diff options
author | Oscar Salvador <osalvador@suse.de> | 2020-10-16 06:07:05 +0300 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-16 21:11:16 +0300 |
commit | 06be6ff3d2ec8be806b859fc054a1909b16d2473 (patch) | |
tree | e679355cd59c86024cbcfca207fc089f9800cc1e | |
parent | 694bf0b0cdf91be50e6f037ca93733ed83ca1187 (diff) | |
download | linux-06be6ff3d2ec8be806b859fc054a1909b16d2473.tar.xz |
mm,hwpoison: rework soft offline for free pages
When trying to soft-offline a free page, we need to first take it off the
buddy allocator. Once we know is out of reach, we can safely flag it as
poisoned.
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 splits a higher-order page in case our page belongs to one.
Once the page is under our control, we call page_handle_poison to set it
as poisoned and grab a refcount on it.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-9-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/linux/page-flags.h | 1 | ||||
-rw-r--r-- | mm/memory-failure.c | 18 | ||||
-rw-r--r-- | mm/page_alloc.c | 68 |
3 files changed, 81 insertions, 6 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 38ded408bd4c..a02b6d0221db 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -432,6 +432,7 @@ 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); +extern bool take_page_off_buddy(struct page *page); #else PAGEFLAG_FALSE(HWPoison) static inline bool set_hwpoison_free_buddy_page(struct page *page) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 2ff4ba7fa99f..af7fb23b93ae 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -65,6 +65,13 @@ int sysctl_memory_failure_recovery __read_mostly = 1; atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); +static void page_handle_poison(struct page *page) +{ + SetPageHWPoison(page); + page_ref_inc(page); + num_poisoned_pages_inc(); +} + #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) u32 hwpoison_filter_enable = 0; @@ -1884,14 +1891,13 @@ static int soft_offline_in_use_page(struct page *page, int flags) static int soft_offline_free_page(struct page *page) { - int rc = dissolve_free_huge_page(page); + int rc = -EBUSY; - if (!rc) { - if (set_hwpoison_free_buddy_page(page)) - num_poisoned_pages_inc(); - else - rc = -EBUSY; + if (!dissolve_free_huge_page(page) && take_page_off_buddy(page)) { + page_handle_poison(page); + rc = 0; } + return rc; } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index febb2d731f9e..12dcfb3dc588 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8778,6 +8778,74 @@ bool is_free_buddy_page(struct page *page) #ifdef CONFIG_MEMORY_FAILURE /* + * Break down a higher-order page in sub-pages, and keep our target out of + * buddy allocator. + */ +static void break_down_buddy_pages(struct zone *zone, struct page *page, + struct page *target, int low, int high, + int migratetype) +{ + unsigned long size = 1 << high; + struct page *current_buddy, *next_page; + + while (high > low) { + 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_list(current_buddy, zone, high, 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 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); + + 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); + + del_page_from_free_list(page_head, zone, buddy_order); + break_down_buddy_pages(zone, page_head, page, 0, + buddy_order, migratetype); + ret = true; + break; + } + if (page_count(page_head) > 0) + break; + } + spin_unlock_irqrestore(&zone->lock, flags); + return ret; +} + +/* * 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. |