take_page_off_buddy will be used to take a page meant to be poisoned off the buddy allocator. take_page_off_buddy calls break_down_buddy_pages, which will split a higher-order page in case our page belongs to one.
Once we grab the page, we call page_set_poison to set it as poisoned and grab a refcount on it. Signed-off-by: Oscar Salvador <[email protected]> --- include/linux/page-flags.h | 5 ---- mm/memory-failure.c | 6 +++-- mm/page_alloc.c | 59 +++++++++++++++++++++++++++++++++++++++------- 3 files changed, 54 insertions(+), 16 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index f91cb8898ff0..21df81c9ea57 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -414,13 +414,8 @@ PAGEFLAG_FALSE(Uncached) PAGEFLAG(HWPoison, hwpoison, PF_ANY) TESTSCFLAG(HWPoison, hwpoison, PF_ANY) #define __PG_HWPOISON (1UL << PG_hwpoison) -extern bool set_hwpoison_free_buddy_page(struct page *page); #else PAGEFLAG_FALSE(HWPoison) -static inline bool set_hwpoison_free_buddy_page(struct page *page) -{ - return 0; -} #define __PG_HWPOISON 0 #endif diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ce017a0d79a6..03f07015a106 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -78,6 +78,8 @@ EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); +extern bool take_page_off_buddy(struct page *page); + static bool page_set_poison(struct page *page) { SetPageHWPoison(page); @@ -1807,8 +1809,8 @@ static int soft_offline_free_page(struct page *page) int rc = dissolve_free_huge_page(page); if (!rc) { - if (set_hwpoison_free_buddy_page(page)) - num_poisoned_pages_inc(); + if (take_page_off_buddy(page)) + page_set_poison(page); else rc = -EBUSY; } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index fe38229d0a77..68f6c2cda512 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8605,30 +8605,71 @@ bool is_free_buddy_page(struct page *page) #ifdef CONFIG_MEMORY_FAILURE /* - * Set PG_hwpoison flag if a given page is confirmed to be a free page. This - * test is performed under the zone lock to prevent a race against page - * allocation. + * Break down a higher-order page in sub-pages, and keep our target out of + * buddy allocator. */ -bool set_hwpoison_free_buddy_page(struct page *page) +static void break_down_buddy_pages(struct zone *zone, struct page *page, + struct page *target, int low, int high, + struct free_area *area, int migratetype) +{ + unsigned long size = 1 << high; + struct page *current_buddy, *next_page; + + while (high > low) { + area--; + high--; + size >>= 1; + + if (target >= &page[size]) { + next_page = page + size; + current_buddy = page; + } else { + next_page = page; + current_buddy = page + size; + } + + if (set_page_guard(zone, current_buddy, high, migratetype)) + continue; + + if (current_buddy != target) { + add_to_free_area(current_buddy, area, migratetype); + set_page_order(current_buddy, high); + page = next_page; + } + } +} + +/* + * Take a page that will be marked as poisoned off the buddy allocator. + */ +bool take_page_off_buddy(struct page *page) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); unsigned long flags; unsigned int order; - bool hwpoisoned = false; + bool ret = false; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { struct page *page_head = page - (pfn & ((1 << order) - 1)); + int buddy_order = page_order(page_head); + struct free_area *area = &(zone->free_area[buddy_order]); + + if (PageBuddy(page_head) && buddy_order >= order) { + unsigned long pfn_head = page_to_pfn(page_head); + int migratetype = get_pfnblock_migratetype(page_head, + pfn_head); - if (PageBuddy(page_head) && page_order(page_head) >= order) { - if (!TestSetPageHWPoison(page)) - hwpoisoned = true; + del_page_from_free_area(page_head, area); + break_down_buddy_pages(zone, page_head, page, 0, + buddy_order, area, migratetype); + ret = true; break; } } spin_unlock_irqrestore(&zone->lock, flags); - return hwpoisoned; + return ret; } #endif -- 2.12.3
