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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>
This commit is contained in:
Qi Zheng 2023-03-13 19:28:16 +08:00 committed by Andrew Morton
parent 475733dda5
commit 20cd1892fc
1 changed files with 8 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
mm/shrinker_debug.c
View File

@ -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;