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Sun, 26 Feb 2023 06:48:39 -0800 (PST) Received: from localhost.localdomain ([139.177.225.248]) by smtp.gmail.com with ESMTPSA id y20-20020a170902ed5400b0019c2cf12d15sm2755589plb.116.2023.02.26.06.48.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 06:48:39 -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 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 v3 5/8] mm: shrinkers: make count and scan in shrinker debugfs lockless Date: Sun, 26 Feb 2023 22:46:52 +0800 Message-Id: <20230226144655.79778-6-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230226144655.79778-1-zhengqi.arch@bytedance.com> References: <20230226144655.79778-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 1B113180013 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: gxhqj7g94qxwj13humb5h6gwje4q8ta9 X-HE-Tag: 1677422919-36286 X-HE-Meta: U2FsdGVkX18y8t0cXSbuuzdF+UOTqIfG57CcBs/vhYScDxv4cTh6+/kYzvrY+MPskkzqqXBtMCKoReL/RzilwJYVomSKqv+fUpIYf6rmjQGJjxHGrFBWX1BFxjUJm4UwJgmQa5vS879K2+73thsCVM87RLrCGRKl6Wu+GNRlB1iWAik01seVFpRdAPjT6XoiGyzsrnTlrsipl6xTSl1bRrlSdlBY8J5YnmfqsaA1jkzn5H9GDJ/dlPeDbgxHIdtNlWv+KJWcnFR6UjvZ8yrGWKTJhgm318YaYO3Pgx4ukQ98oxvrZ9he2e2kCp292sclVxrOnOHoMzppi7Ld6Vh7JF3qfaNFiDG4k36wz9Av8A9+w5Bck74vR7qX6ATElxmYul5TcpfFZctTEmoNA2qe2y0ZYRO4VMj5uQEZnhN5vxFLpJySjf3VVi33IyUthIEZ98z9VY9MXLjAwnydb0YGkuE76U6orGQ447e7ECSliVlCgHEzwKlaTHIOjRG0Na0sxaR6hL1XX9q9E6mADbX/2cwrIM61OtLZ6bdZdwXqtJq1L/g+bqq9YwjDRQnzuhXoS6MvOXZx5T9wSapSm10l1Dvq6GPn6qltZDE/3CUbgTTVS5/My6tnq0XdFDtlDpcqQaVzlmAM34RiBzEf3KPGFuPAvfnI3FtVPwWNK4m2FwIpfoQBJ7phv5S4g756GVLmA/HKDrZ6S8WYAvUh6JE8MiNWGVhBG98dggXCO1dZJ4sRR9pRyJUJdKZdAL8KL+lyMxGZgfPsbXEt3e6JnJv8GCPr6nGMUdPG37y8JZXm0W+2EM8c6qIpID1lIpfg1gLSF2JwQ8SKhWDVZ4fYOAE/uyFMPeWybcd5EGbyVWgpz1I/35OlvnbJ/9VqNh/RG51ErZxtqXOQLjaEnExaEP5drxqj83ekqKbwC0EaYQHMgwCXO/wiWncmvROKdp+C2AIprxMqp1e5g1yV9d7ZcsG Xm1yIHU9 IdS5TRvqVmwcuynp5yvgeyF6MKq5ENkCO2Kf+fQIGnicmYFQlsnSxuVUN0g4NZkOFeWjGMnrUT49pvE1O7gA96rk1eeOW9Pfp8W5JqPU0k7EfD4eoMKbj0JiJn1AwY4qoIp4tkv/csbtJky8xLslAHwyEI++3gvo3ulzCblvHZl9Xy4I6Dlh2E5oxMZk4Xg48hOjsoiqFqB4EPEUFaObv4k6eZqaCiO7wJhyPVeg0tq2M+Sbnesg+K2HYQkjUGO5+iH4bP2Lv3dcr9uH3ORKug2knJRqJjryHdz/R3NDAvuGHbQ/gAeelxocBgH9pE0dHgBZLQh132OdIC6V1ker7pN7Fpjg0Yv58GU+FUOI82z0YIFPtMZcFCPT/3f0beAnv4ct0o5t2LnME1ox4AsLLhoTXHxYcMSj0JWk2r16+SrysyjE= 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;