From patchwork Tue Jan 26 00:34:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 12044995 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 283B5C433DB for ; Tue, 26 Jan 2021 00:41:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B0CD221D93 for ; Tue, 26 Jan 2021 00:41:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B0CD221D93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 15C618D0064; Mon, 25 Jan 2021 19:41:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 10B5A8D0059; Mon, 25 Jan 2021 19:41:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0490E8D0064; Mon, 25 Jan 2021 19:41:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0035.hostedemail.com [216.40.44.35]) by kanga.kvack.org (Postfix) with ESMTP id E235B8D0059 for ; Mon, 25 Jan 2021 19:41:39 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A5C49180ACF0D for ; Tue, 26 Jan 2021 00:41:39 +0000 (UTC) X-FDA: 77746073118.19.party93_0716f4d2758a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id 8425A1ACC22 for ; Tue, 26 Jan 2021 00:41:39 +0000 (UTC) X-HE-Tag: party93_0716f4d2758a X-Filterd-Recvd-Size: 4887 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 00:41:38 +0000 (UTC) IronPort-SDR: Sx7IsIzyl6KE+4kW3FJjDfNlZFrsL7RSEqHh8AdFjIRH25qWEU/BqMgOj6FVWuOBA62w8Wx9Ll 3UK7ufyDoJjg== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="264650533" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="264650533" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jan 2021 16:41:37 -0800 IronPort-SDR: Ukmmbnc6CqfXFch4ltMxuPGJw/E8U/45bNuNGTcMcAPr5BRW+9xKntoI90jFmINg3J8IGQc83R bG64GajjAH0w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="429496797" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga001.jf.intel.com with ESMTP; 25 Jan 2021 16:41:37 -0800 Subject: [RFC][PATCH 03/13] mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org,Dave Hansen ,ben.widawsky@intel.com,cl@linux.com,alex.shi@linux.alibaba.com,tobin@kernel.org,akpm@linux-foundation.org,ying.huang@intel.com,dan.j.williams@intel.com,cai@lca.pw,dwagner@suse.de,osalvador@suse.de From: Dave Hansen Date: Mon, 25 Jan 2021 16:34:17 -0800 References: <20210126003411.2AC51464@viggo.jf.intel.com> In-Reply-To: <20210126003411.2AC51464@viggo.jf.intel.com> Message-Id: <20210126003417.72B4BCFB@viggo.jf.intel.com> 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: From: Dave Hansen RECLAIM_ZONE was assumed to be unused because it was never explicitly used in the kernel. However, there were a number of places where it was checked implicitly by checking 'node_reclaim_mode' for a zero value. These zero checks are not great because it is not obvious what a zero mode *means* in the code. Replace them with a helper which makes it more obvious: node_reclaim_enabled(). This helper also provides a handy place to explicitly check the RECLAIM_ZONE bit itself. Check it explicitly there to make it more obvious where the bit can affect behavior. This should have no functional impact. Signed-off-by: Dave Hansen Reviewed-by: Ben Widawsky Acked-by: Christoph Lameter Cc: Alex Shi Cc: "Tobin C. Harding" Cc: Christoph Lameter Cc: Andrew Morton Cc: Huang Ying Cc: Dan Williams Cc: Qian Cai Cc: Daniel Wagner Cc: osalvador Acked-by: David Rientjes Reviewed-by: Oscar Salvador --- Note: This is not cc'd to stable. It does not fix any bugs. --- b/include/linux/swap.h | 7 +++++++ b/mm/khugepaged.c | 2 +- b/mm/page_alloc.c | 2 +- 3 files changed, 9 insertions(+), 2 deletions(-) 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 2021-01-25 16:23:08.330866712 -0800 +++ b/include/linux/swap.h 2021-01-25 16:23:08.339866712 -0800 @@ -12,6 +12,7 @@ #include #include #include +#include #include struct notifier_block; @@ -380,6 +381,12 @@ 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); diff -puN mm/khugepaged.c~mm-vmscan-node_reclaim_mode_helper mm/khugepaged.c --- a/mm/khugepaged.c~mm-vmscan-node_reclaim_mode_helper 2021-01-25 16:23:08.332866712 -0800 +++ b/mm/khugepaged.c 2021-01-25 16:23:08.340866712 -0800 @@ -797,7 +797,7 @@ static bool khugepaged_scan_abort(int ni * If node_reclaim_mode is disabled, then no extra effort is made to * allocate memory locally. */ - if (!node_reclaim_mode) + if (!node_reclaim_enabled()) return false; /* If there is a count for this node already, it must be acceptable */ diff -puN mm/page_alloc.c~mm-vmscan-node_reclaim_mode_helper mm/page_alloc.c --- a/mm/page_alloc.c~mm-vmscan-node_reclaim_mode_helper 2021-01-25 16:23:08.335866712 -0800 +++ b/mm/page_alloc.c 2021-01-25 16:23:08.342866712 -0800 @@ -3875,7 +3875,7 @@ retry: if (alloc_flags & ALLOC_NO_WATERMARKS) goto try_this_zone; - if (node_reclaim_mode == 0 || + if (!node_reclaim_enabled() || !zone_allows_reclaim(ac->preferred_zoneref->zone, zone)) continue;