From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5284C6FD19 for ; Mon, 13 Mar 2023 19:10:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229871AbjCMTKy (ORCPT ); Mon, 13 Mar 2023 15:10:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229826AbjCMTKn (ORCPT ); Mon, 13 Mar 2023 15:10:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09D1D37F31 for ; Mon, 13 Mar 2023 12:10:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AFC61B811F6 for ; Mon, 13 Mar 2023 19:10:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AC6EC433D2; Mon, 13 Mar 2023 19:10:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678734634; bh=3dm5x+gO/o5+2XklVJo3TdX3hhQihUGNuJeeNQKu5yE=; h=Date:To:From:Subject:From; b=FCRCmjfLk22duurIQjY1S1In6ZqwY0Zh5VET1yTA9YKwjuccMOgDsF3JJXl2vMR/M jCfg5Tz3VfFRwC6NX2vbw2n1y6YKy+FmxO1a22DyM/8UbHfTjSGemvuFR9uer4kdwn Js5d6nGNuKdoXqF1HB7ypMOrVpatbjUwF2S51MXM= Date: Mon, 13 Mar 2023 12:10:33 -0700 To: mm-commits@vger.kernel.org, vbabka@suse.cz, tkhai@ya.ru, sultan@kerneltoast.com, shy828301@gmail.com, shakeelb@google.com, roman.gushchin@linux.dev, penguin-kernel@i-love.sakura.ne.jp, paulmck@kernel.org, muchun.song@linux.dev, mhocko@kernel.org, hannes@cmpxchg.org, david@redhat.com, dave@stgolabs.net, christian.koenig@amd.com, zhengqi.arch@bytedance.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-shrinkers-make-count-and-scan-in-shrinker-debugfs-lockless.patch added to mm-unstable branch Message-Id: <20230313191034.6AC6EC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: shrinkers: make count and scan in shrinker debugfs lockless has been added to the -mm mm-unstable branch. Its filename is mm-shrinkers-make-count-and-scan-in-shrinker-debugfs-lockless.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shrinkers-make-count-and-scan-in-shrinker-debugfs-lockless.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Qi Zheng Subject: mm: shrinkers: make count and scan in shrinker debugfs lockless Date: Mon, 13 Mar 2023 19:28:16 +0800 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 Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai Cc: Christian König Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Paul E. McKenney Cc: Roman Gushchin Cc: Shakeel Butt Cc: Sultan Alsawaf Cc: Tetsuo Handa Cc: Yang Shi Signed-off-by: Andrew Morton --- --- a/mm/shrinker_debug.c~mm-shrinkers-make-count-and-scan-in-shrinker-debugfs-lockless +++ a/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(s 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(s } } 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_wri .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_wri 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_wri shrinker->scan_objects(shrinker, &sc); - up_read(&shrinker_rwsem); + srcu_read_unlock(&shrinker_srcu, srcu_idx); mem_cgroup_put(memcg); return size; _ Patches currently in -mm which might be from zhengqi.arch@bytedance.com are mm-vmscan-add-a-map_nr_max-field-to-shrinker_info.patch mm-vmscan-make-global-slab-shrink-lockless.patch mm-vmscan-make-memcg-slab-shrink-lockless.patch mm-shrinkers-make-count-and-scan-in-shrinker-debugfs-lockless.patch mm-vmscan-hold-write-lock-to-reparent-shrinker-nr_deferred.patch mm-vmscan-remove-shrinker_rwsem-from-synchronize_shrinkers.patch mm-shrinkers-convert-shrinker_rwsem-to-mutex.patch