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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 409A2C43441 for ; Wed, 14 Nov 2018 08:23:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 11CA4223DD for ; Wed, 14 Nov 2018 08:23:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 11CA4223DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732336AbeKNSZV (ORCPT ); Wed, 14 Nov 2018 13:25:21 -0500 Received: from foss.arm.com ([217.140.101.70]:39688 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730764AbeKNSZV (ORCPT ); Wed, 14 Nov 2018 13:25:21 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D3983EBD; Wed, 14 Nov 2018 00:23:09 -0800 (PST) Received: from [10.162.0.72] (unknown [10.162.0.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 884BF3F5CF; Wed, 14 Nov 2018 00:23:07 -0800 (PST) Subject: Re: [RFC][PATCH v1 11/11] mm: hwpoison: introduce clear_hwpoison_free_buddy_page() To: Naoya Horiguchi Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Michal Hocko , Andrew Morton , Mike Kravetz , "xishi.qiuxishi@alibaba-inc.com" , Laurent Dufour References: <1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1541746035-13408-12-git-send-email-n-horiguchi@ah.jp.nec.com> <20181113001907.GD5945@hori1.linux.bs1.fc.nec.co.jp> From: Anshuman Khandual Message-ID: Date: Wed, 14 Nov 2018 13:53:04 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181113001907.GD5945@hori1.linux.bs1.fc.nec.co.jp> Content-Type: text/plain; charset=iso-2022-jp Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/13/2018 05:49 AM, Naoya Horiguchi wrote: > On Fri, Nov 09, 2018 at 05:03:06PM +0530, Anshuman Khandual wrote: >> >> >> On 11/09/2018 12:17 PM, Naoya Horiguchi wrote: >>> The new function is a reverse operation of set_hwpoison_free_buddy_page() >>> to adjust unpoison_memory() to the new semantics. >>> >>> Signed-off-by: Naoya Horiguchi >> >> snip >> >>> + >>> +/* >>> + * Reverse operation of set_hwpoison_free_buddy_page(), which is expected >>> + * to work only on error pages isolated from buddy allocator. >>> + */ >>> +bool clear_hwpoison_free_buddy_page(struct page *page) >>> +{ >>> + struct zone *zone = page_zone(page); >>> + bool unpoisoned = false; >>> + >>> + spin_lock(&zone->lock); >>> + if (TestClearPageHWPoison(page)) { >>> + unsigned long pfn = page_to_pfn(page); >>> + int migratetype = get_pfnblock_migratetype(page, pfn); >>> + >>> + __free_one_page(page, pfn, zone, 0, migratetype); >>> + unpoisoned = true; >>> + } >>> + spin_unlock(&zone->lock); >>> + return unpoisoned; >>> +} >>> #endif >>> >> >> Though there are multiple page state checks in unpoison_memory() leading >> upto clearing HWPoison flag, the page must not be in buddy already if >> __free_one_page() would be called on it. > > Yes, you're right. > clear_hwpoison_free_buddy_page() is intended to cancel the isolation by > set_hwpoison_free_buddy_page() which removes the target page from buddy allocator, > so the page clear_hwpoison_free_buddy_page() tries to handle is not a buddy page > actually (not linked to any freelist). Got it. Thanks for the explanation.