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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF0AACCA47B for ; Thu, 2 Jun 2022 18:35:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238183AbiFBSff (ORCPT ); Thu, 2 Jun 2022 14:35:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238190AbiFBSf3 (ORCPT ); Thu, 2 Jun 2022 14:35:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10C282236A6 for ; Thu, 2 Jun 2022 11:35:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9BD6261729 for ; Thu, 2 Jun 2022 18:35:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2D47C385A5; Thu, 2 Jun 2022 18:35:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1654194928; bh=dx5VfC0KJJEmjKFa8DMIcRhOG5CmHOJh+M9ylaUABiE=; h=Date:To:From:Subject:From; b=VxeNGho0JRnGvmIQ/zumAYEodlUtHddoDKrENPo+3BOGAJHG80LUx8u8A8fXz5Dae 5IJraQKTp5v0Wjg7v6H5E9JO2fsfO3C3r0HSGX4+Hpcyi6siCX6ci+BbqgCFfqBJmV w3/kUTySEK0IH1MAu0TDJjdqZ6s8Vm5rhbcX7YhY= Date: Thu, 02 Jun 2022 11:35:27 -0700 To: mm-commits@vger.kernel.org, songmuchun@bytedance.com, shy828301@gmail.com, osalvador@suse.de, mike.kravetz@oracle.com, liushixin2@huawei.com, linmiaohe@huawei.com, david@redhat.com, naoya.horiguchi@nec.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch added to mm-unstable branch Message-Id: <20220602183527.F2D47C385A5@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage has been added to the -mm mm-unstable branch. Its filename is mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Naoya Horiguchi Subject: mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage Date: Thu, 2 Jun 2022 14:06:30 +0900 Currently if memory_failure() (modified to remove blocking code) is called on a page in some 1GB hugepage, memory error handling returns failure and the raw error page gets into undesirable state. The impact is small in production systems (just leaked single 4kB page), but this limits the test efficiency because unpoison doesn't work for it. So we can no longer create 1GB hugepage on the 1GB physical address range with such hwpoison pages, that could be an issue in testing on small systems. When a hwpoison page in a 1GB hugepage is handled, it's caught by the PageHWPoison check in free_pages_prepare() because the hugepage is broken down into raw error page and order is 0: if (unlikely(PageHWPoison(page)) && !order) { ... return false; } Then, the page is not sent to buddy and the page refcount is left 0. Originally this check is supposed to work when the error page is freed from page_handle_poison() (that is called from soft-offline), but now we are opening another path to call it, so the callers of __page_handle_poison() need to handle the case by considering the return value 0 as success. Then page refcount for hwpoison is properly incremented and now unpoison works. Link: https://lkml.kernel.org/r/20220602050631.771414-5-naoya.horiguchi@linux.dev Signed-off-by: Naoya Horiguchi Cc: David Hildenbrand Cc: Liu Shixin Cc: Miaohe Lin Cc: Mike Kravetz Cc: Muchun Song Cc: Oscar Salvador Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/memory-failure.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/mm/memory-failure.c~mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage +++ a/mm/memory-failure.c @@ -1044,7 +1044,6 @@ static int me_huge_page(struct page_stat res = truncate_error_page(hpage, page_to_pfn(p), mapping); unlock_page(hpage); } else { - res = MF_FAILED; unlock_page(hpage); /* * migration entry prevents later access on error hugepage, @@ -1052,9 +1051,11 @@ static int me_huge_page(struct page_stat * subpages. */ put_page(hpage); - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } } @@ -1602,9 +1603,11 @@ retry: */ if (res == 0) { unlock_page(head); - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } action_result(pfn, MF_MSG_FREE_HUGE, res); return res == MF_RECOVERED ? 0 : -EBUSY; _ Patches currently in -mm which might be from naoya.horiguchi@nec.com are mm-hwpoison-hugetlb-introduce-subpage_index_hwpoison-to-save-raw-error-page.patch mmhwpoison-set-pg_hwpoison-for-busy-hugetlb-pages.patch mm-hwpoison-make-__page_handle_poison-returns-int.patch mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch mm-hwpoison-enable-memory-error-handling-on-1gb-hugepage.patch