diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-memory-page-offline | 44 | ||||
| -rw-r--r-- | drivers/base/memory.c | 61 | ||||
| -rw-r--r-- | include/linux/mm.h | 3 | ||||
| -rw-r--r-- | mm/hwpoison-inject.c | 2 | ||||
| -rw-r--r-- | mm/memory-failure.c | 194 |
5 files changed, 297 insertions, 7 deletions
diff --git a/Documentation/ABI/testing/sysfs-memory-page-offline b/Documentation/ABI/testing/sysfs-memory-page-offline new file mode 100644 index 0000000..e14703f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-memory-page-offline @@ -0,0 +1,44 @@ +What: /sys/devices/system/memory/soft_offline_page +Date: Sep 2009 +KernelVersion: 2.6.33 +Contact: andi@firstfloor.org +Description: + Soft-offline the memory page containing the physical address + written into this file. Input is a hex number specifying the + physical address of the page. The kernel will then attempt + to soft-offline it, by moving the contents elsewhere or + dropping it if possible. The kernel will then be placed + on the bad page list and never be reused. + + The offlining is done in kernel specific granuality. + Normally it's the base page size of the kernel, but + this might change. + + The page must be still accessible, not poisoned. The + kernel will never kill anything for this, but rather + fail the offline. Return value is the size of the + number, or a error when the offlining failed. Reading + the file is not allowed. + +What: /sys/devices/system/memory/hard_offline_page +Date: Sep 2009 +KernelVersion: 2.6.33 +Contact: andi@firstfloor.org +Description: + Hard-offline the memory page containing the physical + address written into this file. Input is a hex number + specifying the physical address of the page. The + kernel will then attempt to hard-offline the page, by + trying to drop the page or killing any owner or + triggering IO errors if needed. Note this may kill + any processes owning the page. The kernel will avoid + to access this page assuming it's poisoned by the + hardware. + + The offlining is done in kernel specific granuality. + Normally it's the base page size of the kernel, but + this might change. + + Return value is the size of the number, or a error when + the offlining failed. + Reading the file is not allowed. diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 989429c..c4c8f2e 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -341,6 +341,64 @@ static inline int memory_probe_init(void) } #endif +#ifdef CONFIG_MEMORY_FAILURE +/* + * Support for offlining pages of memory + */ + +/* Soft offline a page */ +static ssize_t +store_soft_offline_page(struct class *class, const char *buf, size_t count) +{ + int ret; + u64 pfn; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (strict_strtoull(buf, 0, &pfn) < 0) + return -EINVAL; + pfn >>= PAGE_SHIFT; + if (!pfn_valid(pfn)) + return -ENXIO; + ret = soft_offline_page(pfn_to_page(pfn), 0); + return ret == 0 ? count : ret; +} + +/* Forcibly offline a page, including killing processes. */ +static ssize_t +store_hard_offline_page(struct class *class, const char *buf, size_t count) +{ + int ret; + u64 pfn; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (strict_strtoull(buf, 0, &pfn) < 0) + return -EINVAL; + pfn >>= PAGE_SHIFT; + ret = __memory_failure(pfn, 0, 0); + return ret ? ret : count; +} + +static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page); +static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page); + +static __init int memory_fail_init(void) +{ + int err; + + err = sysfs_create_file(&memory_sysdev_class.kset.kobj, + &class_attr_soft_offline_page.attr); + if (!err) + err = sysfs_create_file(&memory_sysdev_class.kset.kobj, + &class_attr_hard_offline_page.attr); + return err; +} +#else +static inline int memory_fail_init(void) +{ + return 0; +} +#endif + /* * Note that phys_device is optional. It is here to allow for * differentiation between which *physical* devices each @@ -473,6 +531,9 @@ int __init memory_dev_init(void) err = memory_probe_init(); if (!ret) ret = err; + err = memory_fail_init(); + if (!ret) + ret = err; err = block_size_init(); if (!ret) ret = err; diff --git a/include/linux/mm.h b/include/linux/mm.h index 8cdb941..849b4a6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1339,8 +1339,9 @@ extern int __memory_failure(unsigned long pfn, int trapno, int flags); extern int unpoison_memory(unsigned long pfn); extern int sysctl_memory_failure_early_kill; extern int sysctl_memory_failure_recovery; -extern void shake_page(struct page *p); +extern void shake_page(struct page *p, int access); extern atomic_long_t mce_bad_pages; +extern int soft_offline_page(struct page *page, int flags); #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c index c597f46..a77fe3f 100644 --- a/mm/hwpoison-inject.c +++ b/mm/hwpoison-inject.c @@ -29,7 +29,7 @@ static int hwpoison_inject(void *data, u64 val) return 0; if (!PageLRU(p)) - shake_page(p); + shake_page(p, 0); /* * This implies unable to support non-LRU pages. */ diff --git a/mm/memory-failure.c b/mm/memory-failure.c index b5c3b6b..bcce287 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -41,6 +41,9 @@ #include <linux/pagemap.h> #include <linux/swap.h> #include <linux/backing-dev.h> +#include <linux/migrate.h> +#include <linux/page-isolation.h> +#include <linux/suspend.h> #include "internal.h" int sysctl_memory_failure_early_kill __read_mostly = 0; @@ -201,7 +204,7 @@ static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno, * When a unknown page type is encountered drain as many buffers as possible * in the hope to turn the page into a LRU or free page, which we can handle. */ -void shake_page(struct page *p) +void shake_page(struct page *p, int access) { if (!PageSlab(p)) { lru_add_drain_all(); @@ -211,11 +214,19 @@ void shake_page(struct page *p) if (PageLRU(p) || is_free_buddy_page(p)) return; } + /* - * Could call shrink_slab here (which would also - * shrink other caches). Unfortunately that might - * also access the corrupted page, which could be fatal. + * Only all shrink_slab here (which would also + * shrink other caches) if access is not potentially fatal. */ + if (access) { + int nr; + do { + nr = shrink_slab(1000, GFP_KERNEL, 1000); + if (page_count(p) == 0) + break; + } while (nr > 10); + } } EXPORT_SYMBOL_GPL(shake_page); @@ -949,7 +960,7 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) * walked by the page reclaim code, however that's not a big loss. */ if (!PageLRU(p)) - shake_page(p); + shake_page(p, 0); if (!PageLRU(p)) { /* * shake_page could have turned it free. @@ -1099,3 +1110,176 @@ int unpoison_memory(unsigned long pfn) return 0; } EXPORT_SYMBOL(unpoison_memory); + +static struct page *new_page(struct page *p, unsigned long private, int **x) +{ + return alloc_pages(GFP_HIGHUSER_MOVABLE, 0); +} + +/* + * Safely get reference count of an arbitrary page. + * Returns 0 for a free page, -EIO for a zero refcount page + * that is not free, and 1 for any other page type. + * For 1 the page is returned with increased page count, otherwise not. + */ +static int get_any_page(struct page *p, unsigned long pfn, int flags) +{ + int ret; + + if (flags & MF_COUNT_INCREASED) + return 1; + + /* + * The lock_system_sleep prevents a race with memory hotplug, + * because the isolation assumes there's only a single user. + * This is a big hammer, a better would be nicer. + */ + lock_system_sleep(); + + /* + * Isolate the page, so that it doesn't get reallocated if it + * was free. + */ + set_migratetype_isolate(p); + if (!get_page_unless_zero(compound_head(p))) { + if (is_free_buddy_page(p)) { + pr_debug("get_any_page: %#lx free buddy page\n", pfn); + /* Set hwpoison bit while page is still isolated */ + SetPageHWPoison(p); + ret = 0; + } else { + pr_debug("get_any_page: %#lx: unknown zero refcount page type %lx\n", + pfn, p->flags); + ret = -EIO; + } + } else { + /* Not a free page */ + ret = 1; + } + unset_migratetype_isolate(p); + unlock_system_sleep(); + return ret; +} + +/** + * soft_offline_page - Soft offline a page. + * @page: page to offline + * @flags: flags. Same as memory_failure(). + * + * Returns 0 on success, otherwise negated errno. + * + * Soft offline a page, by migration or invalidation, + * without killing anything. This is for the case when + * a page is not corrupted yet (so it's still valid to access), + * but has had a number of corrected errors and is better taken + * out. + * + * The actual policy on when to do that is maintained by + * user space. + * + * This should never impact any application or cause data loss, + * however it might take some time. + * + * This is not a 100% solution for all memory, but tries to be + * ``good enough'' for the majority of memory. + */ +int soft_offline_page(struct page *page, int flags) +{ + int ret; + unsigned long pfn = page_to_pfn(page); + + ret = get_any_page(page, pfn, flags); + if (ret < 0) + return ret; + if (ret == 0) + goto done; + + /* + * Page cache page we can handle? + */ + if (!PageLRU(page)) { + /* + * Try to free it. + */ + put_page(page); + shake_page(page, 1); + + /* + * Did it turn free? + */ + ret = get_any_page(page, pfn, 0); + if (ret < 0) + return ret; + if (ret == 0) + goto done; + } + if (!PageLRU(page)) { + pr_debug("soft_offline: %#lx: unknown non LRU page type %lx\n", + pfn, page->flags); + return -EIO; + } + + lock_page(page); + wait_on_page_writeback(page); + + /* + * Synchronized using the page lock with memory_failure() + */ + if (PageHWPoison(page)) { + unlock_page(page); + put_page(page); + pr_debug("soft offline: %#lx page already poisoned\n", pfn); + return -EBUSY; + } + + /* + * Try to invalidate first. This should work for + * non dirty unmapped page cache pages. + */ + ret = invalidate_inode_page(page); + unlock_page(page); + + /* + * Drop count because page migration doesn't like raised + * counts. The page could get re-allocated, but if it becomes + * LRU the isolation will just fail. + * RED-PEN would be better to keep it isolated here, but we + * would need to fix isolation locking first. + */ + put_page(page); + if (ret == 1) { + ret = 0; + pr_debug("soft_offline: %#lx: invalidated\n", pfn); + goto done; + } + + /* + * Simple invalidation didn't work. + * Try to migrate to a new page instead. migrate.c + * handles a large number of cases for us. + */ + ret = isolate_lru_page(page); + if (!ret) { + LIST_HEAD(pagelist); + + list_add(&page->lru, &pagelist); + ret = migrate_pages(&pagelist, new_page, MPOL_MF_MOVE_ALL, 0); + if (ret) { + pr_debug("soft offline: %#lx: migration failed %d, type %lx\n", + pfn, ret, page->flags); + if (ret > 0) + ret = -EIO; + } + } else { + pr_debug("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n", + pfn, ret, page_count(page), page->flags); + } + if (ret) + return ret; + +done: + atomic_long_add(1, &mce_bad_pages); + SetPageHWPoison(page); + /* keep elevated page count for bad page */ + return ret; +} |
