flags update > and never want to add new flags (I'd like to remove page_cgroup->flags.) No sorry - it makes good sense to reuse the native page flags :) > Please see linux-next. > > A good example is PCG_FILE_MAPPED, which I removed. > > memcg: use new logic for page stat accounting > memcg: remove PCG_FILE_MAPPED > > You can make use of PageDirty() and PageWriteback() instead of new flags.. (I hope.) The dirty page accounting is currently done in account_page_dirtied() which is called from __set_page_dirty <= __set_page_dirty_buffers __set_page_dirty_nobuffers ceph_set_page_dirty inside &mapping->tree_lock. TestSetPageDirty() is also called inside &mapping->private_lock. So we'll be including the two mapping locks and possibly &ci->i_ceph_lock if doing move_lock_mem_cgroup(page) # may take &memcg->move_lock TestSetPageDirty(page) update page stats (without any checks) move_unlock_mem_cgroup(page) It should be feasible if that lock dependency is fine. The PG_writeback accounting is very similar to the PG_dirty accounting and can be handled in the same way. Thanks, Fengguang > > --- > > include/linux/page_cgroup.h | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > --- linux.orig/include/linux/page_cgroup.h 2012-02-19 10:53:14.000000000 +0800 > > +++ linux/include/linux/page_cgroup.h 2012-02-19 10:53:16.000000000 +0800 > > @@ -10,6 +10,9 @@ enum { > > /* flags for mem_cgroup and file and I/O status */ > > PCG_MOVE_LOCK, /* For race between move_account v.s. following bits */ > > PCG_FILE_MAPPED, /* page is accounted as "mapped" */ > > + PCG_FILE_DIRTY, /* page is dirty */ > > + PCG_FILE_WRITEBACK, /* page is under writeback */ > > + PCG_FILE_UNSTABLE_NFS, /* page is NFS unstable */ > > __NR_PCG_FLAGS, > > }; > > > > @@ -64,6 +67,10 @@ static inline void ClearPageCgroup##unam > > static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \ > > { return test_and_clear_bit(PCG_##lname, &pc->flags); } > > > > +#define TESTSETPCGFLAG(uname, lname) \ > > +static inline int TestSetPageCgroup##uname(struct page_cgroup *pc) \ > > + { return test_and_set_bit(PCG_##lname, &pc->flags); } > > + > > /* Cache flag is set only once (at allocation) */ > > TESTPCGFLAG(Cache, CACHE) > > CLEARPCGFLAG(Cache, CACHE) > > @@ -77,6 +84,22 @@ SETPCGFLAG(FileMapped, FILE_MAPPED) > > CLEARPCGFLAG(FileMapped, FILE_MAPPED) > > TESTPCGFLAG(FileMapped, FILE_MAPPED) > > > > +SETPCGFLAG(FileDirty, FILE_DIRTY) > > +CLEARPCGFLAG(FileDirty, FILE_DIRTY) > > +TESTPCGFLAG(FileDirty, FILE_DIRTY) > > +TESTCLEARPCGFLAG(FileDirty, FILE_DIRTY) > > +TESTSETPCGFLAG(FileDirty, FILE_DIRTY) > > + > > +SETPCGFLAG(FileWriteback, FILE_WRITEBACK) > > +CLEARPCGFLAG(FileWriteback, FILE_WRITEBACK) > > +TESTPCGFLAG(FileWriteback, FILE_WRITEBACK) > > + > > +SETPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS) > > +CLEARPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS) > > +TESTPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS) > > +TESTCLEARPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS) > > +TESTSETPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS) > > + > > SETPCGFLAG(Migration, MIGRATION) > > CLEARPCGFLAG(Migration, MIGRATION) > > TESTPCGFLAG(Migration, MIGRATION) > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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