The patch titled
Subject: Re: memcg: prevent from OOM with too many dirty pages
has been removed from the -mm tree. Its filename was
memcg-prevent-oom-with-too-many-dirty-pages-fix-fix.patch
This patch was dropped because it was folded into memcg-prevent-oom-with-too-many-dirty-pages.patch
------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: Re: memcg: prevent from OOM with too many dirty pages
On Wed, 11 Jul 2012, Andrew Morton wrote:
> On Wed, 11 Jul 2012 18:57:43 -0700 (PDT) Hugh Dickins <hughd@xxxxxxxxxx> wrote:
>
> > --- 3.5-rc6-mm1/mm/vmscan.c 2012-07-11 14:42:13.668335884 -0700
> > +++ linux/mm/vmscan.c 2012-07-11 16:01:20.712814127 -0700
> > @@ -726,7 +726,8 @@ static unsigned long shrink_page_list(st
> > * writeback from reclaim and there is nothing else to
> > * reclaim.
> > */
> > - if (!global_reclaim(sc) && PageReclaim(page))
> > + if (!global_reclaim(sc) && PageReclaim(page) &&
> > + may_enter_fs)
> > wait_on_page_writeback(page);
> > else {
> > nr_writeback++;
>
> um, that may_enter_fs test got removed because nobody knew why it was
> there. Nobody knew why it was there because it was undocumented. Do
> you see where I'm going with this?
I was hoping you might do that bit ;) Here's my display of ignorance:
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 6 ++++++
1 file changed, 6 insertions(+)
diff -puN mm/vmscan.c~memcg-prevent-oom-with-too-many-dirty-pages-fix-fix mm/vmscan.c
--- a/mm/vmscan.c~memcg-prevent-oom-with-too-many-dirty-pages-fix-fix
+++ a/mm/vmscan.c
@@ -725,6 +725,12 @@ static unsigned long shrink_page_list(st
* could easily OOM just because too many pages are in
* writeback from reclaim and there is nothing else to
* reclaim.
+ *
+ * Check may_enter_fs, certainly because a loop driver
+ * thread might enter reclaim, and deadlock if it waits
+ * on a page for which it is needed to do the write
+ * (loop masks off __GFP_IO|__GFP_FS for this reason);
+ * but more thought would probably show more reasons.
*/
if (!global_reclaim(sc) && PageReclaim(page) &&
may_enter_fs)
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
origin.patch
memcg-rename-mem_cgroup_stat_swapout-as-mem_cgroup_stat_swap.patch
memcg-remove-mem_cgroup_charge_type_force.patch
swap-allow-swap-readahead-to-be-merged.patch
documentation-update-how-page-cluster-affects-swap-i-o.patch
memcg-prevent-oom-with-too-many-dirty-pages.patch
mm-fadvise-dont-return-einval-when-filesystem-cannot-implement-fadvise.patch
memcg-rename-config-variables.patch
memcg-rename-config-variables-fix.patch
memcg-rename-config-variables-fix-fix.patch
shmem-provide-vm_ops-when-also-providing-a-mem-policy.patch
tmpfs-interleave-the-starting-node-of-dev-shmem.patch
prio_tree-debugging-patch.patch
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