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>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 2ff4ba7..af7fb23 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;
}