From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D985B76026 for ; Mon, 20 Jan 2025 06:24:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737354273; cv=none; b=ciMwgBh7Um8WeqAH4b59MEUcPzt9h8UCCYoa5pnoEQOtX264TxjnJGGWJ+LXjVrdFboW4yY5zfmCbpEkjyN41uaLTs1V131AVTIH618vyDU+XR1VklYNPY48Zc+bjblO9VwUnm11mOXd7x42dBhrhv359QzV/Py8pGEQJkHJIKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737354273; c=relaxed/simple; bh=LVAjsWe9aBHXdHPfcQ3FSSTp+sXolB6zFitaRdDoXPc=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=jHLHl+LU9biFaK5kivtkgPJsieYUR3HVL74LW947X2YdwoszB3OwOQMBjovjTmS+Sbtx+ibOeQeU6hHpWCDBPu5rrFrn1q1Ealj+L0ogoY+51dUSRWBjrvwcWaPfM6cA3KfcrF2P9zokWcJqN9UAezXbe/TB0Bjq2Pi6q6NGXbA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.35 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.163]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4Yc0b33mwPz1V55W; Mon, 20 Jan 2025 14:21:03 +0800 (CST) Received: from kwepemd200019.china.huawei.com (unknown [7.221.188.193]) by mail.maildlp.com (Postfix) with ESMTPS id 87A02180042; Mon, 20 Jan 2025 14:24:20 +0800 (CST) Received: from [10.173.127.72] (10.173.127.72) by kwepemd200019.china.huawei.com (7.221.188.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 20 Jan 2025 14:24:19 +0800 Subject: Re: [PATCH v2 1/3] mm: memory-failure: update ttu flag inside unmap_poisoned_folio To: Wupeng Ma CC: , , , , , , References: <20250116061657.227027-1-mawupeng1@huawei.com> <20250116061657.227027-2-mawupeng1@huawei.com> From: Miaohe Lin Message-ID: <21674fcc-bd5d-3e32-6e45-f0a16ab93202@huawei.com> Date: Mon, 20 Jan 2025 14:24:18 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250116061657.227027-2-mawupeng1@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemd200019.china.huawei.com (7.221.188.193) On 2025/1/16 14:16, Wupeng Ma wrote: > From: Ma Wupeng Thanks for your patch. Some nits below. > > Commit 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to > TTU_HWPOISON") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON > in order to stop send SIGBUS signal when accessing an error page after > a memory error on a clean folio. However during page migration, anon > folio must be set with TTU_HWPOISON during unmap_*(). For pagecache > we need some policy just like the one in hwpoison_user_mappings to > set this flag. So move this policy from hwpoison_user_mappings to > unmap_poisoned_folio to handle this waring properly. s/waring/warning/g > > Waring will be produced during unamp poison folio with the following log: s/Waring/Warning/g > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 try_to_unmap_one+0x8fc/0xd3c > Modules linked in: > CPU: 1 UID: 0 PID: 365 Comm: bash Tainted: G W 6.13.0-rc1-00018-gacdb4bbda7ab #42 > Tainted: [W]=WARN > Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 > pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : try_to_unmap_one+0x8fc/0xd3c > lr : try_to_unmap_one+0x3dc/0xd3c > Call trace: > try_to_unmap_one+0x8fc/0xd3c (P) > try_to_unmap_one+0x3dc/0xd3c (L) > rmap_walk_anon+0xdc/0x1f8 > rmap_walk+0x3c/0x58 > try_to_unmap+0x88/0x90 > unmap_poisoned_folio+0x30/0xa8 > do_migrate_range+0x4a0/0x568 > offline_pages+0x5a4/0x670 > memory_block_action+0x17c/0x374 > memory_subsys_offline+0x3c/0x78 > device_offline+0xa4/0xd0 > state_store+0x8c/0xf0 > dev_attr_store+0x18/0x2c > sysfs_kf_write+0x44/0x54 > kernfs_fop_write_iter+0x118/0x1a8 > vfs_write+0x3a8/0x4bc > ksys_write+0x6c/0xf8 > __arm64_sys_write+0x1c/0x28 > invoke_syscall+0x44/0x100 > el0_svc_common.constprop.0+0x40/0xe0 > do_el0_svc+0x1c/0x28 > el0_svc+0x30/0xd0 > el0t_64_sync_handler+0xc8/0xcc > el0t_64_sync+0x198/0x19c > ---[ end trace 0000000000000000 ]--- > > Fixes: 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON") > Signed-off-by: Ma Wupeng > Suggested-by: David Hildenbrand > --- > mm/internal.h | 5 ++-- > mm/memory-failure.c | 61 +++++++++++++++++++++++---------------------- > mm/memory_hotplug.c | 3 ++- > 3 files changed, 36 insertions(+), 33 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 9826f7dce607..3caee67c0abd 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1102,7 +1102,7 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask) > * mm/memory-failure.c > */ > #ifdef CONFIG_MEMORY_FAILURE > -void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu); > +int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill); > void shake_folio(struct folio *folio); > extern int hwpoison_filter(struct page *p); > > @@ -1125,8 +1125,9 @@ unsigned long page_mapped_in_vma(const struct page *page, > struct vm_area_struct *vma); > > #else > -static inline void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) > +static inline int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill); > { > + return -EBUSY; > } > #endif > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index a7b8ccd29b6f..b5212b6e330a 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1556,8 +1556,34 @@ static int get_hwpoison_page(struct page *p, unsigned long flags) > return ret; > } > > -void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) > +int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill) > { > + enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_HWPOISON; > + struct address_space *mapping; > + > + if (folio_test_swapcache(folio)) { > + pr_err("%#lx: keeping poisoned page in swap cache\n", pfn); > + ttu &= ~TTU_HWPOISON; > + } > + > + /* > + * Propagate the dirty bit from PTEs to struct page first, because we > + * need this to decide if we should kill or just drop the page. > + * XXX: the dirty test could be racy: set_page_dirty() may not always > + * be called inside page lock (it's recommended but not enforced). > + */ > + mapping = folio_mapping(folio); > + if (!must_kill && !folio_test_dirty(folio) && mapping && > + mapping_can_writeback(mapping)) { > + if (folio_mkclean(folio)) { > + folio_set_dirty(folio); > + } else { > + ttu &= ~TTU_HWPOISON; > + pr_info("%#lx: corrupted page was clean: dropped without side effects\n", > + pfn); > + } > + } > + > if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { > struct address_space *mapping; > > @@ -1572,7 +1598,7 @@ void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) > if (!mapping) { > pr_info("%#lx: could not lock mapping for mapped hugetlb folio\n", > folio_pfn(folio)); > - return; > + return -EBUSY; > } > > try_to_unmap(folio, ttu|TTU_RMAP_LOCKED); > @@ -1580,6 +1606,8 @@ void unmap_poisoned_folio(struct folio *folio, enum ttu_flags ttu) > } else { > try_to_unmap(folio, ttu); > } > + > + return folio_mapped(folio) ? -EBUSY : 0; Do we really need this return value? It's unused in do_migrate_range(). Thanks. .