From patchwork Mon Oct 25 23:05:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naoya Horiguchi X-Patchwork-Id: 12583465 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 40C52C433EF for ; Mon, 25 Oct 2021 23:06:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E955561073 for ; Mon, 25 Oct 2021 23:06:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E955561073 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 87CF480009; Mon, 25 Oct 2021 19:06:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 82B1A940007; Mon, 25 Oct 2021 19:06:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6CCA880009; Mon, 25 Oct 2021 19:06:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0121.hostedemail.com [216.40.44.121]) by kanga.kvack.org (Postfix) with ESMTP id 5A41F940007 for ; Mon, 25 Oct 2021 19:06:36 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 09F678249980 for ; Mon, 25 Oct 2021 23:06:36 +0000 (UTC) X-FDA: 78736495992.08.B3C6A7A Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by imf21.hostedemail.com (Postfix) with ESMTP id AD928D0425FE for ; Mon, 25 Oct 2021 23:06:32 +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=1635203194; 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=jOfu9yayDhzvLAsYLRzMlhcWXOr3HMUMOxXzk71LJi4=; b=JKBY3MYo8v0gSQav25vpBtSiuxqoEwKJxKTWGqMLui4F+75+cQQNtI180Ey1Qr7LdBNVS5 p/eaMrrkla/PTz6zj2sHXRZVgy43DZoFbB5I+WYQDtkHNmjW3EGc5jaZfX8gw2QKr1LB1s NOZzRsppZTWxKU76PalPJRmFIZUeb7U= 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 v2 2/4] mm/hwpoison: remove race consideration Date: Tue, 26 Oct 2021 08:05:01 +0900 Message-Id: <20211025230503.2650970-3-naoya.horiguchi@linux.dev> In-Reply-To: <20211025230503.2650970-1-naoya.horiguchi@linux.dev> References: <20211025230503.2650970-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: naoya.horiguchi@linux.dev X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: AD928D0425FE X-Stat-Signature: tcp93utt9yojzttser5xqgffkx7q3a34 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=JKBY3MYo; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf21.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev X-HE-Tag: 1635203192-888257 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 Now memory_failure() and unpoison_memory() are protected by mf_mutex, so no need to explicitly check races between them. So remove them. Signed-off-by: Naoya Horiguchi --- mm/memory-failure.c | 37 ------------------------------------- 1 file changed, 37 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 97297edfbd8e..a47b741ca04b 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 @@ -1789,16 +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(); @@ -2016,17 +1998,6 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } - /* - * 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); - goto unlock_mutex; - } - if (!get_hwpoison_page(p, flags)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); @@ -2035,20 +2006,12 @@ int unpoison_memory(unsigned long pfn) 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))