The patch titled
Subject: mm: vmscan: add shrinker_info_protected() helper
has been added to the -mm tree. Its filename is
mm-vmscan-add-shrinker_info_protected-helper.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-add-shrinker_info_protected-helper.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-add-shrinker_info_protected-helper.patch
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------------------------------------------------------
From: Yang Shi <shy828301@xxxxxxxxx>
Subject: mm: vmscan: add shrinker_info_protected() helper
The shrinker_info is dereferenced in a couple of places via
rcu_dereference_protected with different calling conventions, for example,
using mem_cgroup_nodeinfo helper or dereferencing
memcg->nodeinfo[nid]->shrinker_info. And the later patch will add more
dereference places.
So extract the dereference into a helper to make the code more readable.
No functional change.
Link: https://lkml.kernel.org/r/20210311190845.9708-8-shy828301@xxxxxxxxx
Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-add-shrinker_info_protected-helper
+++ a/mm/vmscan.c
@@ -192,6 +192,13 @@ static inline int shrinker_map_size(int
return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long));
}
+static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
+ int nid)
+{
+ return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+ lockdep_is_held(&shrinker_rwsem));
+}
+
static int expand_one_shrinker_info(struct mem_cgroup *memcg,
int size, int old_size)
{
@@ -201,7 +208,7 @@ static int expand_one_shrinker_info(stru
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
- old = rcu_dereference_protected(pn->shrinker_info, true);
+ old = shrinker_info_protected(memcg, nid);
/* Not yet online memcg */
if (!old)
return 0;
@@ -232,7 +239,7 @@ void free_shrinker_info(struct mem_cgrou
for_each_node(nid) {
pn = memcg->nodeinfo[nid];
- info = rcu_dereference_protected(pn->shrinker_info, true);
+ info = shrinker_info_protected(memcg, nid);
kvfree(info);
rcu_assign_pointer(pn->shrinker_info, NULL);
}
@@ -675,8 +682,7 @@ static unsigned long shrink_slab_memcg(g
if (!down_read_trylock(&shrinker_rwsem))
return 0;
- info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
- true);
+ info = shrinker_info_protected(memcg, nid);
if (unlikely(!info))
goto unlock;
_
Patches currently in -mm which might be from shy828301@xxxxxxxxx are
mm-vmscan-use-nid-from-shrink_control-for-tracepoint.patch
mm-vmscan-consolidate-shrinker_maps-handling-code.patch
mm-vmscan-use-shrinker_rwsem-to-protect-shrinker_maps-allocation.patch
mm-vmscan-remove-memcg_shrinker_map_size.patch
mm-vmscan-use-kvfree_rcu-instead-of-call_rcu.patch
mm-memcontrol-rename-shrinker_map-to-shrinker_info.patch
mm-vmscan-add-shrinker_info_protected-helper.patch
mm-vmscan-use-a-new-flag-to-indicate-shrinker-is-registered.patch
mm-vmscan-add-per-memcg-shrinker-nr_deferred.patch
mm-vmscan-use-per-memcg-nr_deferred-of-shrinker.patch
mm-vmscan-dont-need-allocate-shrinker-nr_deferred-for-memcg-aware-shrinkers.patch
mm-memcontrol-reparent-nr_deferred-when-memcg-offline.patch
mm-vmscan-shrink-deferred-objects-proportional-to-priority.patch
