Subject: [folded-merged] memcg-enhance-memcg-iterator-to-support-predicates-fix.patch removed from -mm tree
To: hughd@xxxxxxxxxx,hannes@xxxxxxxxxxx,kamezawa.hiroyu@xxxxxxxxxxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,mhocko@xxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 12 Sep 2013 15:03:08 -0700
The patch titled
Subject: mm: fix memcg-less page reclaim
has been removed from the -mm tree. Its filename was
memcg-enhance-memcg-iterator-to-support-predicates-fix.patch
This patch was dropped because it was folded into memcg-enhance-memcg-iterator-to-support-predicates.patch
------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm: fix memcg-less page reclaim
Now that everybody loves memcg, configures it on, and would not dream
of booting with cgroup_disable=memory, it can pass unnoticed for weeks
that memcg-less page reclaim is completely broken.
mmotm's "memcg: enhance memcg iterator to support predicates" replaces
__shrink_zone()'s "do { } while (memcg);" loop by a "while (memcg) {}"
loop: which is nicer for memcg, but does nothing for !CONFIG_MEMCG or
cgroup_disable=memory. Page reclaim hangs, making no progress.
Adding mem_cgroup_disabled() and once++ test there is ugly. Ideally,
even a !CONFIG_MEMCG build might in future have a stub root_mem_cgroup,
which would get around this: but that's not so at present.
However, it appears that nothing actually dereferences the memcg pointer
in the mem_cgroup_disabled() case, here or anywhere else that case can
reach mem_cgroup_iter() (mem_cgroup_iter_break() is not called in
global reclaim).
So, simply pass back an ordinarily-oopsing non-NULL address the first
time, and we shall hear about it if I'm wrong.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 3 ++-
mm/memcontrol.c | 6 ++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff -puN include/linux/memcontrol.h~memcg-enhance-memcg-iterator-to-support-predicates-fix include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~memcg-enhance-memcg-iterator-to-support-predicates-fix
+++ a/include/linux/memcontrol.h
@@ -328,7 +328,8 @@ mem_cgroup_iter_cond(struct mem_cgroup *
struct mem_cgroup_reclaim_cookie *reclaim,
mem_cgroup_iter_filter cond)
{
- return NULL;
+ /* first call must return non-NULL, second return NULL */
+ return (struct mem_cgroup *)(unsigned long)!prev;
}
static inline struct mem_cgroup *
diff -puN mm/memcontrol.c~memcg-enhance-memcg-iterator-to-support-predicates-fix mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-enhance-memcg-iterator-to-support-predicates-fix
+++ a/mm/memcontrol.c
@@ -1018,8 +1018,10 @@ struct mem_cgroup *mem_cgroup_iter_cond(
struct mem_cgroup *memcg = NULL;
struct mem_cgroup *last_visited = NULL;
- if (mem_cgroup_disabled())
- return NULL;
+ if (mem_cgroup_disabled()) {
+ /* first call must return non-NULL, second return NULL */
+ return (struct mem_cgroup *)(unsigned long)!prev;
+ }
if (!root)
root = root_mem_cgroup;
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
origin.patch
memcg-vmscan-integrate-soft-reclaim-tighter-with-zone-shrinking-code.patch
memcg-get-rid-of-soft-limit-tree-infrastructure.patch
vmscan-memcg-do-softlimit-reclaim-also-for-targeted-reclaim.patch
memcg-enhance-memcg-iterator-to-support-predicates.patch
memcg-track-children-in-soft-limit-excess-to-improve-soft-limit.patch
memcg-vmscan-do-not-attempt-soft-limit-reclaim-if-it-would-not-scan-anything.patch
memcg-track-all-children-over-limit-in-the-root.patch
memcg-vmscan-do-not-fall-into-reclaim-all-pass-too-quickly.patch
thp-account-anon-transparent-huge-pages-into-nr_anon_pages.patch
mm-cleanup-add_to_page_cache_locked.patch
thp-move-maybe_pmd_mkwrite-out-of-mk_huge_pmd.patch
thp-do_huge_pmd_anonymous_page-cleanup.patch
thp-consolidate-code-between-handle_mm_fault-and-do_huge_pmd_anonymous_page.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
