[v7 PATCH 06/12] mm: vmscan: add shrinker_info_protected() helper
From: Yang Shi <hidden>
Date: 2021-02-09 18:05:10
Also in:
linux-fsdevel, lkml
Subsystem:
memory management, memory management - mglru (multi-gen lru), memory management - reclaim, the rest · Maintainers:
Andrew Morton, Johannes Weiner, Linus Torvalds
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. Signed-off-by: Yang Shi <redacted> --- mm/vmscan.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9436f9246d32..273efbf4d53c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c@@ -190,6 +190,13 @@ static int shrinker_nr_max; #define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \ (DIV_ROUND_UP(nr_max, 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 void free_shrinker_info_rcu(struct rcu_head *head) { kvfree(container_of(head, struct shrinker_info, rcu));
@@ -202,8 +209,7 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg, int nid; for_each_node(nid) { - old = rcu_dereference_protected( - mem_cgroup_nodeinfo(memcg, nid)->shrinker_info, true); + old = shrinker_info_protected(memcg, nid); /* Not yet online memcg */ if (!old) return 0;
@@ -234,7 +240,7 @@ void free_shrinker_info(struct mem_cgroup *memcg) for_each_node(nid) { pn = mem_cgroup_nodeinfo(memcg, nid); - info = rcu_dereference_protected(pn->shrinker_info, true); + info = shrinker_info_protected(memcg, nid); kvfree(info); rcu_assign_pointer(pn->shrinker_info, NULL); }
@@ -674,8 +680,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, 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;
--
2.26.2