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 D0991C64EC4 for ; Thu, 9 Mar 2023 09:40:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231281AbjCIJke (ORCPT ); Thu, 9 Mar 2023 04:40:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231270AbjCIJk3 (ORCPT ); Thu, 9 Mar 2023 04:40:29 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81C08E824F for ; Thu, 9 Mar 2023 01:40:27 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0F46421D96; Thu, 9 Mar 2023 09:40:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1678354826; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SvWQ2PVUQBGEt3Okq0OQm74K/a9Nj1kICx/Tp01CsfY=; b=m1ybD+sgyfl5MzrJqgQzJ74iON6UP1Qx4LCdBgakX8JVqAMnDblmYq3cWLn5Z79rheuMqN aYGbP8F2BX/x9mxdPLnM5cwx1yBIAB02tWwWt7phkOlOlOs1GnAzyw2hs4KreDmI0x1a20 afell2zym3CtJsOdTRU4l3Q1QHDDKGc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1678354826; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SvWQ2PVUQBGEt3Okq0OQm74K/a9Nj1kICx/Tp01CsfY=; b=IT/oiJ0OhkIkm7P+/XKsXrvaWEJc/2UnwwHuSZiwg8TbV30vfBHvqWP7ZmzqVNWxe06kTj gdT++hRwFNJkS0Dw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id C7A921391B; Thu, 9 Mar 2023 09:40:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id K6cYMImpCWQVFQAAMHmgww (envelope-from ); Thu, 09 Mar 2023 09:40:25 +0000 Message-ID: <80d8df29-8077-9de7-c304-9029375fc877@suse.cz> Date: Thu, 9 Mar 2023 10:40:25 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH v4 7/8] mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers() Content-Language: en-US To: Qi Zheng , 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, rppt@kernel.org 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 References: <20230307065605.58209-1-zhengqi.arch@bytedance.com> <20230307065605.58209-8-zhengqi.arch@bytedance.com> From: Vlastimil Babka In-Reply-To: <20230307065605.58209-8-zhengqi.arch@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/7/23 07:56, Qi Zheng wrote: > 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. > > Signed-off-by: Qi Zheng Acked-by: Vlastimil Babka > --- > mm/vmscan.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 7aaf6f94ac1b..ac7ab4aa344f 100644 > --- a/mm/vmscan.c > +++ b/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); > }