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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09B08C43334 for ; Tue, 7 Jun 2022 12:46:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7DB788D0008; Tue, 7 Jun 2022 08:46:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 78A798D0003; Tue, 7 Jun 2022 08:46:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 679B48D0008; Tue, 7 Jun 2022 08:46:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 59BD28D0003 for ; Tue, 7 Jun 2022 08:46:02 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2A23320D0C for ; Tue, 7 Jun 2022 12:46:02 +0000 (UTC) X-FDA: 79551412164.28.48D53E0 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf29.hostedemail.com (Postfix) with ESMTP id D1784120068 for ; Tue, 7 Jun 2022 12:45:45 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LHVPf1X0XzRjGq; Tue, 7 Jun 2022 20:42:46 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 7 Jun 2022 20:45:57 +0800 Subject: Re: [PATCH v1 1/5] mm, hwpoison, hugetlb: introduce SUBPAGE_INDEX_HWPOISON to save raw error page To: Naoya Horiguchi CC: Andrew Morton , David Hildenbrand , Mike Kravetz , Liu Shixin , Yang Shi , Oscar Salvador , Muchun Song , Naoya Horiguchi , , Linux-MM References: <20220602050631.771414-1-naoya.horiguchi@linux.dev> <20220602050631.771414-2-naoya.horiguchi@linux.dev> From: Miaohe Lin Message-ID: <69a451c3-8845-15cd-1767-9eccd5a5585d@huawei.com> Date: Tue, 7 Jun 2022 20:45:56 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20220602050631.771414-2-naoya.horiguchi@linux.dev> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D1784120068 X-Stat-Signature: n5tdeeqrjrxne5tid6hj1jnhs4egc8n3 X-Rspam-User: Authentication-Results: imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1654605945-32493 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 2022/6/2 13:06, Naoya Horiguchi wrote: > From: Naoya Horiguchi > > When handling memory error on a hugetlb page, the error handler tries to > dissolve and turn it into 4kB pages. If it's successfully dissolved, > PageHWPoison flag is moved to the raw error page, so that's all right. > However, dissolve sometimes fails, then the error page is left as > hwpoisoned hugepage. It's useful if we can retry to dissolve it to save > healthy pages, but that's not possible now because the information about > where the raw error page is lost. > > Use the private field of a tail page to keep that information. The code > path of shrinking hugepage pool used this info to try delayed dissolve. > This only keeps one hwpoison page for now, which might be OK because it's > simple and multiple hwpoison pages in a hugepage can be rare. But it can Yeah, multiple hwpoison pages in a hugepage might indicate that there are other problems. > be extended in the future. Since 1GB hugepage is going to be supported, only keeping one hwpoison page might not be enough soon. ;) > > Signed-off-by: Naoya Horiguchi Reviewed-by: Miaohe Lin Thanks! > --- > ChangeLog since previous post on 4/27: > - fixed typo in patch description (by Miaohe) > - fixed config value in #ifdef statement (by Miaohe) > - added sentences about "multiple hwpoison pages" scenario in patch > description > --- > include/linux/hugetlb.h | 24 ++++++++++++++++++++++++ > mm/hugetlb.c | 9 +++++++++ > mm/memory-failure.c | 2 ++ > 3 files changed, 35 insertions(+) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index ac2a1d758a80..a5341a3a0d4b 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -42,6 +42,9 @@ enum { > SUBPAGE_INDEX_CGROUP, /* reuse page->private */ > SUBPAGE_INDEX_CGROUP_RSVD, /* reuse page->private */ > __MAX_CGROUP_SUBPAGE_INDEX = SUBPAGE_INDEX_CGROUP_RSVD, > +#endif > +#ifdef CONFIG_MEMORY_FAILURE > + SUBPAGE_INDEX_HWPOISON, > #endif > __NR_USED_SUBPAGE, > }; > @@ -784,6 +787,27 @@ extern int dissolve_free_huge_page(struct page *page); > extern int dissolve_free_huge_pages(unsigned long start_pfn, > unsigned long end_pfn); > > +#ifdef CONFIG_MEMORY_FAILURE > +/* > + * pointer to raw error page is located in hpage[SUBPAGE_INDEX_HWPOISON].private > + */ > +static inline struct page *hugetlb_page_hwpoison(struct page *hpage) > +{ > + return (void *)page_private(hpage + SUBPAGE_INDEX_HWPOISON); > +} > + > +static inline void hugetlb_set_page_hwpoison(struct page *hpage, > + struct page *page) > +{ > + set_page_private(hpage + SUBPAGE_INDEX_HWPOISON, (unsigned long)page); > +} > +#else > +static inline struct page *hugetlb_page_hwpoison(struct page *hpage) > +{ > + return NULL; > +} > +#endif > + > #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION > #ifndef arch_hugetlb_migration_supported > static inline bool arch_hugetlb_migration_supported(struct hstate *h) > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index f8e048b939c7..6867ea8345d1 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1547,6 +1547,15 @@ static void __update_and_free_page(struct hstate *h, struct page *page) > return; > } > > + if (unlikely(PageHWPoison(page))) { > + struct page *raw_error = hugetlb_page_hwpoison(page); > + > + if (raw_error && raw_error != page) { > + SetPageHWPoison(raw_error); > + ClearPageHWPoison(page); > + } > + } > + > for (i = 0; i < pages_per_huge_page(h); > i++, subpage = mem_map_next(subpage, page, i)) { > subpage->flags &= ~(1 << PG_locked | 1 << PG_error | > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 66edaa7e5092..056dbb2050f8 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1534,6 +1534,8 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) > goto out; > } > > + hugetlb_set_page_hwpoison(head, page); > + > return ret; > out: > if (count_increased) >