From patchwork Fri Nov 5 05:50:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naoya Horiguchi X-Patchwork-Id: 12604253 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E928C433F5 for ; Fri, 5 Nov 2021 05:52:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 09B8B60FC2 for ; Fri, 5 Nov 2021 05:52:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 09B8B60FC2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 965996B0071; Fri, 5 Nov 2021 01:52:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 914E76B0073; Fri, 5 Nov 2021 01:52:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7E703940007; Fri, 5 Nov 2021 01:52:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0180.hostedemail.com [216.40.44.180]) by kanga.kvack.org (Postfix) with ESMTP id 6E5596B0071 for ; Fri, 5 Nov 2021 01:52:45 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 2E1D91ADAA for ; Fri, 5 Nov 2021 05:52:45 +0000 (UTC) X-FDA: 78773807490.22.C8B5FB9 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf17.hostedemail.com (Postfix) with ESMTP id B7FDCF00039C for ; Fri, 5 Nov 2021 05:52:43 +0000 (UTC) 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=1636091562; 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: in-reply-to:in-reply-to:references:references; bh=6MYrgk1h8uduabtXdyG/GIrSMU16cBLsfGYWNDjMmnM=; b=j6t3YQz1uktOVsvVU4lrNcDiD5tJ4ZFISoVwBjbtu2JaENXBmzWUFKasdlrNBO6ixeC8qg fCtG9FHSIrd2Cr3T+w1OjKJuPlHI6Qz1aoSHl1mO4m1/6JzL34aIEHXNQZaAIp2c5djWq8 tF2+SfM6OZ4MXcokSMD1tLqdr7UFhPs= From: Naoya Horiguchi To: linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , Oscar Salvador , Michal Hocko , Ding Hui , Tony Luck , "Aneesh Kumar K.V" , Miaohe Lin , Yang Shi , Peter Xu , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/3] mm/hwpoison: mf_mutex for soft offline and unpoison Date: Fri, 5 Nov 2021 14:50:56 +0900 Message-Id: <20211105055058.3152564-2-naoya.horiguchi@linux.dev> In-Reply-To: <20211105055058.3152564-1-naoya.horiguchi@linux.dev> References: <20211105055058.3152564-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: naoya.horiguchi@linux.dev Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=j6t3YQz1; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf17.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: B7FDCF00039C X-Stat-Signature: jfywow1b13audpg9dm57xeag7ogx6uty X-HE-Tag: 1636091563-880975 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: Naoya Horiguchi Originally mf_mutex is introduced to serialize multiple MCE events, but it is not that useful to allow unpoison to run in parallel with memory_failure() and soft offline. So apply mf_they to soft offline and unpoison. The memory failure handler and soft offline handler get simpler with this. Signed-off-by: Naoya Horiguchi --- ChangeLog v3: - merge with "mm/hwpoison: remove race consideration" - update description ChangeLog v2: - add mutex_unlock() in "page already poisoned" path in soft_offline_page(). (Thanks to Ding Hui) --- mm/memory-failure.c | 62 +++++++++++++-------------------------------- 1 file changed, 18 insertions(+), 44 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index e8c38e27b753..d29c79de6034 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1507,14 +1507,6 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) lock_page(head); page_flags = head->flags; - if (!PageHWPoison(head)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(head); - put_page(head); - return 0; - } - /* * TODO: hwpoison for pud-sized hugetlb doesn't work right now, so * simply disable it. In order to make it work properly, we need @@ -1628,6 +1620,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, return rc; } +static DEFINE_MUTEX(mf_mutex); + /** * memory_failure - Handle memory failure of a page. * @pfn: Page Number of the corrupted page @@ -1654,7 +1648,6 @@ int memory_failure(unsigned long pfn, int flags) int res = 0; unsigned long page_flags; bool retry = true; - static DEFINE_MUTEX(mf_mutex); if (!sysctl_memory_failure_recovery) panic("Memory failure on page %lx", pfn); @@ -1788,16 +1781,6 @@ int memory_failure(unsigned long pfn, int flags) */ page_flags = p->flags; - /* - * unpoison always clear PG_hwpoison inside page lock - */ - if (!PageHWPoison(p)) { - pr_err("Memory failure: %#lx: just unpoisoned\n", pfn); - num_poisoned_pages_dec(); - unlock_page(p); - put_page(p); - goto unlock_mutex; - } if (hwpoison_filter(p)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -1978,6 +1961,7 @@ int unpoison_memory(unsigned long pfn) struct page *page; struct page *p; int freeit = 0; + int ret = 0; unsigned long flags = 0; static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); @@ -1988,39 +1972,30 @@ int unpoison_memory(unsigned long pfn) p = pfn_to_page(pfn); page = compound_head(p); + mutex_lock(&mf_mutex); + if (!PageHWPoison(p)) { unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } if (page_count(page) > 1) { unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } if (page_mapped(page)) { unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } if (page_mapping(page)) { unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n", pfn, &unpoison_rs); - return 0; - } - - /* - * unpoison_memory() can encounter thp only when the thp is being - * worked by memory_failure() and the page lock is not held yet. - * In such case, we yield to memory_failure() and make unpoison fail. - */ - if (!PageHuge(page) && PageTransHuge(page)) { - unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n", - pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } if (!get_hwpoison_page(p, flags)) { @@ -2028,29 +2003,23 @@ int unpoison_memory(unsigned long pfn) num_poisoned_pages_dec(); unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } - lock_page(page); - /* - * This test is racy because PG_hwpoison is set outside of page lock. - * That's acceptable because that won't trigger kernel panic. Instead, - * the PG_hwpoison page will be caught and isolated on the entrance to - * the free buddy page pool. - */ if (TestClearPageHWPoison(page)) { unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n", pfn, &unpoison_rs); num_poisoned_pages_dec(); freeit = 1; } - unlock_page(page); put_page(page); if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) put_page(page); - return 0; +unlock_mutex: + mutex_unlock(&mf_mutex); + return ret; } EXPORT_SYMBOL(unpoison_memory); @@ -2231,9 +2200,12 @@ int soft_offline_page(unsigned long pfn, int flags) return -EIO; } + mutex_lock(&mf_mutex); + if (PageHWPoison(page)) { pr_info("%s: %#lx page already poisoned\n", __func__, pfn); put_ref_page(ref_page); + mutex_unlock(&mf_mutex); return 0; } @@ -2251,5 +2223,7 @@ int soft_offline_page(unsigned long pfn, int flags) } } + mutex_unlock(&mf_mutex); + return ret; }