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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1656556104; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wOMgnwsmQWT0PlMYH+FuGsur4UNydG+XcrxtKVbnrBs=; b=EikZrr/igoYVd4UDlTbpVEFA6l/Mv89057tUmr2NRCqf8qX6pBQS7z1kkUfyklkSLy/Xmk Gy0oUY+c/UJYIckBwTl/90qL2gwfuembtzzh9iuXFUcQojLzAIv3gf4nlU9/e8qrLJPUcK D4gW2f0M1O2td7MBg8L9BvjULkAfK5E= From: Naoya Horiguchi To: linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , Mike Kravetz , Miaohe Lin , Liu Shixin , Yang Shi , Oscar Salvador , Muchun Song , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: [PATCH v3 4/9] mm, hwpoison, hugetlb: support saving mechanism of raw error pages Date: Thu, 30 Jun 2022 11:27:50 +0900 Message-Id: <20220630022755.3362349-5-naoya.horiguchi@linux.dev> In-Reply-To: <20220630022755.3362349-1-naoya.horiguchi@linux.dev> References: <20220630022755.3362349-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656556106; a=rsa-sha256; cv=none; b=haDm/y1WLlZqQ3EBUkMcX50U45ketzJSE0gIEstjHJpuNq2mshxxMMOLTzOUKUdIz07Q2z B2ZtP/rVAjLJK386OAMzHEI7Kyc8tpWdBU9ReoG3ZqN0W0NTnYC4vjFTF+ldSFUGLr/5el xxaDNITd87/xGmLPuO+LQFXIQBZDuF8= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="EikZrr/i"; spf=pass (imf15.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656556106; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wOMgnwsmQWT0PlMYH+FuGsur4UNydG+XcrxtKVbnrBs=; b=UVv70Ve8Ggyhg67QpT82AhuvwRhxpSfcUNChY+XhmhV12WZqqI0AoiuzoZtMJR17HRTqCz RTy0zu4p8EfOg1P/jhlffsWtVY3jO29wMd/tn6GhWrjs0REUEPP7UTimQFPYa9BrotgEgr rw/3qDEH0byzBxB/ZC/yq5JmWyeNifg= X-Rspam-User: X-Rspamd-Server: rspam04 Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="EikZrr/i"; spf=pass (imf15.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Stat-Signature: 1mta3kqwjigf9ni9uh9rduefrnxtzxg6 X-Rspamd-Queue-Id: A28BBA0033 X-HE-Tag: 1656556105-557600 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: 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 pages is lost. Use the private field of a few tail pages to keep that information. The code path of shrinking hugepage pool uses this info to try delayed dissolve. In order to remember multiple errors in a hugepage, a singly-linked list originated from SUBPAGE_INDEX_HWPOISON-th tail page is constructed. Only simple operations (adding an entry or clearing all) are required and the list is assumed not to be very long, so this simple data structure should be enough. If we failed to save raw error info, the hwpoison hugepage has errors on unknown subpage, then this new saving mechanism does not work any more, so disable saving new raw error info and freeing hwpoison hugepages. Signed-off-by: Naoya Horiguchi --- v2 -> v3: - remove duplicate "return ret" lines, - use GFP_ATOMIC instead of GFP_KERNEL, - introduce HPageRawHwpUnreliable pseudo flag (suggested by Muchun), - hugetlb_clear_page_hwpoison removes raw_hwp_page list even if HPageRawHwpUnreliable is true, (by Miaohe) v1 -> v2: - support hwpoison hugepage with multiple errors, - moved the new interface functions to mm/memory-failure.c, - define additional subpage index SUBPAGE_INDEX_HWPOISON_UNRELIABLE, - stop freeing/dissolving hwpoison hugepages with unreliable raw error info, - drop hugetlb_clear_page_hwpoison() in dissolve_free_huge_page() because that's done in update_and_free_page(), - move setting/clearing PG_hwpoison flag to the new interfaces, - checking already hwpoisoned or not on a subpage basis. 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 Signed-off-by: Naoya Horiguchi --- include/linux/hugetlb.h | 18 +++++++++- mm/hugetlb.c | 39 ++++++++++---------- mm/memory-failure.c | 80 +++++++++++++++++++++++++++++++++++++++-- 3 files changed, 114 insertions(+), 23 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index e4cff27d1198..bd92a1e9a97b 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, }; @@ -550,7 +553,7 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, * Synchronization: Initially set after new page allocation with no * locking. When examined and modified during migration processing * (isolate, migrate, putback) the hugetlb_lock is held. - * HPG_temporary - - Set on a page that is temporarily allocated from the buddy + * HPG_temporary -- Set on a page that is temporarily allocated from the buddy * allocator. Typically used for migration target pages when no pages * are available in the pool. The hugetlb free page path will * immediately free pages with this flag set to the buddy allocator. @@ -560,6 +563,8 @@ generic_hugetlb_get_unmapped_area(struct file *file, unsigned long addr, * HPG_freed - Set when page is on the free lists. * Synchronization: hugetlb_lock held for examination and modification. * HPG_vmemmap_optimized - Set when the vmemmap pages of the page are freed. + * HPG_raw_hwp_unreliable - Set when the hugetlb page has a hwpoison sub-page + * that is not tracked by raw_hwp_page list. */ enum hugetlb_page_flags { HPG_restore_reserve = 0, @@ -567,6 +572,7 @@ enum hugetlb_page_flags { HPG_temporary, HPG_freed, HPG_vmemmap_optimized, + HPG_raw_hwp_unreliable, __NR_HPAGEFLAGS, }; @@ -613,6 +619,7 @@ HPAGEFLAG(Migratable, migratable) HPAGEFLAG(Temporary, temporary) HPAGEFLAG(Freed, freed) HPAGEFLAG(VmemmapOptimized, vmemmap_optimized) +HPAGEFLAG(RawHwpUnreliable, raw_hwp_unreliable) #ifdef CONFIG_HUGETLB_PAGE @@ -798,6 +805,15 @@ 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 +extern int hugetlb_clear_page_hwpoison(struct page *hpage); +#else +static inline int hugetlb_clear_page_hwpoison(struct page *hpage) +{ + return 0; +} +#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 4c30f3fcfe50..0937638fcb36 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1541,17 +1541,15 @@ static void __update_and_free_page(struct hstate *h, struct page *page) if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; - if (hugetlb_vmemmap_alloc(h, page)) { - spin_lock_irq(&hugetlb_lock); - /* - * If we cannot allocate vmemmap pages, just refuse to free the - * page and put the page back on the hugetlb free list and treat - * as a surplus page. - */ - add_hugetlb_page(h, page, true); - spin_unlock_irq(&hugetlb_lock); - return; - } + if (hugetlb_vmemmap_alloc(h, page)) + goto fail; + + /* + * Move PageHWPoison flag from head page to the raw error pages, + * which makes any healthy subpages reusable. + */ + if (unlikely(PageHWPoison(page) && hugetlb_clear_page_hwpoison(page))) + goto fail; for (i = 0; i < pages_per_huge_page(h); i++, subpage = mem_map_next(subpage, page, i)) { @@ -1572,6 +1570,16 @@ static void __update_and_free_page(struct hstate *h, struct page *page) } else { __free_pages(page, huge_page_order(h)); } + return; +fail: + spin_lock_irq(&hugetlb_lock); + /* + * If we cannot allocate vmemmap pages or cannot identify raw hwpoison + * subpages reliably, just refuse to free the page and put the page + * back on the hugetlb free list and treat as a surplus page. + */ + add_hugetlb_page(h, page, true); + spin_unlock_irq(&hugetlb_lock); } /* @@ -2115,15 +2123,6 @@ int dissolve_free_huge_page(struct page *page) */ rc = hugetlb_vmemmap_alloc(h, head); if (!rc) { - /* - * 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); - } update_and_free_page(h, head, false); } else { spin_lock_irq(&hugetlb_lock); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index fb3feb1f363e..71414eb90a7a 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1499,6 +1499,82 @@ static int try_to_split_thp_page(struct page *page, const char *msg) } #ifdef CONFIG_HUGETLB_PAGE +/* + * Struct raw_hwp_page represents information about "raw error page", + * constructing singly linked list originated from ->private field of + * SUBPAGE_INDEX_HWPOISON-th tail page. + */ +struct raw_hwp_page { + struct llist_node node; + struct page *page; +}; + +static inline struct llist_head *raw_hwp_list_head(struct page *hpage) +{ + return (struct llist_head *)&page_private(hpage + SUBPAGE_INDEX_HWPOISON); +} + +static inline int hugetlb_set_page_hwpoison(struct page *hpage, + struct page *page) +{ + struct llist_head *head; + struct raw_hwp_page *raw_hwp; + struct llist_node *t, *tnode; + int ret; + + /* + * Once the hwpoison hugepage has lost reliable raw error info, + * there is little meaning to keep additional error info precisely, + * so skip to add additional raw error info. + */ + if (HPageRawHwpUnreliable(hpage)) + return -EHWPOISON; + head = raw_hwp_list_head(hpage); + llist_for_each_safe(tnode, t, head->first) { + struct raw_hwp_page *p = container_of(tnode, struct raw_hwp_page, node); + + if (p->page == page) + return -EHWPOISON; + } + + ret = TestSetPageHWPoison(hpage) ? -EHWPOISON : 0; + /* the first error event will be counted in action_result(). */ + if (ret) + num_poisoned_pages_inc(); + + raw_hwp = kmalloc(sizeof(struct raw_hwp_page), GFP_ATOMIC); + if (raw_hwp) { + raw_hwp->page = page; + llist_add(&raw_hwp->node, head); + } else { + /* + * Failed to save raw error info. We no longer trace all + * hwpoisoned subpages, and we need refuse to free/dissolve + * this hwpoisoned hugepage. + */ + SetHPageRawHwpUnreliable(hpage); + } + return ret; +} + +inline int hugetlb_clear_page_hwpoison(struct page *hpage) +{ + struct llist_head *head; + struct llist_node *t, *tnode; + + if (!HPageRawHwpUnreliable(hpage)) + ClearPageHWPoison(hpage); + head = raw_hwp_list_head(hpage); + llist_for_each_safe(tnode, t, head->first) { + struct raw_hwp_page *p = container_of(tnode, struct raw_hwp_page, node); + + SetPageHWPoison(p->page); + kfree(p); + } + llist_del_all(head); + return 0; +} + /* * Called from hugetlb code with hugetlb_lock held. * @@ -1533,7 +1609,7 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) goto out; } - if (TestSetPageHWPoison(head)) { + if (hugetlb_set_page_hwpoison(head, page)) { ret = -EHWPOISON; goto out; } @@ -1585,7 +1661,7 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb lock_page(head); if (hwpoison_filter(p)) { - ClearPageHWPoison(head); + hugetlb_clear_page_hwpoison(head); res = -EOPNOTSUPP; goto out; } -- 2.25.1