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 597B9C77B61 for ; Thu, 23 Mar 2023 15:50:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232019AbjCWPur (ORCPT ); Thu, 23 Mar 2023 11:50:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231974AbjCWPuo (ORCPT ); Thu, 23 Mar 2023 11:50:44 -0400 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [IPv6:2607:f8b0:4864:20::82d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A32F1BFC for ; Thu, 23 Mar 2023 08:50:42 -0700 (PDT) Received: by mail-qt1-x82d.google.com with SMTP id c19so27059570qtn.13 for ; Thu, 23 Mar 2023 08:50:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20210112.gappssmtp.com; s=20210112; t=1679586641; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=MgbjNxnbkhKxp3ayTqCe/JjU9SvNsSkqQJ2eCY+DMZI=; b=Uax95WAssNXE3MIDqKKB3u/nqAPCZSxTVSddkIH48B1KHmuIotqFwdvX5KENELaT+e srIzL8LklW2Ssqy1T23s3P4A7Rbrwc7/2yIjR9CSxZFKptYFPEBvPh7JwY7gaMOp6w9N FojxMBtSySjPkBprMQil3VsaB32A1a94++3AgzvX44rNqNkl9uduUufYh1DyMwtlafgk 0nO9yh1udd1cAqnMBwDvHsl7/slURj+lRn5rIZtNHBwsOQfAB+bjCzuke3CE1Sje0C5q +vS4rnZ/lpITkAcIgL5Cs5+LDhdOP+yzSSHCyKfUF8EepIy2Cfeo4UXGo9FZbR6oDODF 5qKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679586641; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=MgbjNxnbkhKxp3ayTqCe/JjU9SvNsSkqQJ2eCY+DMZI=; b=m7qfPW2VX0XvSVjQv05Ax25Zb24DIRwD5AabyKnypc7FU5a8va/Wbd4UlpRXFeDH/5 4Y+gmx4/X5nhQ/3Vzi/yJ4F0yTQwhuihccBj19ZIHfgN+Zx+a7ae9UxjB92JaXFvjUCX DdsLu8+tsz1bD0IRoeIqQD5qQm7lJob6OFgj8HUjP7dmC84gA0MCjOmicWVQmMacjXY1 SqTaot72UTqaqFIKJN5peMFA+E8sR3J0rtzTgoA76Mwim3nf49qS3TXQPScrBVxcM0bQ GL5Auq7q878qj9892rbEw0OwiAjGo6cw5NkUmr+L9zDjFc5jtEMA+RZJy6jpBqqC1xBk tlDg== X-Gm-Message-State: AO0yUKVBcxL/eDpLv2qsQqk/EJaqSDoVwAcFkbXGq+bpBVVocx83bPBQ tv/VASctjFK/r6G/E/3+/hARPA== X-Google-Smtp-Source: AK7set+/zJMyNiSMTKDzy3E2l/DM0mRht23TAL9P5RJkKER4z4Xh6WDwUYLoOR1VqnmcxtaT9g602Q== X-Received: by 2002:a05:622a:1893:b0:3e3:913c:1c9c with SMTP id v19-20020a05622a189300b003e3913c1c9cmr5154867qtc.1.1679586641731; Thu, 23 Mar 2023 08:50:41 -0700 (PDT) Received: from localhost ([2620:10d:c091:400::5:62db]) by smtp.gmail.com with ESMTPSA id i22-20020ac860d6000000b003dd8ad765dcsm7142374qtm.76.2023.03.23.08.50.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Mar 2023 08:50:41 -0700 (PDT) Date: Thu, 23 Mar 2023 11:50:40 -0400 From: Johannes Weiner To: Yosry Ahmed Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org Subject: Re: [RFC PATCH 6/7] workingset: memcg: sleep when flushing stats in workingset_refault() Message-ID: <20230323155040.GB739026@cmpxchg.org> References: <20230323040037.2389095-1-yosryahmed@google.com> <20230323040037.2389095-7-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230323040037.2389095-7-yosryahmed@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 23, 2023 at 04:00:36AM +0000, Yosry Ahmed wrote: > In workingset_refault(), we call mem_cgroup_flush_stats_delayed() to > flush stats within an RCU read section and with sleeping disallowed. > Move the call to mem_cgroup_flush_stats_delayed() above the RCU read > section and allow sleeping to avoid unnecessarily performing a lot of > work without sleeping. > > Signed-off-by: Yosry Ahmed > --- > > A lot of code paths call into workingset_refault(), so I am not > generally sure at all whether it's okay to sleep in all contexts or not. > Feedback here would be very helpful. Yes, it's safe.