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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC677C433E0 for ; Wed, 1 Jul 2020 20:03:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8988820760 for ; Wed, 1 Jul 2020 20:03:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="m7ZV4ZqQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726721AbgGAUDF (ORCPT ); Wed, 1 Jul 2020 16:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726049AbgGAUDE (ORCPT ); Wed, 1 Jul 2020 16:03:04 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B648EC08C5C1 for ; Wed, 1 Jul 2020 13:03:04 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id gc9so4904523pjb.2 for ; Wed, 01 Jul 2020 13:03:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=h+1Zhw+IU5Q0TCwvXbDCPP03c9PbqFM6QbL3RKeglzg=; b=m7ZV4ZqQ8dOTQW70jelDPr+AgEtdHXqgtBl2IgnF8daantVBxjfVIMK1Gm8F0Li+oI BxefPgOgTQmCaBj+1lln0RS9uWIH5LCJU7gk7KR2SdjqjdbouPMoV38yKEEhDWStJCD8 txk92EdtNZ31+swmcPZgxROjzV0toLSKWPt0Z/IGgj4fpbAspLLAgqqPeWx8ImLB6gjk b1WYj9qFzqvEkIMskziaG0QSnhRU49ZDaS7Z4Wfeo1H0npKeSez+MuLu9oZKekqHYcZd YUx9TrsSVGTjQYoH8C3lkeRO8GgtA6g+VV4oT4g19iMBZe6OPhKArE84hfJRK8QWZfp2 Fc0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=h+1Zhw+IU5Q0TCwvXbDCPP03c9PbqFM6QbL3RKeglzg=; b=qZL3L0QAdqvAa/t3oMxIMggHxiILzZ87OXrF2BJSE6XAAAG5wtV6R/JxkktdWZ7PWq MTVXR28DI9jTpxkSU9z7qAOKmspOjRnGBGyOFmDAcvHKpqvB0wAjcPRswIGY4M02o5dF Ziq+6lqpLEJLs/u2u/ZuuCl+BHOg80O1f5/wvP7rVirjhDWQsiwTNfEhjwQl5nr2plXK mIIHABw3+8c6aoIrD1zFJ4DIFUxGPrVHM+MPvZURTBlHJyv+oUlR0PWuVw1d2WyRdQdZ KOGvhEoiGePzxku0M8XnkOn0YTde5StGEKCOZJWgo8mOXwvwG30BypYMP3Ic5olPX2bF ZeMQ== X-Gm-Message-State: AOAM530ux0PyhEyK4Z0cfd9PuWSxVEcx0i1Hoq/H2SflqAu51zMww6L2 ZBCWPNUIemXg5RMMmpiGQ9Az/XCfHPY= X-Google-Smtp-Source: ABdhPJwjsX59K7TNEodj6s9VSLwhn8IML/5qqPGnMeNAlqTTpcG08YE/nNMw432H+LegU0Apgf7xPQ== X-Received: by 2002:a17:902:d20c:: with SMTP id t12mr23683155ply.291.1593633783951; Wed, 01 Jul 2020 13:03:03 -0700 (PDT) Received: from [2620:15c:17:3:4a0f:cfff:fe51:6667] ([2620:15c:17:3:4a0f:cfff:fe51:6667]) by smtp.gmail.com with ESMTPSA id oc6sm6464478pjb.43.2020.07.01.13.03.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Jul 2020 13:03:02 -0700 (PDT) Date: Wed, 1 Jul 2020 13:03:01 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Dave Hansen cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, ben.widawsky@intel.com, alex.shi@linux.alibaba.com, dwagner@suse.de, tobin@kernel.org, cl@linux.com, akpm@linux-foundation.org, ying.huang@intel.com, dan.j.williams@intel.com, cai@lca.pw Subject: Re: [PATCH 3/3] mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks In-Reply-To: <20200701152627.8761147E@viggo.jf.intel.com> Message-ID: References: <20200701152621.D520E62B@viggo.jf.intel.com> <20200701152627.8761147E@viggo.jf.intel.com> User-Agent: Alpine 2.23 (DEB 453 2020-06-18) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Jul 2020, Dave Hansen wrote: > diff -puN include/linux/swap.h~mm-vmscan-node_reclaim_mode_helper include/linux/swap.h > --- a/include/linux/swap.h~mm-vmscan-node_reclaim_mode_helper 2020-07-01 08:22:13.650955330 -0700 > +++ b/include/linux/swap.h 2020-07-01 08:22:13.659955330 -0700 > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > > struct notifier_block; > @@ -374,6 +375,12 @@ extern int sysctl_min_slab_ratio; > #define node_reclaim_mode 0 > #endif > > +static inline bool node_reclaim_enabled(void) > +{ > + /* Is any node_reclaim_mode bit set? */ > + return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP); > +} > + > extern void check_move_unevictable_pages(struct pagevec *pvec); > > extern int kswapd_run(int nid); If a user writes a bit that isn't a RECLAIM_* bit to vm.zone_reclaim_mode today, it acts as though RECLAIM_ZONE is enabled: we try to reclaim in zonelist order before falling back to the next zone in the page allocator. The sysctl doesn't enforce any max value :/ I dont know if there is any such user, but this would break them if there is. Should this simply be return !!node_reclaim_mode?