Messages in this thread | | | Date | Sun, 4 Mar 2012 09:29:52 +0800 | From | Fengguang Wu <> | Subject | Re: [PATCH 1/9] memcg: add page_cgroup flags for dirty page tracking |
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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@intel.com> wrote: > > > From: Greg Thelen <gthelen@google.com> > > > > Add additional flags to page_cgroup to track dirty pages > > within a mem_cgroup. > > > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > Signed-off-by: Andrea Righi <andrea@betterlinux.com> > > Signed-off-by: Greg Thelen <gthelen@google.com> > > Reviewed-by: Minchan Kim <minchan.kim@gmail.com> > > Signed-off-by: Fengguang Wu <fengguang.wu@intel.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) > > > > > >
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