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 44F1EC4332F for ; Wed, 23 Nov 2022 15:45:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 912156B0071; Wed, 23 Nov 2022 10:45:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8C1C36B0073; Wed, 23 Nov 2022 10:45:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B01D6B0074; Wed, 23 Nov 2022 10:45:07 -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 6EB336B0071 for ; Wed, 23 Nov 2022 10:45:07 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 4307E1C6AB7 for ; Wed, 23 Nov 2022 15:45:07 +0000 (UTC) X-FDA: 80165130654.11.498FA78 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf20.hostedemail.com (Postfix) with ESMTP id 63CFC1C000E for ; Wed, 23 Nov 2022 15:45:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=6eE8Qd8mDLx/Y2cYwBF7qMn+RB+S43WwvbsxuHk7jug=; b=imMVHw6Nv6x+ZbwXlZ2FtbyM8z 9d1b/hnNt1/QMW4GgWyBgJ+jhWZ8VZGH3JRm0y59UZDWcjG0FV+7PNHibFOHcQM5MAW6sSgcAugAx vN9C8mCgNWXFFXeNOGVaBUVZyk1S4WL1ZIqMWIil8IB7fSWTtHIGWZyvps1XDLB+WiE6gI18ql7KD 4+vGPhPeDhbf25iSgRiPLEUxerz2FlVjNnF8i6vN2/ft6eIYtdgbIcmXdS4kd6TsN+iZMYiGvfUHe FSQ1y7hjXlg/++rof3FluywZsuSJVvtlzpyNFbZ3FeudRpNXQgVg9nb9D9HNe31r0r0QZ/Kt0qB94 +Dn8TcCQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxrvt-007m3D-VQ; Wed, 23 Nov 2022 15:45:06 +0000 Date: Wed, 23 Nov 2022 15:45:05 +0000 From: Matthew Wilcox To: wonder_rock@126.com Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] mm/page_alloc: merge two get_pfnblock_migratetype() into one Message-ID: References: <20221123134043.33896-1-wonder_rock@126.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221123134043.33896-1-wonder_rock@126.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669218306; a=rsa-sha256; cv=none; b=eP9En9u1tGWEttmOKBu/au4KTJhyKlz2Lriz7FXWNFDFH4uRINnP5exwfKJWbvC7ffivxU RAAioust75QO5ojluSHdrfrA2rgeyOekaDA4aC/wNZxx+s0XXG6lojyuheriTjVYqu50IU yZ5IXF1h42S6iBEFIKfGSIxFuxjOhbM= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=imMVHw6N; spf=none (imf20.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669218306; 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=6eE8Qd8mDLx/Y2cYwBF7qMn+RB+S43WwvbsxuHk7jug=; b=UgGlnZohyg5vdxqlQJ/V0VeAJHo0Uz8d0gjKTl8Z5eBX6/eS4A7Qd+kUVxGm7lwW3oCCbh LCN8L7Wfg2Q7lkBbdVCWtYrHNTxvsPwSqARyADRSsqUqVE1WDUnpyq0nJy2Vb0ZO5PbH2L VX2xymqe2rQ7zysocjxJ4/DJRyH9ybw= X-Stat-Signature: t4cjpc3msqiwzy6skrr76bdqambi3ia5 X-Rspamd-Queue-Id: 63CFC1C000E X-Rspam-User: Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=imMVHw6N; spf=none (imf20.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam02 X-HE-Tag: 1669218305-787720 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 Wed, Nov 23, 2022 at 09:40:43PM +0800, wonder_rock@126.com wrote: > From: Deyan Wang > > It is safe to get_pfnblock_migratetype() in critical section, > so just call get_pfnblock_migratetype() once. No, you don't understand. zone->lock is HOT and we want to avoid calling get_pfnblock_migratetype() under the lock, if we can avoid it. Which we usually can. > Signed-off-by: Deyan Wang > --- > mm/page_alloc.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 6652df1f5cc8..c7ba9d65d1c0 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1704,13 +1704,8 @@ static void __free_pages_ok(struct page *page, unsigned int order, > if (!free_pages_prepare(page, order, true, fpi_flags)) > return; > > - migratetype = get_pfnblock_migratetype(page, pfn); > - > spin_lock_irqsave(&zone->lock, flags); > - if (unlikely(has_isolate_pageblock(zone) || > - is_migrate_isolate(migratetype))) { > - migratetype = get_pfnblock_migratetype(page, pfn); > - } > + migratetype = get_pfnblock_migratetype(page, pfn); > __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); > spin_unlock_irqrestore(&zone->lock, flags); > > -- > 2.25.1 > >