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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 842C6C433EF for ; Mon, 15 Nov 2021 08:40:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 207AC60F14 for ; Mon, 15 Nov 2021 08:40:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 207AC60F14 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 C03786B0088; Mon, 15 Nov 2021 03:40:32 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B8AB96B008A; Mon, 15 Nov 2021 03:40:32 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A53686B0092; Mon, 15 Nov 2021 03:40:32 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 9788E6B0088 for ; Mon, 15 Nov 2021 03:40:32 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 49DD58274B for ; Mon, 15 Nov 2021 08:40:32 +0000 (UTC) X-FDA: 78810518094.19.3317EDC Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf17.hostedemail.com (Postfix) with ESMTP id B5CADF000392 for ; Mon, 15 Nov 2021 08:40:31 +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=1636965630; 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=TUIDw/Vuw7+v40VKkRfutNtDggbjfhBkv4VGOk3L19Q=; b=Ci0ZJPGtq0HmK4mWWtSIDRe28Izku4VMV0ywmx5ejPQ0/+6J8WaPTvPV9Iq8Q6rRbIvkpS CW5rh68CNDoxS+T6KRr9B5rSju4KxqS3JXXbHX8lWvjgYiLP1kBqRPYNJ8902q3slrRmpp 7bCABl4gfEqpOtuF9hzzKDc4GWl8gQk= 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 v4 1/3] mm/hwpoison: mf_mutex for soft offline and unpoison Date: Mon, 15 Nov 2021 17:40:04 +0900 Message-Id: <20211115084006.3728254-2-naoya.horiguchi@linux.dev> In-Reply-To: <20211115084006.3728254-1-naoya.horiguchi@linux.dev> References: <20211115084006.3728254-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: B5CADF000392 X-Stat-Signature: b8sgt5qhjmwfk1fxozscpe6onkdj79bu Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Ci0ZJPGt; 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-HE-Tag: 1636965631-100864 Content-Transfer-Encoding: quoted-printable 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_fa= ilure() and soft offline. So apply mf_mutex to soft offline and unpoison. The memory failure handler and soft offline handler get simpler with this= . Signed-off-by: Naoya Horiguchi Reviewed-by: Yang Shi --- ChangeLog v4: - fix type in commit description. 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 pf= n, int flags) lock_page(head); page_flags =3D head->flags; =20 - 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; } =20 +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 =3D 0; unsigned long page_flags; bool retry =3D true; - static DEFINE_MUTEX(mf_mutex); =20 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 =3D p->flags; =20 - /* - * 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 =3D 0; + int ret =3D 0; unsigned long flags =3D 0; static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); @@ -1988,39 +1972,30 @@ int unpoison_memory(unsigned long pfn) p =3D pfn_to_page(pfn); page =3D compound_head(p); =20 + 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; } =20 if (page_count(page) > 1) { unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } =20 if (page_mapped(page)) { unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n", pfn, &unpoison_rs); - return 0; + goto unlock_mutex; } =20 if (page_mapping(page)) { unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#l= x\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; } =20 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; } =20 - 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 =3D 1; } - unlock_page(page); =20 put_page(page); if (freeit && !(pfn =3D=3D my_zero_pfn(0) && page_count(p) =3D=3D 1)) put_page(page); =20 - return 0; +unlock_mutex: + mutex_unlock(&mf_mutex); + return ret; } EXPORT_SYMBOL(unpoison_memory); =20 @@ -2231,9 +2200,12 @@ int soft_offline_page(unsigned long pfn, int flags= ) return -EIO; } =20 + 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; } =20 @@ -2251,5 +2223,7 @@ int soft_offline_page(unsigned long pfn, int flags) } } =20 + mutex_unlock(&mf_mutex); + return ret; } --=20 2.25.1