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Mon, 06 Mar 2023 22:56:58 -0800 (PST) From: Qi Zheng To: akpm@linux-foundation.org, tkhai@ya.ru, hannes@cmpxchg.org, shakeelb@google.com, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, david@redhat.com, shy828301@gmail.com, rppt@kernel.org Cc: sultan@kerneltoast.com, dave@stgolabs.net, penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: [PATCH v4 5/8] mm: shrinkers: make count and scan in shrinker debugfs lockless Date: Tue, 7 Mar 2023 14:56:02 +0800 Message-Id: <20230307065605.58209-6-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230307065605.58209-1-zhengqi.arch@bytedance.com> References: <20230307065605.58209-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6F1382000F X-Rspam-User: X-Stat-Signature: dzeqpsi59kux4q5wc6np8ipg8d6f5gxi X-HE-Tag: 1678172220-295656 X-HE-Meta: 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 Gck+ak50 oyXq1aiGPmlAFgMAgVsvHiIRrsy0TKpb7e2sl9eeTdv7IE9xqNsYP12yLr8P62zyzAvb0dE8qR6n2hzTlCa61aCcXadhWDoemC0yA8f9OOjVmI6RPHnXe+jYmIw3s+xUVwbyZypvrPpTx/X/Kv1I4LZfx5X9cT3uCWBZTjCw+8kPc4YaWDsn0C9OyehYK3x0AtNOeLh3OzjeXrcjeIHz9ZpqYbleXwdqX9a6DRd8cYxrByHSALhnDrgfYAWKkBGwpX9EShgu1lVVWJardZ15YzFjP8xfs+KNrm7fx32fdpxe/jTHr6dvtQNq6zT9EHpx4agQ/bprIOR9sp+0Crtu+gQbKSIoVYWKe1SPD6O19YNsDNFZ5yAzcudzHsMDd+9gFvY1WnQsReWt6Ha4piZBhdQl0VJfiX5pcX+weanTyPWxXbMI= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Like global and memcg slab shrink, also use SRCU to make count and scan operations in memory shrinker debugfs lockless. Signed-off-by: Qi Zheng --- mm/shrinker_debug.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 39c3491e28a3..6aa7a7ec69da 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -9,6 +9,7 @@ /* 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 +50,13 @@ 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 +87,7 @@ 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 +110,8 @@ 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 +140,7 @@ 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 +149,7 @@ 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; -- 2.20.1