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mm,hwpoison: rework soft offline for free pages

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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>
This commit is contained in:
Oscar Salvador 2020-10-15 20:07:05 -07:00 committed by Linus Torvalds
parent 694bf0b0cd
commit 06be6ff3d2
3 changed files with 81 additions and 6 deletions
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1
include/linux/page-flags.h
View File

@ -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)

18
mm/memory-failure.c
View File

@ -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;
}

68
mm/page_alloc.c
View File

@ -8777,6 +8777,74 @@ 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