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 B417CC3DA6E for ; Wed, 3 Jan 2024 18:20:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 44A936B03BB; Wed, 3 Jan 2024 13:20:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3FBED6B03BC; Wed, 3 Jan 2024 13:20:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C33D6B03BD; Wed, 3 Jan 2024 13:20:05 -0500 (EST) 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 1B2656B03BB for ; Wed, 3 Jan 2024 13:20:05 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id AABE8403C3 for ; Wed, 3 Jan 2024 18:20:04 +0000 (UTC) X-FDA: 81638813928.09.C79DB9B Received: from mail-qt1-f176.google.com (mail-qt1-f176.google.com [209.85.160.176]) by imf24.hostedemail.com (Postfix) with ESMTP id B7F83180009 for ; Wed, 3 Jan 2024 18:20:02 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=bC9q5eXk; spf=pass (imf24.hostedemail.com: domain of schatzberg.dan@gmail.com designates 209.85.160.176 as permitted sender) smtp.mailfrom=schatzberg.dan@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1704306002; 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=OrPWR9HpDsfok0xoAtga3b/s4MSroYmZsQH3rRBi6PI=; b=fofRW/1xD8CdlrjBvHhT5Um3LRpf+dfLKSaEzbmXZlMASCsTWZsIGTSS2bZ0ul8i0zRQnt sBpPkrjVeDxvpsmLPADnB8eG5AUZb/uTBqVS8Lj2KwtpxyERo82XfkFVa6879sj82mgWHL zXgHhdk/BZXpspm8dV4YSKMsGhbIwsw= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=bC9q5eXk; spf=pass (imf24.hostedemail.com: domain of schatzberg.dan@gmail.com designates 209.85.160.176 as permitted sender) smtp.mailfrom=schatzberg.dan@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1704306002; a=rsa-sha256; cv=none; b=k4sS7mZ12kOKjv7btBiNKguIk+RBHSLtiTw9HEHkO0usXVVu7fJqmEj2a1UlMbjBjq15k/ 0WdRr8tMiMbOG2ZTKQJhUj12BxFL7sNy1O8URje9Ec9aivoOYEo5jim8FxsWgJBegjcKAw QRi8/RypXqRBaCNiAOrOLHiCIqTxXlU= Received: by mail-qt1-f176.google.com with SMTP id d75a77b69052e-427b8775aebso5266441cf.1 for ; Wed, 03 Jan 2024 10:20:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704306002; x=1704910802; darn=kvack.org; 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=OrPWR9HpDsfok0xoAtga3b/s4MSroYmZsQH3rRBi6PI=; b=bC9q5eXk/VlBoQKBvWCOpp/Em2QLw/dyd+NQUTbWnSYSt3oaKngdRyRCMC9y/pc9TH U+TJY4e6sKzo5fRgPl1kWcSLaxwWha+QhgeQkDlnabxadq7To5puajOXS2mNPMUxUxA1 s9JsIbDAFQ69d4RLjtcxzz+7YuweBVgG85zbL1IVnvL+tmhr3TtVQVNZavc9W11zdsXQ W0CNuA/z/Zfg6fUmIu3bQOzmWMOJMEyufgF5JXpzlQZecHdMLwtdZeKmJz/kAQFXy+Np lVXxsv3frVW5I0ycOfxsWPM1mkY+2Gqinh1bws3bPtPf+wLko4sNoIN2k88r4AuHbzwE 1JmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704306002; x=1704910802; 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=OrPWR9HpDsfok0xoAtga3b/s4MSroYmZsQH3rRBi6PI=; b=gpWUPO45TFeP3E3/YGqcWtsrM3YZWK+Eru6hecmNND0hHmyqdsRr9yYGWixrDQgncZ K4j+JsO4UO5NEieyO229MD92kRtEhebTv7tm07VQVYqdjuRKiRFOJwUnMF03s7suoIi6 x5QKFisCefr6EOsBeZhsrNMeXbCEENFvRwNOzFXe3+MjinuK9N3Scl4dsisNweR5YM/H OxEU6JrIKLIyhC+w28TKJd2bPkXnjH83oj77sz4MezRlziS/MEM0mT1HxJnRS/0eUQ8A vomTCUN7hYuL1kqxz4JuAEpJt2nfWUsmLHnTYzqbUOwgGTXpHskuMb17+Pzdv6z1Ox5a m10Q== X-Gm-Message-State: AOJu0Ywf0/9iZOSYW4n6U1azsQHl7rUZJcJktgRj9Ld1doYw3K84CvMn Qm837PCWTH8C1NvmVmBFzx0= X-Google-Smtp-Source: AGHT+IEznFViHNZVbxOOUJA44LzQJGRsagsfg2qaFqollE3lXewLiQHeCmTuv7TaYn0hcrP/qHy6Sw== X-Received: by 2002:a05:622a:34b:b0:428:3018:89b0 with SMTP id r11-20020a05622a034b00b00428301889b0mr1818061qtw.35.1704306001635; Wed, 03 Jan 2024 10:20:01 -0800 (PST) Received: from dschatzberg-fedora-PC0Y6AEN ([2620:10d:c091:400::5:fcab]) by smtp.gmail.com with ESMTPSA id cg13-20020a05622a408d00b0042831b379c7sm1734711qtb.89.2024.01.03.10.20.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Jan 2024 10:20:01 -0800 (PST) Date: Wed, 3 Jan 2024 13:19:59 -0500 From: Dan Schatzberg To: Yu Zhao Cc: Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed , Michal Hocko , David Rientjes , Chris Li , Tejun Heo , Zefan Li , Johannes Weiner , Jonathan Corbet , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , David Hildenbrand , Matthew Wilcox , Kefeng Wang , Yue Zhao , Hugh Dickins Subject: Re: [PATCH v6 2/2] mm: add swapiness= arg to memory.reclaim Message-ID: References: <20240103164841.2800183-1-schatzberg.dan@gmail.com> <20240103164841.2800183-3-schatzberg.dan@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: B7F83180009 X-Rspam-User: X-Stat-Signature: 8fmar9qtcy63nmt8zfgzydcwm7defsz3 X-Rspamd-Server: rspam01 X-HE-Tag: 1704306002-156069 X-HE-Meta: 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 QI1ngd4G 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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: List-Subscribe: List-Unsubscribe: On Wed, Jan 03, 2024 at 10:19:40AM -0700, Yu Zhao wrote: [...] > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index d91963e2d47f..394e0dd46b2e 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -92,6 +92,11 @@ struct scan_control { > > unsigned long anon_cost; > > unsigned long file_cost; > > > > +#ifdef CONFIG_MEMCG > > + /* Swappiness value for proactive reclaim. Always use sc_swappiness()! */ > > + int *proactive_swappiness; > > +#endif > > Why is proactive_swappiness still a pointer? The whole point of the > previous conversation is that sc->proactive can tell whether > sc->swappiness is valid or not, and that's less awkward than using a > pointer. It's the same reason as before - zero initialization ensures that the pointer is NULL which tells us if it's valid or not. Proactive reclaim might not set swappiness and you need to distinguish swappiness of 0 and not-set. See this discussion with Michal: https://lore.kernel.org/linux-mm/ZZUizpTWOt3gNeqR@tiehlicka/ > Also why the #ifdef here? I don't see the point for a small stack > variable. Otherwise wouldn't we want to do this for sc->proactive as > well? This was Michal's request and it feels similar to your rationale for naming it proactive_swappiness - it's just restricting the interface down to the only use-cases. I'd be fine with doing the same in sc->proactive as a subsequent patch. See https://lore.kernel.org/linux-mm/ZZUhBoTNgL3AUK3f@tiehlicka/