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From: Naoya Horiguchi To: Miaohe Lin Cc: linux-mm@kvack.org, Andrew Morton , David Hildenbrand , Mike Kravetz , Yang Shi , Oscar Salvador , Muchun Song , Jane Chu , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: [PATCH v8 1/4] mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage Message-ID: <20221025053559.GA2104800@ik1-406-35019.vs.sakura.ne.jp> References: <20221024062012.1520887-1-naoya.horiguchi@linux.dev> <20221024062012.1520887-2-naoya.horiguchi@linux.dev> <2484c6be-5075-2203-4f16-9cfdc4876e11@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <2484c6be-5075-2203-4f16-9cfdc4876e11@huawei.com> X-Migadu-Flow: FLOW_OUT ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666676170; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=lG01Ahpo4ENuldLEAS9Qh2m3uNUJs2/EyBGEGwc5EcI=; b=l2Qz9Rm2TNBlYZr+SUXwNC9nYEOnGDrioJKOIyHd0nVGeR0NC0+nzKMy2Ih5hlkLDs8ZoK 9x+7KEzC8UkCZlraZjDGRIBBCIRwMsV/8LrxaWMyxLyLdoAIL3iN2QE4ECpWlaeDyag6bx iamsAeb2zMV7bKNYrlznSh8Jesza9UM= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=img6RSRO; spf=pass (imf20.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666676170; a=rsa-sha256; cv=none; b=qKFTDY6GNNPv++YmVJ2ovflnvQE42cnaTjP8bO3SWkj2QZgw40OawvsMxu4wkjSzf+ApVs 1SYx0KYUWsIbFdIpdpJ0myRpFxeY6npcbNBmRUygQGqTfFzTOg3tMuTMXmGzhoeSHSwMqj idUAqul6DfILHC3GXQHMhSZ9Un+Ayw0= X-Rspamd-Queue-Id: E1D681C0009 Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=img6RSRO; spf=pass (imf20.hostedemail.com: domain of naoya.horiguchi@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=naoya.horiguchi@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Rspam-User: X-Rspamd-Server: rspam10 X-Stat-Signature: fcufo4k57r18fwdkehymnt7t64m45f6q X-HE-Tag: 1666676169-283583 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 Tue, Oct 25, 2022 at 10:38:11AM +0800, Miaohe Lin wrote: > On 2022/10/24 14:20, Naoya Horiguchi wrote: > > From: Naoya Horiguchi > > > > HWPoisoned page is not supposed to be accessed once marked, but currently > > such accesses can happen during memory hotremove because do_migrate_range() > > can be called before dissolve_free_huge_pages() is called. > > > > Clear HPageMigratable for hwpoisoned hugepages to prevent them from being > > migrated. This should be done in hugetlb_lock to avoid race against > > isolate_hugetlb(). > > > > get_hwpoison_huge_page() needs to have a flag to show it's called from > > unpoison to take refcount of hwpoisoned hugepages, so add it. > > > > Reported-by: Miaohe Lin > > Signed-off-by: Naoya Horiguchi > > Reviewed-by: Oscar Salvador > > Reviewed-by: Miaohe Lin > > --- > > ChangeLog v3 -> v7: > > - introduce TESTCLEARHPAGEFLAG() to determine the value of migratable_cleared > > Many thanks for update, Naoya. I'm sorry but TestClearHPageMigratable() might be somewhat > overkill. As we discussed in previous thread: > > """ > I think I might be nitpicking... But it seems ClearHPageMigratable is not enough here. > 1. In MF_COUNT_INCREASED case, we don't know whether HPageMigratable is set. > 2. Even if HPageMigratable is set, there might be a race window before we clear HPageMigratable? > So "*migratable_cleared = TestClearHPageMigratable" might be better? But I might be wrong. > """ > > The case 2 should be a dumb problem(sorry about it). HPageMigratable() is always cleared while holding > the hugetlb_lock which is already held by get_huge_page_for_hwpoison(). So the only case we should care > about is case 1 and that can be handled by below more efficient pattern: > if (HPageMigratable) > ClearHPageMigratable() > > So the overhead of test and clear atomic ops can be avoided. But this is trival. > > Anyway, this patch still looks good to me. And my Reviewed-by tag still applies. Many thanks. OK, so I replace this 1/4 with the following one, thank you. - Naoya Horiguchi --- From 22cbd7649d1e23db272306f8d066edb15d4e322c Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Tue, 25 Oct 2022 14:18:10 +0900 Subject: [PATCH v8 1/4] mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage HWPoisoned page is not supposed to be accessed once marked, but currently such accesses can happen during memory hotremove because do_migrate_range() can be called before dissolve_free_huge_pages() is called. Clear HPageMigratable for hwpoisoned hugepages to prevent them from being migrated. This should be done in hugetlb_lock to avoid race against isolate_hugetlb(). get_hwpoison_huge_page() needs to have a flag to show it's called from unpoison to take refcount of hwpoisoned hugepages, so add it. Reported-by: Miaohe Lin Signed-off-by: Naoya Horiguchi Reviewed-by: Oscar Salvador Reviewed-by: Miaohe Lin --- ChangeLog v7 -> v8: - remove TestClearHPageMigratable and reduce to test and clear separately. ChangeLog v3 -> v7: - introduce TESTCLEARHPAGEFLAG() to determine the value of migratable_cleared ChangeLog v3 -> v6: - introduce migratable_cleared to remember that HPageMigratable is cleared in error handling. It's needed to cancel when an error event is filtered by hwpoison_filter(). (Thanks to Miaohe) ChangeLog v2 -> v3 - move to the approach of clearing HPageMigratable instead of shifting dissolve_free_huge_pages. --- include/linux/hugetlb.h | 10 ++++++---- include/linux/mm.h | 6 ++++-- mm/hugetlb.c | 9 +++++---- mm/memory-failure.c | 21 +++++++++++++++++---- 4 files changed, 32 insertions(+), 14 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index a899bc76d677..3568b90b397d 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -183,8 +183,9 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to, long hugetlb_unreserve_pages(struct inode *inode, long start, long end, long freed); int isolate_hugetlb(struct page *page, struct list_head *list); -int get_hwpoison_huge_page(struct page *page, bool *hugetlb); -int get_huge_page_for_hwpoison(unsigned long pfn, int flags); +int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison); +int get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared); void putback_active_hugepage(struct page *page); void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason); void free_huge_page(struct page *page); @@ -391,12 +392,13 @@ static inline int isolate_hugetlb(struct page *page, struct list_head *list) return -EBUSY; } -static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb) +static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison) { return 0; } -static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags) +static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared) { return 0; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 58345f06a2f4..3da6283c9d30 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3246,9 +3246,11 @@ extern void shake_page(struct page *p); extern atomic_long_t num_poisoned_pages __read_mostly; extern int soft_offline_page(unsigned long pfn, int flags); #ifdef CONFIG_MEMORY_FAILURE -extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags); +extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared); #else -static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) +static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared) { return 0; } diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 931789a8f734..88d2dc756822 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -7292,7 +7292,7 @@ int isolate_hugetlb(struct page *page, struct list_head *list) return ret; } -int get_hwpoison_huge_page(struct page *page, bool *hugetlb) +int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison) { int ret = 0; @@ -7302,7 +7302,7 @@ int get_hwpoison_huge_page(struct page *page, bool *hugetlb) *hugetlb = true; if (HPageFreed(page)) ret = 0; - else if (HPageMigratable(page)) + else if (HPageMigratable(page) || unpoison) ret = get_page_unless_zero(page); else ret = -EBUSY; @@ -7311,12 +7311,13 @@ int get_hwpoison_huge_page(struct page *page, bool *hugetlb) return ret; } -int get_huge_page_for_hwpoison(unsigned long pfn, int flags) +int get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared) { int ret; spin_lock_irq(&hugetlb_lock); - ret = __get_huge_page_for_hwpoison(pfn, flags); + ret = __get_huge_page_for_hwpoison(pfn, flags, migratable_cleared); spin_unlock_irq(&hugetlb_lock); return ret; } diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 62cf1e0fbc8e..0ba7032be8c0 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1250,7 +1250,7 @@ static int __get_hwpoison_page(struct page *page, unsigned long flags) int ret = 0; bool hugetlb = false; - ret = get_hwpoison_huge_page(head, &hugetlb); + ret = get_hwpoison_huge_page(head, &hugetlb, false); if (hugetlb) return ret; @@ -1340,7 +1340,7 @@ static int __get_unpoison_page(struct page *page) int ret = 0; bool hugetlb = false; - ret = get_hwpoison_huge_page(head, &hugetlb); + ret = get_hwpoison_huge_page(head, &hugetlb, true); if (hugetlb) return ret; @@ -1791,7 +1791,8 @@ void hugetlb_clear_page_hwpoison(struct page *hpage) * -EBUSY - the hugepage is busy (try to retry) * -EHWPOISON - the hugepage is already hwpoisoned */ -int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) +int __get_huge_page_for_hwpoison(unsigned long pfn, int flags, + bool *migratable_cleared) { struct page *page = pfn_to_page(pfn); struct page *head = compound_head(page); @@ -1821,6 +1822,15 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) goto out; } + /* + * Clearing HPageMigratable for hwpoisoned hugepages to prevent them + * from being migrated by memory hotremove. + */ + if (count_increased && HPageMigratable(head)) { + ClearHPageMigratable(head); + *migratable_cleared = true; + } + return ret; out: if (count_increased) @@ -1840,10 +1850,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb struct page *p = pfn_to_page(pfn); struct page *head; unsigned long page_flags; + bool migratable_cleared = false; *hugetlb = 1; retry: - res = get_huge_page_for_hwpoison(pfn, flags); + res = get_huge_page_for_hwpoison(pfn, flags, &migratable_cleared); if (res == 2) { /* fallback to normal page handling */ *hugetlb = 0; return 0; @@ -1867,6 +1878,8 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb if (hwpoison_filter(p)) { hugetlb_clear_page_hwpoison(head); + if (migratable_cleared) + SetHPageMigratable(head); unlock_page(head); if (res == 1) put_page(head);