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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F368C76196 for ; Thu, 23 Mar 2023 15:50:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 963F46B0072; Thu, 23 Mar 2023 11:50:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9155A6B0074; Thu, 23 Mar 2023 11:50:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 78E5E6B0075; Thu, 23 Mar 2023 11:50:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 66D506B0072 for ; Thu, 23 Mar 2023 11:50:45 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 16CA080766 for ; Thu, 23 Mar 2023 15:50:44 +0000 (UTC) X-FDA: 80600600850.09.8DE0338 Received: from mail-qt1-f180.google.com (mail-qt1-f180.google.com [209.85.160.180]) by imf18.hostedemail.com (Postfix) with ESMTP id A37701C0013 for ; Thu, 23 Mar 2023 15:50:42 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=cmpxchg-org.20210112.gappssmtp.com header.s=20210112 header.b=Uax95WAs; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf18.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.160.180 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1679586643; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MgbjNxnbkhKxp3ayTqCe/JjU9SvNsSkqQJ2eCY+DMZI=; b=pV6IgOSkEwZHAoFphr6KMzD0z7IUPBfLdHLRzHXHP1B57D+CwjEjsqkQlpKU83E9o/Hd4j jZ38DwbW9sEhnBpwidNn0NK2NYiRRsxjz7Mp/B3BwSdNaj40TcYBwLbkEm12s/7vO6y/u0 P2LBJfmD6qP42yMvxtWk54uvyQ70r5Y= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=cmpxchg-org.20210112.gappssmtp.com header.s=20210112 header.b=Uax95WAs; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf18.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.160.180 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1679586643; a=rsa-sha256; cv=none; b=Eg96fRIc6DCO+IuoE1ARDxRYInqvxwHocxuQuga+wctyMo5BDIZrlXWxSfzJcKS4s/Y1yV PFT8Q3dAxRhhucEKH4v9yZ3dUvhKKM7eNeirKGlg9H977IXAzGCOgcShrdacfhWN7Aslna mOBW7rve616KHUZAi0Y5JvyJ/m2LV+U= Received: by mail-qt1-f180.google.com with SMTP id w25so4475020qtc.5 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=b+gg0dLXWPTOF9sbIxMn6SS5yKK+GwqBNrEjkLolCvgq3+ZibZUaITUrCvEIYfSexT ETYaG4BfNbATokXN5IQXGFypsBDJqXJnKSY9PMX5I41Y5M/UazQ7cf7PGLe7zBGC9yB9 DgwLnSzEN+gDqsUGpmu0SGwr0ZGJ2CQVf6zDG4Ja0GWAIiJaz5M8cvMLb+tKxWsJl94p gIWDtwU1WxgxziSF4oQ3lYHV9q51vzP1UFiAjnrxOE3AoNNVidoNnhaH5oBLES9uzZG+ CGKRuC3mPeoae82wsqg0pYbT+X/sv01KH2QugAuKtv1gA2Q1+HMy3G/N+GqRt2E/BBPt RkBg== X-Gm-Message-State: AO0yUKX7aV4ZR2DckOQKUUcKwgoELXDtQShSOGS4Cxc12KGrOlk1pyq9 OrOysBi9ZMDpDFrKOVhFXHLYBg== 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> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: A37701C0013 X-Stat-Signature: pgmh9yf4egteng6jjp8yrzyqycdnm1pp X-HE-Tag: 1679586642-737607 X-HE-Meta: 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 X+rx6BjE 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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.