From: Kyle Meyer <kyle.meyer@hpe.com> maillist inclusion category: feature bugzilla: https://gitee.com/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> --- .../ABI/testing/sysfs-memory-page-offline | 3 +++ kernel/sysctl.c | 2 +- mm/memory-failure.c | 16 ++++++++++++++-- 3 files changed, 18 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-memory-page-offline b/Documentation/ABI/testing/sysfs-memory-page-offline index e14703f12fdf..93285bbadc9e 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/kernel/sysctl.c b/kernel/sysctl.c index f35a1990456e..88f92eff7bf2 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1831,7 +1831,7 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = &zero, - .extra2 = &one, + .extra2 = &three, }, #endif { diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ad416016d1e9..7fbc9c214da9 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -63,11 +63,14 @@ #include "internal.h" #include "ras/ras_event.h" +#define SOFT_OFFLINE_ENABLED BIT(0) +#define SOFT_OFFLINE_SKIP_HUGETLB BIT(1) + int sysctl_memory_failure_early_kill __read_mostly = 0; int sysctl_memory_failure_recovery __read_mostly = 1; -int sysctl_enable_soft_offline __read_mostly = 1; +int sysctl_enable_soft_offline __read_mostly = SOFT_OFFLINE_ENABLED; atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); @@ -2031,13 +2034,22 @@ int soft_offline_page(struct page *page, 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"); if (flags & MF_COUNT_INCREASED) put_page(page); return -EOPNOTSUPP; } + if (sysctl_enable_soft_offline & SOFT_OFFLINE_SKIP_HUGETLB) { + if (PageHuge(page)) { + pr_info_once("disabled for HugeTLB pages by /proc/sys/vm/enable_soft_offline\n"); + if (flags & MF_COUNT_INCREASED) + put_page(page); + return -EOPNOTSUPP; + } + } + if (PageHWPoison(page)) { pr_info("soft offline: %#lx page already poisoned\n", pfn); if (flags & MF_COUNT_INCREASED) -- 2.43.0