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| author | Yafang Shao <laoar.shao@gmail.com> | 2023-02-14 15:35:49 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-02-16 20:43:55 -0800 |
| commit | 2ef8ed7ddd2e6e69da7802be51af8ad71326a74f (patch) | |
| tree | abf089b7cce04ead6f17bb66efa8c03257a6edd3 /mm/percpu-internal.h | |
| parent | 44081c77e8a4aac9c5a010ed0d9ccdcf684041e1 (diff) | |
| download | lwn-2ef8ed7ddd2e6e69da7802be51af8ad71326a74f.tar.gz lwn-2ef8ed7ddd2e6e69da7802be51af8ad71326a74f.zip | |
mm: percpu: fix incorrect size in pcpu_obj_full_size()
The extra space which is used to store the obj_cgroup membership is only
valid when kmemcg is enabled. The kmemcg can be disabled via the kernel
parameter "cgroup.memory=nokmem" at boot time. This helper is also used
in non-memcg code, for example the tracepoint, so we should fix it.
It was found by code review when I was implementing bpf memory usage[1].
No real issue happens in production environment.
[1]. https://lwn.net/Articles/921991/
Link: https://lkml.kernel.org/r/20230214153549.12291-1-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Vasily Averin <vvs@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/percpu-internal.h')
| -rw-r--r-- | mm/percpu-internal.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index 70b1ea23f4d2..f9847c131998 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/percpu.h> +#include <linux/memcontrol.h> /* * pcpu_block_md is the metadata block struct. @@ -118,14 +119,15 @@ static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk) * @size: size of area to allocate in bytes * * For each accounted object there is an extra space which is used to store - * obj_cgroup membership. Charge it too. + * obj_cgroup membership if kmemcg is not disabled. Charge it too. */ static inline size_t pcpu_obj_full_size(size_t size) { size_t extra_size = 0; #ifdef CONFIG_MEMCG_KMEM - extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *); + if (!mem_cgroup_kmem_disabled()) + extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *); #endif return size * num_possible_cpus() + extra_size; |