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 D8A40C6FA99 for ; Tue, 7 Mar 2023 22:26:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231280AbjCGW06 (ORCPT ); Tue, 7 Mar 2023 17:26:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231316AbjCGW0g (ORCPT ); Tue, 7 Mar 2023 17:26:36 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E2CCB0493 for ; Tue, 7 Mar 2023 14:26:04 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9A6A76159D for ; Tue, 7 Mar 2023 22:25:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 029FDC433EF; Tue, 7 Mar 2023 22:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1678227933; bh=rAOfXjF8yybRMHVOo5LsSvLhHO8TTwHDLF2sisrLO+4=; h=Date:To:From:Subject:From; b=bQ37DFw3A1rPxEKmWe9azu/X+fS7itiDfTyC0NzGsiIOUd8Uj9lP3cJYyeht3E7d4 51uEIpGM8jX/gGVUAqfybqMhrqv36/1WKS4Dod+/naGCQoQKNuGSxLaUp3niCCbSqM s2+MZfu66ymgZj0Vls3dyMNzONWY/8Q7NJwzrnm4= Date: Tue, 07 Mar 2023 14:25:32 -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-vmscan-remove-shrinker_rwsem-from-synchronize_shrinkers.patch added to mm-unstable branch Message-Id: <20230307222533.029FDC433EF@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: vmscan: remove shrinker_rwsem from synchronize_shrinkers() has been added to the -mm mm-unstable branch. Its filename is mm-vmscan-remove-shrinker_rwsem-from-synchronize_shrinkers.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-remove-shrinker_rwsem-from-synchronize_shrinkers.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: vmscan: remove shrinker_rwsem from synchronize_shrinkers() Date: Tue, 7 Mar 2023 14:56:04 +0800 Now there are no readers of shrinker_rwsem, so synchronize_shrinkers() does not need to hold the writer of shrinker_rwsem to wait for all running shinkers to complete, synchronize_srcu() is enough. Link: https://lkml.kernel.org/r/20230307065605.58209-8-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 --- mm/vmscan.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/mm/vmscan.c~mm-vmscan-remove-shrinker_rwsem-from-synchronize_shrinkers +++ a/mm/vmscan.c @@ -796,15 +796,11 @@ EXPORT_SYMBOL(unregister_shrinker); /** * synchronize_shrinkers - Wait for all running shrinkers to complete. * - * This is equivalent to calling unregister_shrink() and register_shrinker(), - * but atomically and with less overhead. This is useful to guarantee that all - * shrinker invocations have seen an update, before freeing memory, similar to - * rcu. + * This is useful to guarantee that all shrinker invocations have seen an + * update, before freeing memory. */ void synchronize_shrinkers(void) { - down_write(&shrinker_rwsem); - up_write(&shrinker_rwsem); 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