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 B4F8BC433F5 for ; Wed, 27 Oct 2021 01:32:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5551861040 for ; Wed, 27 Oct 2021 01:32:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5551861040 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id ECBC780007; Tue, 26 Oct 2021 21:32:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E53A5940007; Tue, 26 Oct 2021 21:32:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D1B9780007; Tue, 26 Oct 2021 21:32:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0116.hostedemail.com [216.40.44.116]) by kanga.kvack.org (Postfix) with ESMTP id C2A7E940007 for ; Tue, 26 Oct 2021 21:32:49 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 7F92A39F48 for ; Wed, 27 Oct 2021 01:32:49 +0000 (UTC) X-FDA: 78740493258.02.5F75876 Received: from mail-ed1-f52.google.com (mail-ed1-f52.google.com [209.85.208.52]) by imf08.hostedemail.com (Postfix) with ESMTP id 28C133000251 for ; Wed, 27 Oct 2021 01:32:42 +0000 (UTC) Received: by mail-ed1-f52.google.com with SMTP id g8so3953404edb.2 for ; Tue, 26 Oct 2021 18:32:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=AiF02oyJyNSKjjF+SviMCoaPH4YrjeDtKStxXgTA/Os=; b=En4HPJgUIBhmzDo9CavHXJFsU8XXcMsoXq3yWDDfXIsQdDkSgPZ/wNYvgu5gEhtUQB ffyvSfopGGxj2ZoGNwHgQLgFPVpntbj/W1DZl0kw4QsSan1LxR/ozm3e7VUK89mygkZf qmh/ggU48k2WREFkXjGMU8s4D+WcIRrYYvpG2c3E8lV5D4CK+r8wfpd9p1RC1fymtwTo 8BYianIrddXZ4uHp5bFRU+RwUQIl3szeXvz5OFvd/Vj36RISKx1vgsHVVZhOkXVG6YQ3 Dez8Yb6A6pu6hakHf8CRoCGD5rBeMpeH3Q102ri5c3IRoFWzpSfVau8XhJOy3VkB777h F29A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=AiF02oyJyNSKjjF+SviMCoaPH4YrjeDtKStxXgTA/Os=; b=xCY/iTaIV5wn3gFBEQvCQrrb9r5T702qVar6MtH2isbluKx4NYEuZiAQ8A3k+GrJFq NVHlUYbOrmoyWs8xa7YyMKw5cteAqJq2sP8nCOHOR/S76ng054YRyjjLGWyIEIpq0PXF xaDpElnHQbhq8V78cqcQ2JyLLJG9yQh3WfNUCueejdZte+Yf95Vpb1+9sxtjR7ziQnKv HvRthsauKiKYby+wRLl4DMDbidQTqzjlU/Sx82Zf4sSoEthLnQvCeNHaGvGZ0fDBMgQG rcuE2S6Lvn/EwlAgHLrGgWL/Q63rZziCUE6xRbQ6yFYiYfy6PU/uOugejBiUGWBjwldc BsOw== X-Gm-Message-State: AOAM530hjpTVjU4Tmcw2MOJ07WxR0RQ1kZuqa0rb+T/v1b9/FsX22Wem Ms+mj1tuuUymOaaEWoYPRguGmbD6MUA7uGvf8j8= X-Google-Smtp-Source: ABdhPJxnzJSIHBNIPi5OmZ/qi1DLwq4Vbq4+QCpleUGhYj5NcrO8iMsXgSxYodLnXz9Z9dxZW2HCVcZ+yQZ6QgVZsbo= X-Received: by 2002:aa7:cf96:: with SMTP id z22mr30422393edx.81.1635298368017; Tue, 26 Oct 2021 18:32:48 -0700 (PDT) MIME-Version: 1.0 References: <20211025230503.2650970-1-naoya.horiguchi@linux.dev> <20211025230503.2650970-2-naoya.horiguchi@linux.dev> In-Reply-To: <20211025230503.2650970-2-naoya.horiguchi@linux.dev> From: Yang Shi Date: Tue, 26 Oct 2021 18:32:36 -0700 Message-ID: Subject: Re: [PATCH v2 1/4] mm/hwpoison: mf_mutex for soft offline and unpoison To: Naoya Horiguchi Cc: Linux MM , Andrew Morton , David Hildenbrand , Oscar Salvador , Michal Hocko , Ding Hui , Tony Luck , "Aneesh Kumar K.V" , Miaohe Lin , Peter Xu , Naoya Horiguchi , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: douhzsfkxh6sjxryxyty8hxhcfiz9kpo X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 28C133000251 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=En4HPJgU; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf08.hostedemail.com: domain of shy828301@gmail.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-HE-Tag: 1635298362-536108 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: On Mon, Oct 25, 2021 at 4:06 PM Naoya Horiguchi wrote: > > From: Naoya Horiguchi > > Originally mf_mutex is introduced to serialize multiple MCE events, but > it's also helpful to exclude races among soft_offline_page() and > unpoison_memory(). So apply mf_mutex to them. My understanding is it is not that useful to make unpoison run parallel with memory_failure() and soft offline, so they can be serialized by mf_mutex and we could make the memory failure handler and soft offline simpler. If the above statement is correct, could you please tweak this commit log to reflect it with patch #2 squashed into this patch? > Signed-off-by: Naoya Horiguchi > --- > ChangeLog v2: > - add mutex_unlock() in "page already poisoned" path in soft_offline_page(). > (Thanks to Ding Hui) > --- > mm/memory-failure.c | 27 +++++++++++++++++++-------- > 1 file changed, 19 insertions(+), 8 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index fa9dda95a2a2..97297edfbd8e 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1628,6 +1628,8 @@ 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 +1656,6 @@ 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); > @@ -1978,6 +1979,7 @@ 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); > @@ -1988,28 +1990,30 @@ 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; > + goto unlock_mutex; > } > > /* > @@ -2020,7 +2024,7 @@ int unpoison_memory(unsigned long pfn) > 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)) { > @@ -2028,7 +2032,7 @@ 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); > @@ -2050,7 +2054,9 @@ int unpoison_memory(unsigned long pfn) > 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 +2237,12 @@ 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 +2260,7 @@ int soft_offline_page(unsigned long pfn, int flags) > } > } > > + mutex_unlock(&mf_mutex); > + > return ret; > } > -- > 2.25.1 >