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authorQi Zheng <zhengqi.arch@bytedance.com>2023-03-13 19:28:16 +0800
committerAndrew Morton <akpm@linux-foundation.org>2023-03-28 16:20:17 -0700
commit20cd1892fcc3efc10a7ac327cc3790494bec46b5 (patch)
treeaa38d490ea0fb73c38ab972498770467cefb4db3 /mm/shrinker_debug.c
parent475733dda5aedba9e086379aafe6b5ffd53e8f5e (diff)
mm: shrinkers: make count and scan in shrinker debugfs lockless
Like global and memcg slab shrink, also use SRCU to make count and scan operations in memory shrinker debugfs lockless. Link: https://lkml.kernel.org/r/20230313112819.38938-6-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill Tkhai <tkhai@ya.ru> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christian König <christian.koenig@amd.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Sultan Alsawaf <sultan@kerneltoast.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/shrinker_debug.c')
-rw-r--r--mm/shrinker_debug.c25
1 files changed, 8 insertions, 17 deletions
diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c
index 39c3491e28a3..37d54d037495 100644
--- a/mm/shrinker_debug.c
+++ b/mm/shrinker_debug.c
@@ -5,10 +5,12 @@
#include <linux/seq_file.h>
#include <linux/shrinker.h>
#include <linux/memcontrol.h>
+#include <linux/srcu.h>
/* defined in vmscan.c */
extern struct rw_semaphore shrinker_rwsem;
extern struct list_head shrinker_list;
+extern struct srcu_struct shrinker_srcu;
static DEFINE_IDA(shrinker_debugfs_ida);
static struct dentry *shrinker_debugfs_root;
@@ -49,18 +51,13 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
struct mem_cgroup *memcg;
unsigned long total;
bool memcg_aware;
- int ret, nid;
+ int ret = 0, nid, srcu_idx;
count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
if (!count_per_node)
return -ENOMEM;
- ret = down_read_killable(&shrinker_rwsem);
- if (ret) {
- kfree(count_per_node);
- return ret;
- }
- rcu_read_lock();
+ srcu_idx = srcu_read_lock(&shrinker_srcu);
memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE;
@@ -91,8 +88,7 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
}
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
- rcu_read_unlock();
- up_read(&shrinker_rwsem);
+ srcu_read_unlock(&shrinker_srcu, srcu_idx);
kfree(count_per_node);
return ret;
@@ -115,9 +111,8 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
.gfp_mask = GFP_KERNEL,
};
struct mem_cgroup *memcg = NULL;
- int nid;
+ int nid, srcu_idx;
char kbuf[72];
- ssize_t ret;
read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
if (copy_from_user(kbuf, buf, read_len))
@@ -146,11 +141,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
return -EINVAL;
}
- ret = down_read_killable(&shrinker_rwsem);
- if (ret) {
- mem_cgroup_put(memcg);
- return ret;
- }
+ srcu_idx = srcu_read_lock(&shrinker_srcu);
sc.nid = nid;
sc.memcg = memcg;
@@ -159,7 +150,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
shrinker->scan_objects(shrinker, &sc);
- up_read(&shrinker_rwsem);
+ srcu_read_unlock(&shrinker_srcu, srcu_idx);
mem_cgroup_put(memcg);
return size;