diff options
| author |   Zeng Jingxiang <linuszeng@tencent.com> | 2025-02-27 16:22:23 +0800 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2025-03-17 00:05:32 -0700 |
| commit | b9585a3f3e0b30b3b60c85dc39f27ed3b06fb623 (patch) | |
| tree | 79a1c0063c3b7bad76a060dae2b8996f74c40131 | |
| parent | mm: rename GENERIC_PTDUMP and PTDUMP_CORE (diff) | |
| download | wireguard-linux-b9585a3f3e0b30b3b60c85dc39f27ed3b06fb623.tar.xz wireguard-linux-b9585a3f3e0b30b3b60c85dc39f27ed3b06fb623.zip | |
mm/list_lru: make the case where mlru is NULL as unlikely
In the following memcg_list_lru_alloc() function, mlru here is almost
always NULL, so in most cases this should save a function call, mark mlru
as unlikely to optimize the code, and reusing the mlru for the next
attempt when the tree insertion fails.
do {
xas_lock_irqsave(&xas, flags);
if (!xas_load(&xas) && !css_is_dying(&pos->css)) {
xas_store(&xas, mlru);
if (!xas_error(&xas))
mlru = NULL;
}
xas_unlock_irqrestore(&xas, flags);
} while (xas_nomem(&xas, GFP_KERNEL));
> if (mlru)
kfree(mlru);
Link: https://lkml.kernel.org/r/20250227082223.1173847-1-jingxiangzeng.cas@gmail.com
Signed-off-by: Zeng Jingxiang <linuszeng@tencent.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412290924.UTP7GH2Z-lkp@intel.com/
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Jingxiang Zeng <linuszeng@tencent.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/list_lru.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c index 7d69434c70e0..490473af3122 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -510,7 +510,7 @@ int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, gfp_t gfp) { unsigned long flags; - struct list_lru_memcg *mlru; + struct list_lru_memcg *mlru = NULL; struct mem_cgroup *pos, *parent; XA_STATE(xas, &lru->xa, 0); @@ -535,9 +535,11 @@ int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, parent = parent_mem_cgroup(pos); } - mlru = memcg_init_list_lru_one(lru, gfp); - if (!mlru) - return -ENOMEM; + if (!mlru) { + mlru = memcg_init_list_lru_one(lru, gfp); + if (!mlru) + return -ENOMEM; + } xas_set(&xas, pos->kmemcg_id); do { xas_lock_irqsave(&xas, flags); @@ -548,10 +550,11 @@ int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, } xas_unlock_irqrestore(&xas, flags); } while (xas_nomem(&xas, gfp)); - if (mlru) - kfree(mlru); } while (pos != memcg && !css_is_dying(&pos->css)); + if (unlikely(mlru)) + kfree(mlru); + return xas_error(&xas); } #else |