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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5FC1BD1680C for ; Fri, 9 Jan 2026 10:52:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BDB816B0088; Fri, 9 Jan 2026 05:52:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B89306B0089; Fri, 9 Jan 2026 05:52:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AC3FC6B008A; Fri, 9 Jan 2026 05:52:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 9B8156B0088 for ; Fri, 9 Jan 2026 05:52:16 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id D2A4C1A0445 for ; Fri, 9 Jan 2026 10:52:15 +0000 (UTC) X-FDA: 84312111030.28.EF514EA Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) by imf17.hostedemail.com (Postfix) with ESMTP id 1020B40012 for ; Fri, 9 Jan 2026 10:52:13 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=eZaCSV4R; spf=pass (imf17.hostedemail.com: domain of yajun.deng@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=yajun.deng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767955934; 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-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=1TQfjl1Oyg8oTFGlG7k+ntvES7Gvx/vdSZ107UMkTkk=; b=HBWeAc9tOQ2NWjfuZ8shbjptORVJaJWCZrXhKGOIuBY8Q+iB3NDvnwCBTA6nkoh8MUwwfV Wo0CxRlm0NmEAOFKj9UgXa5CTV2R+hlR4cTkLFNjsUBKd/uLfYJjq1tKOVtCqdkntRbx2T /nr1jE3llP8B6UAlyoa8FvN7aWMg8ZM= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=eZaCSV4R; spf=pass (imf17.hostedemail.com: domain of yajun.deng@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=yajun.deng@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767955934; a=rsa-sha256; cv=none; b=fJ4DFXPAGUwsPtnmFHFcADwLaoYhBdEYc/wr6B7j0bXToj6TWaCoc2uV9YV7FtfUoWbc+j yXsi1XUAMZ7NBVMbuW5t1Qp1eDHpaHC3LQ+w9cvFfMlg9ccBPDxgMoCt/2i5yzaRJ7VSF0 f/U8tUjTbRd6rcs3Gcn46vRcW/H3bC4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1767955931; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=1TQfjl1Oyg8oTFGlG7k+ntvES7Gvx/vdSZ107UMkTkk=; b=eZaCSV4R0Xi5F60N89Kd3yCS91+f00jluNA0tHPTGxReDiNpEL4Hm0eVG95mPaEN4TYduJ ioG4iPz0nUFlMzoGhxoyKORf6+IkyjCi/j9STFNx6Vx2Pg4Hnqi/PLTDqDvfW87c8hAOps e0CtIN2T6e+xF825mbZcFua9+hn/V9E= From: Yajun Deng To: akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yajun Deng Subject: [PATCH] mm/page_alloc: Avoid duplicate NR_FREE_PAGES updates in move_to_free_list() Date: Fri, 9 Jan 2026 18:51:21 +0800 Message-Id: <20260109105121.328780-1-yajun.deng@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: hupoew5z5j9sx8q4qp5t1x9fsyaubmg6 X-Rspamd-Queue-Id: 1020B40012 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1767955933-119858 X-HE-Meta: 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 gYjuyk2/ 8i3J2DCY4F5LPi3gUyC/tH1l1mMmDLYRf3cZUYOMrAEWbDmy6/KllLHc35LDJfw4SPk7MF0JBQxSyahtIjnB3kTrcIthTMbU5lPOE60rr/cOnIepiBUgHZ5nKgfuh01PXUln0KtDm1Vya4ggJbagOEhvNZmFOsSIpAE5iUE5j2qGL/lc28793EzNd5E0MWlcyZBtCXth5FHu0+SdN6+/jBzCcK3PZZeUxGi4Ovof+xWYVmzG+XPQ6Tqcpe4eINrbizAPJhbyaD5q2foB5tFgRUkwXBQ== 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: In move_to_free_list(), when a page block changes its migration type, we need to update free page counts for both the old and new types. Originally, this was done by two calls to account_freepages(), which updates NR_FREE_PAGES and also type-specific counters. However, this causes NR_FREE_PAGES to be updated twice, while the net change is zero in most cases. This patch introduces a new function account_freepages_both() that updates the statistics for both old and new migration types in one go. It avoids the double update of NR_FREE_PAGES by computing the net change only when the isolation status changes. The optimization avoid duplicate NR_FREE_PAGES updates in move_to_free_list(). Signed-off-by: Yajun Deng --- mm/page_alloc.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ebfa07632995..e51d8bd7ab7d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -812,6 +812,16 @@ compaction_capture(struct capture_control *capc, struct page *page, } #endif /* CONFIG_COMPACTION */ +static inline void account_specific_freepages(struct zone *zone, int nr_pages, + int migratetype) +{ + if (is_migrate_cma(migratetype)) + __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, nr_pages); + else if (migratetype == MIGRATE_HIGHATOMIC) + WRITE_ONCE(zone->nr_free_highatomic, + zone->nr_free_highatomic + nr_pages); +} + static inline void account_freepages(struct zone *zone, int nr_pages, int migratetype) { @@ -822,11 +832,25 @@ static inline void account_freepages(struct zone *zone, int nr_pages, __mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages); - if (is_migrate_cma(migratetype)) - __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, nr_pages); - else if (migratetype == MIGRATE_HIGHATOMIC) - WRITE_ONCE(zone->nr_free_highatomic, - zone->nr_free_highatomic + nr_pages); + account_specific_freepages(zone, nr_pages, migratetype); +} + +static inline void account_freepages_both(struct zone *zone, int nr_pages, + int old_mt, int new_mt) +{ + lockdep_assert_held(&zone->lock); + + bool old_isolated = is_migrate_isolate(old_mt); + bool new_isolated = is_migrate_isolate(new_mt); + + if (old_isolated != new_isolated) + __mod_zone_page_state(zone, NR_FREE_PAGES, + old_isolated ? nr_pages : -nr_pages); + + if (!old_isolated) + account_specific_freepages(zone, -nr_pages, old_mt); + if (!new_isolated) + account_specific_freepages(zone, nr_pages, new_mt); } /* Used for pages not on another list */ @@ -869,8 +893,7 @@ static inline void move_to_free_list(struct page *page, struct zone *zone, list_move_tail(&page->buddy_list, &area->free_list[new_mt]); - account_freepages(zone, -nr_pages, old_mt); - account_freepages(zone, nr_pages, new_mt); + account_freepages_both(zone, nr_pages, old_mt, new_mt); if (order >= pageblock_order && is_migrate_isolate(old_mt) != is_migrate_isolate(new_mt)) { -- 2.34.1