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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9886CC433F5 for ; Wed, 29 Sep 2021 08:06:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C1C5613D0 for ; Wed, 29 Sep 2021 08:06:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244563AbhI2III (ORCPT ); Wed, 29 Sep 2021 04:08:08 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:46450 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244540AbhI2IIF (ORCPT ); Wed, 29 Sep 2021 04:08:05 -0400 Received: from relay1.suse.de (relay1.suse.de [149.44.160.133]) by smtp-out1.suse.de (Postfix) with ESMTP id 79107223AA; Wed, 29 Sep 2021 08:06:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1632902784; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TSI5m2XtJxwQsHbZ7fT2hgL1JimUqhFMlSOa0hMeAqE=; b=nQ3zyjNRAQHSP7HZvghcO8YhihnkTugPkyO4+m1D1AtVucXIcbIn85IkBuMPrCbZ1Zla1K hcrft2nq4jFNhlnTX2AYvua+B3k5AGCOoHBP48VjH6uMHEyXMiUO79tiANKXW9eROrUGZw p+7+r9TLr8JQA4tFm8gjL1iTgzkAjWQ= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay1.suse.de (Postfix) with ESMTPS id 45AAC25D50; Wed, 29 Sep 2021 08:06:24 +0000 (UTC) Date: Wed, 29 Sep 2021 10:06:23 +0200 From: Michal Hocko To: Sultan Alsawaf Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: vmscan: Replace shrinker_rwsem trylocks with SRCU protection Message-ID: References: <20210927074823.5825-1-sultan@kerneltoast.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 27-09-21 09:53:59, Sultan Alsawaf wrote: > On Mon, Sep 27, 2021 at 10:36:36AM +0200, Michal Hocko wrote: > > Can you be more specific about those scenarios please? > > I see frequent tmpfs mounts/unmounts in Android which result in lots of > superblocks being created and destroyed, and each superblock has its own > shrinker. This is an important detail to mention in the changelog. Including some details about the scale of the problem. > > I have a vague recollection that this approach has been proposed in the > > past. Have you checked previous attempts? > > I wasn't aware that there were previous attempts. Is this [1] the previous > attempt you're thinking of? It seems like the thread just died out. Was the main > gripe that always enabling CONFIG_SRCU increased the kernel's size too much when > tinyfication was desired? There were more discussions. I have also found https://lore.kernel.org/lkml/1510609063-3327-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp My memory is quite dim and I do not have time to re-read those discussions again right now. But if I remember correctly the last one has died out because a deeper evaluation between the SRCU and rw semaphores was required. > Sultan > > [1] https://lore.kernel.org/all/153365347929.19074.12509495712735843805.stgit@localhost.localdomain/ -- Michal Hocko SUSE Labs