[PATCH OLK-6.6 0/2] Add Support for Disabling Hugetlb in soft_offline_page
Backport the following patch to add the ability to disable Hugetlb in soft_offline_page: - mm/memory-failure: userspace controls soft-offlining pages - mm/memory-failure: support disabling soft offline for HugeTLB pages Jiaqi Yan (1): mm/memory-failure: userspace controls soft-offlining pages Kyle Meyer (1): mm/memory-failure: support disabling soft offline for HugeTLB pages .../ABI/testing/sysfs-memory-page-offline | 3 ++ mm/memory-failure.c | 33 +++++++++++++++++-- 2 files changed, 34 insertions(+), 2 deletions(-) -- 2.43.0
From: Jiaqi Yan <jiaqiyan@google.com> mainline inclusion from mainline-v6.11-rc1 commit 56374430c5dfcf6d4f1df79514f797b45fbd0485 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID6J4B Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Correctable memory errors are very common on servers with large amount of memory, and are corrected by ECC. Soft offline is kernel's additional recovery handling for memory pages having (excessive) corrected memory errors. Impacted page is migrated to a healthy page if inuse; the original page is discarded for any future use. The actual policy on whether (and when) to soft offline should be maintained by userspace, especially in case of an 1G HugeTLB page. Soft-offline dissolves the HugeTLB page, either in-use or free, into chunks of 4K pages, reducing HugeTLB pool capacity by 1 hugepage. If userspace has not acknowledged such behavior, it may be surprised when later failed to mmap hugepages due to lack of hugepages. In case of a transparent hugepage, it will be split into 4K pages as well; userspace will stop enjoying the transparent performance. In addition, discarding the entire 1G HugeTLB page only because of corrected memory errors sounds very costly and kernel better not doing under the hood. But today there are at least 2 such cases doing so: 1. when GHES driver sees both GHES_SEV_CORRECTED and CPER_SEC_ERROR_THRESHOLD_EXCEEDED after parsing CPER. 2. RAS Correctable Errors Collector counts correctable errors per PFN and when the counter for a PFN reaches threshold In both cases, userspace has no control of the soft offline performed by kernel's memory failure recovery. This commit gives userspace the control of softofflining any page: kernel only soft offlines raw page / transparent hugepage / HugeTLB hugepage if userspace has agreed to. The interface to userspace is a new sysctl at /proc/sys/vm/enable_soft_offline. By default its value is set to 1 to preserve existing behavior in kernel. When set to 0, soft-offline (e.g. MADV_SOFT_OFFLINE) will fail with EOPNOTSUPP. [jiaqiyan@google.com: v7] Link: https://lkml.kernel.org/r/20240628205958.2845610-3-jiaqiyan@google.com Link: https://lkml.kernel.org/r/20240626050818.2277273-3-jiaqiyan@google.com Signed-off-by: Jiaqi Yan <jiaqiyan@google.com> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Frank van der Linden <fvdl@google.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lance Yang <ioworker0@gmail.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Conflicts: mm/memory-failure.c [Wupeng Ma: context conflicts] Signed-off-by: Wupeng Ma <mawupeng1@huawei.com> --- mm/memory-failure.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 321eb6e92246..3388acc996e2 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -69,6 +69,8 @@ static int sysctl_memory_failure_early_kill __read_mostly; static int sysctl_memory_failure_recovery __read_mostly = 1; +static int sysctl_enable_soft_offline __read_mostly = 1; + atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); static bool hw_memory_failure __read_mostly = false; @@ -142,6 +144,15 @@ static struct ctl_table memory_failure_table[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, + { + .procname = "enable_soft_offline", + .data = &sysctl_enable_soft_offline, + .maxlen = sizeof(sysctl_enable_soft_offline), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, { } }; @@ -2808,8 +2819,9 @@ static int soft_offline_in_use_page(struct page *page) * @pfn: pfn to soft-offline * @flags: flags. Same as memory_failure(). * - * Returns 0 on success - * -EOPNOTSUPP for hwpoison_filter() filtered the error event + * Returns 0 on success, + * -EOPNOTSUPP for hwpoison_filter() filtered the error event, or + * disabled by /proc/sys/vm/enable_soft_offline, * < 0 otherwise negated errno. * * Soft offline a page, by migration or invalidation, @@ -2845,6 +2857,12 @@ int soft_offline_page(unsigned long pfn, int flags) return -EIO; } + if (!sysctl_enable_soft_offline) { + pr_info_once("disabled by /proc/sys/vm/enable_soft_offline\n"); + put_ref_page(pfn, flags); + return -EOPNOTSUPP; + } + mutex_lock(&mf_mutex); if (PageHWPoison(page)) { -- 2.43.0
From: Kyle Meyer <kyle.meyer@hpe.com> maillist inclusion category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID6J4B Reference: https://lore.kernel.org/all/aMiu_Uku6Y5ZbuhM@hpe.com/T/#u -------------------------------- Some BIOS suppress ("cloak") corrected memory errors until a threshold is reached. Once that threshold is reached, BIOS reports a CPER with the "error threshold exceeded" bit set via GHES and the corresponding page is soft offlined. BIOS does not know the page type of the corresponding page. If the corresponding page happens to be a HugeTLB page, it will be dissolved, permanently reducing the HugeTLB page pool. This can be problematic for workloads that depend on a fixed number of HugeTLB pages. Currently, soft offline must be disabled to prevent HugeTLB pages from being soft offlined. This patch provides a middle ground. Soft offline can be disabled for HugeTLB pages while remaining enabled for non-HugeTLB pages, preserving the benefits of soft offline without the risk of BIOS soft offlining HugeTLB pages. Commit 56374430c5dfc ("mm/memory-failure: userspace controls soft-offlining pages") introduced the following sysctl interface to control soft offline: /proc/sys/vm/enable_soft_offline The interface does not distinguish between page types: 0 - Soft offline is disabled 1 - Soft offline is enabled Convert enable_soft_offline to a bitmask and support disabling soft offline for HugeTLB pages: Bits: 0 - Enable soft offline 1 - Disable soft offline for HugeTLB pages Supported values: 0 - Soft offline is disabled 1 - Soft offline is enabled 3 - Soft offline is enabled (disabled for HugeTLB pages) Existing behavior is preserved. Update documentation and HugeTLB soft offline self tests. Tony said: : Recap of original problem is that some BIOS keep track of error : threshold per-rank and use this GHES mechanism to report threshold : exceeded on the rank. : : Systems that stay up a long time can accumulate enough soft errors to : trigger this threshold. But the action of taking a page offline isn't : going to help. For a 4K page this is merely annoying. For 1G page it : can mess things up badly. : : My original patch for this just skipped the GHES->offline process for : huge pages. But I wasn't aware of the sysctl control. That provides a : better solution. Link: https://lkml.kernel.org/r/aMiu_Uku6Y5ZbuhM@hpe.com Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com> Reported-by: Shawn Fan <shawn.fan@intel.com> Suggested-by: Tony Luck <tony.luck@intel.com> Cc: Borislav Betkov <bp@alien8.de> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jan Kara <jack@suse.cz> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Clapinski <mclapinski@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Russ Anderson <russ.anderson@hpe.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yafang <laoar.shao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Conflicts: mm/memory-failure.c [Wupeng Ma: context conflicts] Signed-off-by: Wupeng Ma <mawupeng1@huawei.com> --- .../ABI/testing/sysfs-memory-page-offline | 3 +++ mm/memory-failure.c | 17 ++++++++++++++--- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-memory-page-offline b/Documentation/ABI/testing/sysfs-memory-page-offline index 00f4e35f916f..d3f05ed6605e 100644 --- a/Documentation/ABI/testing/sysfs-memory-page-offline +++ b/Documentation/ABI/testing/sysfs-memory-page-offline @@ -20,6 +20,9 @@ Description: number, or a error when the offlining failed. Reading the file is not allowed. + Soft-offline can be controlled via sysctl, see: + Documentation/admin-guide/sysctl/vm.rst + What: /sys/devices/system/memory/hard_offline_page Date: Sep 2009 KernelVersion: 2.6.33 diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 3388acc996e2..87128fb1489c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -65,11 +65,14 @@ #include "internal.h" #include "ras/ras_event.h" +#define SOFT_OFFLINE_ENABLED BIT(0) +#define SOFT_OFFLINE_SKIP_HUGETLB BIT(1) + static int sysctl_memory_failure_early_kill __read_mostly; static int sysctl_memory_failure_recovery __read_mostly = 1; -static int sysctl_enable_soft_offline __read_mostly = 1; +static int sysctl_enable_soft_offline __read_mostly = SOFT_OFFLINE_ENABLED; atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); @@ -151,7 +154,7 @@ static struct ctl_table memory_failure_table[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, + .extra2 = SYSCTL_THREE, }, { } }; @@ -2857,12 +2860,20 @@ int soft_offline_page(unsigned long pfn, int flags) return -EIO; } - if (!sysctl_enable_soft_offline) { + if (!(sysctl_enable_soft_offline & SOFT_OFFLINE_ENABLED)) { pr_info_once("disabled by /proc/sys/vm/enable_soft_offline\n"); put_ref_page(pfn, flags); return -EOPNOTSUPP; } + if (sysctl_enable_soft_offline & SOFT_OFFLINE_SKIP_HUGETLB) { + if (folio_test_hugetlb(pfn_folio(pfn))) { + pr_info_once("disabled for HugeTLB pages by /proc/sys/vm/enable_soft_offline\n"); + put_ref_page(pfn, flags); + return -EOPNOTSUPP; + } + } + mutex_lock(&mf_mutex); if (PageHWPoison(page)) { -- 2.43.0
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