From patchwork Fri Jan 31 06:14:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11359249 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 58805139A for ; Fri, 31 Jan 2020 06:14:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 24D7B20663 for ; Fri, 31 Jan 2020 06:14:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="19l+g9Ru" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24D7B20663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 65A476B0539; Fri, 31 Jan 2020 01:14:34 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 4AA516B053B; Fri, 31 Jan 2020 01:14:34 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 39A986B053C; Fri, 31 Jan 2020 01:14:34 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0174.hostedemail.com [216.40.44.174]) by kanga.kvack.org (Postfix) with ESMTP id 177C56B0539 for ; Fri, 31 Jan 2020 01:14:34 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id C47634DB4 for ; Fri, 31 Jan 2020 06:14:33 +0000 (UTC) X-FDA: 76436915226.13.clock60_27cb7e5548310 X-Spam-Summary: 2,0,0,1ffb0765defaff36,d41d8cd98f00b204,akpm@linux-foundation.org,:akpm@linux-foundation.org:kirill.shutemov@linux.intel.com::mm-commits@vger.kernel.org:richardw.yang@linux.intel.com:torvalds@linux-foundation.org,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1534:1542:1711:1730:1747:1777:1792:2393:2525:2559:2563:2682:2685:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3353:3865:3866:3867:3868:3870:3871:3872:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:5007:6261:6653:7576:8599:8957:9025:9545:10004:10913:11026:11232:11473:11658:11914:12043:12048:12296:12297:12438:12517:12519:12555:12679:12783:12986:13095:14096:14181:14721:14849:21080:21433:21451:21627:21939:21990:30054:30070,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-62.2.0.100 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtim e:30,LUA X-HE-Tag: clock60_27cb7e5548310 X-Filterd-Recvd-Size: 4072 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Fri, 31 Jan 2020 06:14:33 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 98AE82082E; Fri, 31 Jan 2020 06:14:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580451272; bh=QU5mo8w9uNQ6S/WkZY9PNbwrdZ2/onUxk+49kZyDu/M=; h=Date:From:To:Subject:In-Reply-To:From; b=19l+g9Rue9c2WgdP7QpA0vZgjyu9TwpgxUA1gHOya1uJo7DSkJcKXIY0Qn0ZlTNt7 mJmx1jLsbMxPtr474cstmcZcGaugUjd7/aOaxlCx4bKS7QFrWJBXO44vRSEku0p1Oz FaoDX92wHOIVOIj+aMgUMHBOak5utsxRK5i0U2n8= Date: Thu, 30 Jan 2020 22:14:32 -0800 From: Andrew Morton To: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, richardw.yang@linux.intel.com, torvalds@linux-foundation.org Subject: [patch 063/118] mm/huge_memory.c: use head to emphasize the purpose of page Message-ID: <20200131061432.4ZNoGHb19%akpm@linux-foundation.org> In-Reply-To: <20200130221021.5f0211c56346d5485af07923@linux-foundation.org> User-Agent: s-nail v14.8.16 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: Wei Yang Subject: mm/huge_memory.c: use head to emphasize the purpose of page During split huge page, it checks the property of the page. Currently we do the check on page and head without emphasizing the check is on the compound page. In case the page passed to split_huge_page_to_list is a tail page, audience would take some time to think about whether the check is on compound page or tail page itself. To make it explicit, use head instead of page for those checks. After this, audience would be more clear about the checks are on compound page and the page is used to do the split and dump error message if failed. Link: http://lkml.kernel.org/r/20200110032610.26499-2-richardw.yang@linux.intel.com Signed-off-by: Wei Yang Acked-by: Kirill A. Shutemov Signed-off-by: Andrew Morton --- mm/huge_memory.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- a/mm/huge_memory.c~mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page +++ a/mm/huge_memory.c @@ -2704,7 +2704,7 @@ int split_huge_page_to_list(struct page { struct page *head = compound_head(page); struct pglist_data *pgdata = NODE_DATA(page_to_nid(head)); - struct deferred_split *ds_queue = get_deferred_split_queue(page); + struct deferred_split *ds_queue = get_deferred_split_queue(head); struct anon_vma *anon_vma = NULL; struct address_space *mapping = NULL; int count, mapcount, extra_pins, ret; @@ -2713,10 +2713,10 @@ int split_huge_page_to_list(struct page pgoff_t end; VM_BUG_ON_PAGE(is_huge_zero_page(head), head); - VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(!PageCompound(page), page); + VM_BUG_ON_PAGE(!PageLocked(head), head); + VM_BUG_ON_PAGE(!PageCompound(head), head); - if (PageWriteback(page)) + if (PageWriteback(head)) return -EBUSY; if (PageAnon(head)) { @@ -2767,7 +2767,7 @@ int split_huge_page_to_list(struct page goto out_unlock; } - mlocked = PageMlocked(page); + mlocked = PageMlocked(head); unmap_page(head); VM_BUG_ON_PAGE(compound_mapcount(head), head); @@ -2800,10 +2800,10 @@ int split_huge_page_to_list(struct page list_del(page_deferred_list(head)); } if (mapping) { - if (PageSwapBacked(page)) - __dec_node_page_state(page, NR_SHMEM_THPS); + if (PageSwapBacked(head)) + __dec_node_page_state(head, NR_SHMEM_THPS); else - __dec_node_page_state(page, NR_FILE_THPS); + __dec_node_page_state(head, NR_FILE_THPS); } spin_unlock(&ds_queue->split_queue_lock);