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 D6DA3C678D5 for ; Tue, 7 Mar 2023 22:27:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229535AbjCGW1Q (ORCPT ); Tue, 7 Mar 2023 17:27:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229794AbjCGW0n (ORCPT ); Tue, 7 Mar 2023 17:26:43 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF72D93E3A for ; Tue, 7 Mar 2023 14:26:14 -0800 (PST) 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 sin.source.kernel.org (Postfix) with ESMTPS id C927BCE1D59 for ; Tue, 7 Mar 2023 22:25:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C533C433D2; Tue, 7 Mar 2023 22:25:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678227935; bh=M2hPEYk/srbcLK6NCkBeAtTIj9T/yz08HIdLtQRB1uY=; h=Date:To:From:Subject:From; b=Zpfgg+J91wZQUBwGmzNaIiGh+8/6xmr4GE5Urli34YzW24Cp+zkSDXFvOke3ErYR1 q2UL5IOdtawOE80DMauzdmtbvMxhWO3/cNiGokjWsX0mjVpi/uhOeLhR0rcJVpJSzp J/v5clQaVrRI0kwKx3R/Ux7vAGhW6o7zkRlFVQWM= Date: Tue, 07 Mar 2023 14:25:34 -0800 To: mm-commits@vger.kernel.org, tkhai@ya.ru, sultan@kerneltoast.com, shy828301@gmail.com, shakeelb@google.com, rppt@kernel.org, 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, zhengqi.arch@bytedance.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-shrinkers-convert-shrinker_rwsem-to-mutex.patch added to mm-unstable branch Message-Id: <20230307222535.3C533C433D2@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: convert shrinker_rwsem to mutex has been added to the -mm mm-unstable branch. Its filename is mm-shrinkers-convert-shrinker_rwsem-to-mutex.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shrinkers-convert-shrinker_rwsem-to-mutex.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: convert shrinker_rwsem to mutex Date: Tue, 7 Mar 2023 14:56:05 +0800 Now there are no readers of shrinker_rwsem, so we can simply replace it with mutex lock. Link: https://lkml.kernel.org/r/20230307065605.58209-9-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Kirill Tkhai Cc: Michal Hocko Cc: Mike Rapoport 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 --- drivers/md/dm-cache-metadata.c | 2 - drivers/md/dm-thin-metadata.c | 2 - fs/super.c | 2 - mm/shrinker_debug.c | 14 ++++++------ mm/vmscan.c | 34 +++++++++++++++---------------- 5 files changed, 27 insertions(+), 27 deletions(-) --- a/drivers/md/dm-cache-metadata.c~mm-shrinkers-convert-shrinker_rwsem-to-mutex +++ a/drivers/md/dm-cache-metadata.c @@ -1828,7 +1828,7 @@ int dm_cache_metadata_abort(struct dm_ca * Replacement block manager (new_bm) is created and old_bm destroyed outside of * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs cmd root_lock). - * - must take shrinker_rwsem without holding cmd->root_lock + * - must take shrinker_mutex without holding cmd->root_lock */ new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, CACHE_MAX_CONCURRENT_LOCKS); --- a/drivers/md/dm-thin-metadata.c~mm-shrinkers-convert-shrinker_rwsem-to-mutex +++ a/drivers/md/dm-thin-metadata.c @@ -1887,7 +1887,7 @@ int dm_pool_abort_metadata(struct dm_poo * Replacement block manager (new_bm) is created and old_bm destroyed outside of * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs pmd root_lock). - * - must take shrinker_rwsem without holding pmd->root_lock + * - must take shrinker_mutex without holding pmd->root_lock */ new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT, THIN_MAX_CONCURRENT_LOCKS); --- a/fs/super.c~mm-shrinkers-convert-shrinker_rwsem-to-mutex +++ a/fs/super.c @@ -54,7 +54,7 @@ static char *sb_writers_name[SB_FREEZE_L * One thing we have to be careful of with a per-sb shrinker is that we don't * drop the last active reference to the superblock from within the shrinker. * If that happens we could trigger unregistering the shrinker from within the - * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we + * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we * take a passive reference to the superblock to avoid this from occurring. */ static unsigned long super_cache_scan(struct shrinker *shrink, --- a/mm/shrinker_debug.c~mm-shrinkers-convert-shrinker_rwsem-to-mutex +++ a/mm/shrinker_debug.c @@ -7,7 +7,7 @@ #include /* defined in vmscan.c */ -extern struct rw_semaphore shrinker_rwsem; +extern struct mutex shrinker_mutex; extern struct list_head shrinker_list; extern struct srcu_struct shrinker_srcu; @@ -167,7 +167,7 @@ int shrinker_debugfs_add(struct shrinker char buf[128]; int id; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); /* debugfs isn't initialized yet, add debugfs entries later. */ if (!shrinker_debugfs_root) @@ -210,7 +210,7 @@ int shrinker_debugfs_rename(struct shrin if (!new) return -ENOMEM; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); old = shrinker->name; shrinker->name = new; @@ -228,7 +228,7 @@ int shrinker_debugfs_rename(struct shrin shrinker->debugfs_entry = entry; } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); kfree_const(old); @@ -240,7 +240,7 @@ struct dentry *shrinker_debugfs_remove(s { struct dentry *entry = shrinker->debugfs_entry; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); kfree_const(shrinker->name); shrinker->name = NULL; @@ -265,14 +265,14 @@ static int __init shrinker_debugfs_init( shrinker_debugfs_root = dentry; /* Create debugfs entries for shrinkers registered at boot */ - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_for_each_entry(shrinker, &shrinker_list, list) if (!shrinker->debugfs_entry) { ret = shrinker_debugfs_add(shrinker); if (ret) break; } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } --- a/mm/vmscan.c~mm-shrinkers-convert-shrinker_rwsem-to-mutex +++ a/mm/vmscan.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include #include @@ -202,7 +202,7 @@ static void set_task_reclaim_state(struc } LIST_HEAD(shrinker_list); -DECLARE_RWSEM(shrinker_rwsem); +DEFINE_MUTEX(shrinker_mutex); DEFINE_SRCU(shrinker_srcu); static atomic_t shrinker_srcu_generation = ATOMIC_INIT(0); @@ -225,7 +225,7 @@ static struct shrinker_info *shrinker_in { return srcu_dereference_check(memcg->nodeinfo[nid]->shrinker_info, &shrinker_srcu, - lockdep_is_held(&shrinker_rwsem)); + lockdep_is_held(&shrinker_mutex)); } static struct shrinker_info *shrinker_info_srcu(struct mem_cgroup *memcg, @@ -310,7 +310,7 @@ int alloc_shrinker_info(struct mem_cgrou int nid, size, ret = 0; int map_size, defer_size = 0; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); map_size = shrinker_map_size(shrinker_nr_max); defer_size = shrinker_defer_size(shrinker_nr_max); size = map_size + defer_size; @@ -326,7 +326,7 @@ int alloc_shrinker_info(struct mem_cgrou info->map_nr_max = shrinker_nr_max; rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } @@ -342,7 +342,7 @@ static int expand_shrinker_info(int new_ if (!root_mem_cgroup) goto out; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); map_size = shrinker_map_size(new_nr_max); defer_size = shrinker_defer_size(new_nr_max); @@ -392,7 +392,7 @@ static int prealloc_memcg_shrinker(struc if (mem_cgroup_disabled()) return -ENOSYS; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL); if (id < 0) goto unlock; @@ -406,7 +406,7 @@ static int prealloc_memcg_shrinker(struc shrinker->id = id; ret = 0; unlock: - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } @@ -416,7 +416,7 @@ static void unregister_memcg_shrinker(st BUG_ON(id < 0); - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); idr_remove(&shrinker_idr, id); } @@ -451,7 +451,7 @@ void reparent_shrinker_deferred(struct m parent = root_mem_cgroup; /* Prevent from concurrent shrinker_info expand */ - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); @@ -460,7 +460,7 @@ void reparent_shrinker_deferred(struct m atomic_long_add(nr, &parent_info->nr_deferred[i]); } } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); } static bool cgroup_reclaim(struct scan_control *sc) @@ -709,9 +709,9 @@ void free_prealloced_shrinker(struct shr shrinker->name = NULL; #endif if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); unregister_memcg_shrinker(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return; } @@ -721,11 +721,11 @@ void free_prealloced_shrinker(struct shr void register_shrinker_prepared(struct shrinker *shrinker) { - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_add_tail_rcu(&shrinker->list, &shrinker_list); shrinker->flags |= SHRINKER_REGISTERED; shrinker_debugfs_add(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); } static int __register_shrinker(struct shrinker *shrinker) @@ -775,13 +775,13 @@ void unregister_shrinker(struct shrinker if (!(shrinker->flags & SHRINKER_REGISTERED)) return; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_del_rcu(&shrinker->list); shrinker->flags &= ~SHRINKER_REGISTERED; if (shrinker->flags & SHRINKER_MEMCG_AWARE) unregister_memcg_shrinker(shrinker); debugfs_entry = shrinker_debugfs_remove(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); _ 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