mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage
Patch series "mm, hwpoison: improve handling workload related to hugetlb
and memory_hotplug", v7.
This patchset tries to solve the issue among memory_hotplug, hugetlb and hwpoison.
In this patchset, memory hotplug handles hwpoison pages like below:
- hwpoison pages should not prevent memory hotremove,
- memory block with hwpoison pages should not be onlined.
This patch (of 4):
HWPoisoned page is not supposed to be accessed once marked, but currently
such accesses can happen during memory hotremove because
do_migrate_range() can be called before dissolve_free_huge_pages() is
called.
Clear HPageMigratable for hwpoisoned hugepages to prevent them from being
migrated. This should be done in hugetlb_lock to avoid race against
isolate_hugetlb().
get_hwpoison_huge_page() needs to have a flag to show it's called from
unpoison to take refcount of hwpoisoned hugepages, so add it.
[naoya.horiguchi@linux.dev: remove TestClearHPageMigratable and reduce to test and clear separately]
Link: https://lkml.kernel.org/r/20221025053559.GA2104800@ik1-406-35019.vs.sakura.ne.jp
Link: https://lkml.kernel.org/r/20221024062012.1520887-1-naoya.horiguchi@linux.dev
Link: https://lkml.kernel.org/r/20221024062012.1520887-2-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1359455..4fff0b3 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1244,7 +1244,7 @@ static int __get_hwpoison_page(struct page *page, unsigned long flags)
int ret = 0;
bool hugetlb = false;
- ret = get_hwpoison_huge_page(head, &hugetlb);
+ ret = get_hwpoison_huge_page(head, &hugetlb, false);
if (hugetlb)
return ret;
@@ -1334,7 +1334,7 @@ static int __get_unpoison_page(struct page *page)
int ret = 0;
bool hugetlb = false;
- ret = get_hwpoison_huge_page(head, &hugetlb);
+ ret = get_hwpoison_huge_page(head, &hugetlb, true);
if (hugetlb)
return ret;
@@ -1785,7 +1785,8 @@ void hugetlb_clear_page_hwpoison(struct page *hpage)
* -EBUSY - the hugepage is busy (try to retry)
* -EHWPOISON - the hugepage is already hwpoisoned
*/
-int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+ bool *migratable_cleared)
{
struct page *page = pfn_to_page(pfn);
struct page *head = compound_head(page);
@@ -1815,6 +1816,15 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
goto out;
}
+ /*
+ * Clearing HPageMigratable for hwpoisoned hugepages to prevent them
+ * from being migrated by memory hotremove.
+ */
+ if (count_increased && HPageMigratable(head)) {
+ ClearHPageMigratable(head);
+ *migratable_cleared = true;
+ }
+
return ret;
out:
if (count_increased)
@@ -1834,10 +1844,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
struct page *p = pfn_to_page(pfn);
struct page *head;
unsigned long page_flags;
+ bool migratable_cleared = false;
*hugetlb = 1;
retry:
- res = get_huge_page_for_hwpoison(pfn, flags);
+ res = get_huge_page_for_hwpoison(pfn, flags, &migratable_cleared);
if (res == 2) { /* fallback to normal page handling */
*hugetlb = 0;
return 0;
@@ -1861,6 +1872,8 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
if (hwpoison_filter(p)) {
hugetlb_clear_page_hwpoison(head);
+ if (migratable_cleared)
+ SetHPageMigratable(head);
unlock_page(head);
if (res == 1)
put_page(head);
