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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 ED4E2C433E0 for ; Wed, 1 Jul 2020 20:04:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B753620780 for ; Wed, 1 Jul 2020 20:04:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B753620780 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5BD258D005C; Wed, 1 Jul 2020 16:04:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 593328D002B; Wed, 1 Jul 2020 16:04:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 481988D005C; Wed, 1 Jul 2020 16:04:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id 33A728D002B for ; Wed, 1 Jul 2020 16:04:52 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E9ECF8248068 for ; Wed, 1 Jul 2020 20:04:51 +0000 (UTC) X-FDA: 76990585182.10.bone14_59171db26e83 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin10.hostedemail.com (Postfix) with ESMTP id C2EDD16A069 for ; Wed, 1 Jul 2020 20:04:51 +0000 (UTC) X-HE-Tag: bone14_59171db26e83 X-Filterd-Recvd-Size: 3800 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Wed, 1 Jul 2020 20:04:51 +0000 (UTC) IronPort-SDR: ZmZHok+OdeZM62yZxfcH4dZfWSWDqEdsFovvUNhtDu3MBRB95RdcAF2DG+d183riqq8LjIAND1 4BH6SsfzNX3A== X-IronPort-AV: E=McAfee;i="6000,8403,9669"; a="146690024" X-IronPort-AV: E=Sophos;i="5.75,301,1589266800"; d="scan'208";a="146690024" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2020 13:04:49 -0700 IronPort-SDR: KRQVUdiyIf2tJNU3rFxi+VfhbLxczcnP2seiVBRUUfKXHTEoNGmZI4ZV4XvpOSdeui4dCGgtZB qZKQ7qsb8ukw== X-IronPort-AV: E=Sophos;i="5.75,301,1589266800"; d="scan'208";a="481418338" Received: from sadedonx-mobl2.amr.corp.intel.com (HELO intel.com) ([10.252.134.113]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2020 13:04:48 -0700 Date: Wed, 1 Jul 2020 13:04:46 -0700 From: Ben Widawsky To: David Rientjes Cc: Dave Hansen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, 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 Message-ID: <20200701200446.ki5hdgarcpmo2vuf@intel.com> Mail-Followup-To: David Rientjes , Dave Hansen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, 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 References: <20200701152621.D520E62B@viggo.jf.intel.com> <20200701152627.8761147E@viggo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: C2EDD16A069 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 20-07-01 13:03:01, David Rientjes wrote: > 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? > I don't think so because I don't think anything else validates the unused bits remain unused.