diff options
Diffstat (limited to 'mm/memory-failure.c')
| -rw-r--r-- | mm/memory-failure.c | 194 |
1 files changed, 189 insertions, 5 deletions
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; +} |
