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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FA0DC63798 for ; Fri, 20 Nov 2020 08:19:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4FDA22249 for ; Fri, 20 Nov 2020 08:19:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Ej6er/FV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbgKTITo (ORCPT ); Fri, 20 Nov 2020 03:19:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:34916 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725818AbgKTITm (ORCPT ); Fri, 20 Nov 2020 03:19:42 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1605860381; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QW9DfTvL/tP0pjyHObZ8HmfOn6WmxLL7a59EjdlXOnw=; b=Ej6er/FVxpJaDeALJNOBDD/dPe9P1i6ApIgIIaZINCNGCZGJuTHTpfc8cFPrJXlMjyPso6 7uCprUYzOh1UkFKX4H/cjLrMoQxK3KUtrRU9YB9ijmodh/taJY0flyr9MNiMdfX3R5D202 iT4VJBQEQ05ZaPtRwumvhUgP/b4vF4k= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D13B3AC0C; Fri, 20 Nov 2020 08:19:40 +0000 (UTC) Date: Fri, 20 Nov 2020 09:19:40 +0100 From: Michal Hocko To: Muchun Song Cc: corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com, willy@infradead.org, osalvador@suse.de, song.bao.hua@hisilicon.com, duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v5 15/21] mm/hugetlb: Set the PageHWPoison to the raw error page Message-ID: <20201120081940.GE3200@dhcp22.suse.cz> References: <20201120064325.34492-1-songmuchun@bytedance.com> <20201120064325.34492-16-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120064325.34492-16-songmuchun@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 20-11-20 14:43:19, Muchun Song wrote: > Because we reuse the first tail page, if we set PageHWPosion on a > tail page. It indicates that we may set PageHWPoison on a series > of pages. So we can use the head[4].mapping to record the real > error page index and set the raw error page PageHWPoison later. This really begs more explanation. Maybe I misremember but If there is a HWPoison hole in a hugepage then the whole page is demolished, no? If that is the case then why do we care about tail pages? > Signed-off-by: Muchun Song > --- > mm/hugetlb.c | 11 +++-------- > mm/hugetlb_vmemmap.h | 39 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 42 insertions(+), 8 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 055604d07046..b853aacd5c16 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1383,6 +1383,7 @@ static void __free_hugepage(struct hstate *h, struct page *page) > int i; > > alloc_huge_page_vmemmap(h, page); > + subpage_hwpoison_deliver(page); > > for (i = 0; i < pages_per_huge_page(h); i++) { > page[i].flags &= ~(1 << PG_locked | 1 << PG_error | > @@ -1944,14 +1945,8 @@ int dissolve_free_huge_page(struct page *page) > int nid = page_to_nid(head); > if (h->free_huge_pages - h->resv_huge_pages == 0) > goto out; > - /* > - * Move PageHWPoison flag from head page to the raw error page, > - * which makes any subpages rather than the error page reusable. > - */ > - if (PageHWPoison(head) && page != head) { > - SetPageHWPoison(page); > - ClearPageHWPoison(head); > - } > + > + set_subpage_hwpoison(head, page); > list_del(&head->lru); > h->free_huge_pages--; > h->free_huge_pages_node[nid]--; > diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h > index 779d3cb9333f..65e94436ffff 100644 > --- a/mm/hugetlb_vmemmap.h > +++ b/mm/hugetlb_vmemmap.h > @@ -20,6 +20,29 @@ void __init gather_vmemmap_pgtable_init(struct huge_bootmem_page *m, > void alloc_huge_page_vmemmap(struct hstate *h, struct page *head); > void free_huge_page_vmemmap(struct hstate *h, struct page *head); > > +static inline void subpage_hwpoison_deliver(struct page *head) > +{ > + struct page *page = head; > + > + if (PageHWPoison(head)) > + page = head + page_private(head + 4); > + > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + if (page != head) { > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > +static inline void set_subpage_hwpoison(struct page *head, struct page *page) > +{ > + if (PageHWPoison(head)) > + set_page_private(head + 4, page - head); > +} > + > static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) > { > return h->nr_free_vmemmap_pages; > @@ -56,6 +79,22 @@ static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head) > { > } > > +static inline void subpage_hwpoison_deliver(struct page *head) > +{ > +} > + > +static inline void set_subpage_hwpoison(struct page *head, struct page *page) > +{ > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + if (PageHWPoison(head) && page != head) { > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) > { > return 0; > -- > 2.11.0 > -- Michal Hocko SUSE Labs