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 B9BA3C433EF for ; Mon, 25 Oct 2021 23:06:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A23656105A for ; Mon, 25 Oct 2021 23:06:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235232AbhJYXJH (ORCPT ); Mon, 25 Oct 2021 19:09:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235177AbhJYXI7 (ORCPT ); Mon, 25 Oct 2021 19:08:59 -0400 Received: from out1.migadu.com (out1.migadu.com [IPv6:2001:41d0:2:863f::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D81C8C061243 for ; Mon, 25 Oct 2021 16:06:35 -0700 (PDT) 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 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: naoya.horiguchi@linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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)) -- 2.25.1