Messages in this thread | | | Date | Thu, 15 Jan 2009 17:00:37 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH] mark_page_accessed() in do_swap_page() move latter than memcg charge |
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* KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [2009-01-15 20:08:36]:
> > sorry for late responce. > > > > In this case we've hit a case where the page is valid and the pc is > > > not. This does fix the problem, but won't this impact us getting > > > correct reclaim stats and thus indirectly impact the working of > > > pressure? > > > > > - If retruns NULL, only global LRU's status is updated. > > > > Because this page is not belongs to any memcg, we cannot update > > any counters. But yes, your point is a concern. > > > > Maybe moving acitvate_page() to > > == > > do_swap_page() > > { > > > > - activate_page() > > mem_cgroup_try_charge().. > > .... > > mem_cgroup_commit_charge().... > > .... > > + activate_page() > > } > > == > > is necessary. How do you think, kosaki ? > > > OK. it makes sense. and my test found no bug. > > == > > mark_page_accessed() update reclaim_stat statics. > but currently, memcg charge is called after mark_page_accessed(). > > then, mark_page_accessed() don't update memcg statics correctly. > > fixing here. >
Changelog needs to be a bit more elaborate, may be talk about invalid pointer we hit if mark_page_accessed is not moved, etc.
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> > Cc: Balbir Singh <balbir@linux.vnet.ibm.com> > > --- > mm/memory.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > Index: b/mm/memory.c > =================================================================== > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2426,8 +2426,6 @@ static int do_swap_page(struct mm_struct > count_vm_event(PGMAJFAULT); > } > > - mark_page_accessed(page); > - > lock_page(page); > delayacct_clear_flag(DELAYACCT_PF_SWAPIN); > > @@ -2480,6 +2478,8 @@ static int do_swap_page(struct mm_struct > try_to_free_swap(page); > unlock_page(page); > > + mark_page_accessed(page); > + > if (write_access) { > ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); > if (ret & VM_FAULT_ERROR) > > >
Looks good to me otherwise
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
-- Balbir
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