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Mon, 13 Mar 2023 04:30:09 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.229]) by smtp.gmail.com with ESMTPSA id n2-20020a654882000000b0050300a7c8c2sm4390827pgs.89.2023.03.13.04.30.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Mar 2023 04:30:08 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, tkhai@ya.ru, vbabka@suse.cz, christian.koenig@amd.com, 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 v5 5/8] mm: shrinkers: make count and scan in shrinker debugfs lockless Date: Mon, 13 Mar 2023 19:28:16 +0800 Message-Id: <20230313112819.38938-6-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230313112819.38938-1-zhengqi.arch@bytedance.com> References: <20230313112819.38938-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 759D240021 X-Stat-Signature: ufhggeshqscatzygiqeqqnx6xnbuu77w X-HE-Tag: 1678707010-780958 X-HE-Meta: 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 IZaU4hwa LOt62SJ4lc1roGzxCZpReYILI2ike9/G33pfJ0r+60mg2flnpsqEtAtTLz+oapGWkBbYXuSVBVhAD4gsM9Q24xxsM2igq6h2AMkiZFOkKkF8uwM9fYxD11d9dlQJmBagl3BLg1uBwWiTVdkzMfzhzRQY0HgCYPV1KP9tKm2Tdc24LfJuJ4IRCyL5aZmQnAbb/AdFLfgeyiP74MWG6V/O29TPlo2+WpQ09stJ8S9//OjRVkPsG6BybTPiUSOQ+qMvdYbV4qV/fyhZlKM15R+RkrtwS+SJpOwD4NGpeMtQafgij83CkupIuHurfsYeFXUIkdaZE7dsQoGGLEy+e1zlBRW6fa6skSF91K0SYKKix/Dfp1u6xO4VZFRo59Hct7Rys9bwaH0mAg5cMCartx8+aapH13wrbbYfdIWKXqsIwkAUAdAn0t34AgjpYn//Km7s0XNuNgBDnCmkilzU8S5KteR6T8I2kOr5NJqYeq5GzlxG3TfM= 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 Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai --- mm/shrinker_debug.c | 25 ++++++++----------------- 1 file 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 #include #include +#include /* 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;