* [withdrawn] mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix.patch removed from -mm tree
@ 2021-03-31 22:28 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2021-03-31 22:28 UTC (permalink / raw)
To: david, guro, hannes, hughd, ktkhai, mhocko, mm-commits,
oliver.sang, shakeelb, shy828301, vbabka
The patch titled
Subject: mm: vmscan: fix shrinker_rwsem in free_shrinker_info()
has been removed from the -mm tree. Its filename was
mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix.patch
This patch was dropped because it was withdrawn
------------------------------------------------------
From: Hugh Dickins <hughd@google.com>
Subject: mm: vmscan: fix shrinker_rwsem in free_shrinker_info()
Lockdep warns mm/vmscan.c: suspicious rcu_dereference_protected() usage!
when free_shrinker_info() is called from mem_cgroup_css_free(): there it
is called with no locking, whereas alloc_shrinker_info() calls it with
down_write of shrinker_rwsem - which seems appropriate. Rearrange that
so free_shrinker_info() can manage the shrinker_rwsem for itself.
Link: https://lkml.kernel.org/r/20210317140615.GB28839@xsang-OptiPlex-9020
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2103301640240.2584@eggly.anvils
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/vmscan.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix
+++ a/mm/vmscan.c
@@ -249,18 +249,20 @@ void free_shrinker_info(struct mem_cgrou
struct shrinker_info *info;
int nid;
+ down_write(&shrinker_rwsem);
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
info = shrinker_info_protected(memcg, nid);
kvfree(info);
rcu_assign_pointer(pn->shrinker_info, NULL);
}
+ up_write(&shrinker_rwsem);
}
int alloc_shrinker_info(struct mem_cgroup *memcg)
{
struct shrinker_info *info;
- int nid, size, ret = 0;
+ int nid, size;
int map_size, defer_size = 0;
down_write(&shrinker_rwsem);
@@ -270,9 +272,9 @@ int alloc_shrinker_info(struct mem_cgrou
for_each_node(nid) {
info = kvzalloc_node(sizeof(*info) + size, GFP_KERNEL, nid);
if (!info) {
+ up_write(&shrinker_rwsem);
free_shrinker_info(memcg);
- ret = -ENOMEM;
- break;
+ return -ENOMEM;
}
info->nr_deferred = (atomic_long_t *)(info + 1);
info->map = (void *)info->nr_deferred + defer_size;
@@ -280,7 +282,7 @@ int alloc_shrinker_info(struct mem_cgrou
}
up_write(&shrinker_rwsem);
- return ret;
+ return 0;
}
static inline bool need_expand(int nr_max)
_
Patches currently in -mm which might be from hughd@google.com are
mm-restore-node-stat-checking-in-proc-sys-vm-stat_refresh.patch
mm-no-more-einval-from-proc-sys-vm-stat_refresh.patch
mm-proc-sys-vm-stat_refresh-skip-checking-known-negative-stats.patch
mm-proc-sys-vm-stat_refresh-stop-checking-monotonic-numa-stats.patch
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2021-03-31 22:28 [withdrawn] mm-vmscan-add-per-memcg-shrinker-nr_deferred-fix.patch removed from -mm tree akpm
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