From: Oscar Salvador <osalvador@xxxxxxx>
Subject: mm,hwpoison: return 0 if the page is already poisoned in soft-offline
Currently, there is an inconsistency when calling soft-offline from
different paths on a page that is already poisoned.
1) madvise:
madvise_inject_error skips any poisoned page and continues
the loop.
If that was the only page to madvise, it returns 0.
2) /sys/devices/system/memory/:
When calling soft_offline_page_store()->soft_offline_page(),
we return -EBUSY in case the page is already poisoned.
This is inconsistent with a) the above example and b)
memory_failure, where we return 0 if the page was poisoned.
Fix this by dropping the PageHWPoison() check in madvise_inject_error, and
let soft_offline_page return 0 if it finds the page already poisoned.
Please, note that this represents a user-api change, since now the return
error when calling soft_offline_page_store()->soft_offline_page() will be
different.
Link: https://lkml.kernel.org/r/20200922135650.1634-12-osalvador@xxxxxxx
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Aristeu Rozanski <aris@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/madvise.c | 5 -----
mm/memory-failure.c | 4 ++--
2 files changed, 2 insertions(+), 7 deletions(-)
--- a/mm/madvise.c~mmhwpoison-return-0-if-the-page-is-already-poisoned-in-soft-offline
+++ a/mm/madvise.c
@@ -896,11 +896,6 @@ static int madvise_inject_error(int beha
*/
size = page_size(compound_head(page));
- if (PageHWPoison(page)) {
- put_page(page);
- continue;
- }
-
if (behavior == MADV_SOFT_OFFLINE) {
pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
pfn, start);
--- a/mm/memory-failure.c~mmhwpoison-return-0-if-the-page-is-already-poisoned-in-soft-offline
+++ a/mm/memory-failure.c
@@ -1802,7 +1802,7 @@ static int __soft_offline_page(struct pa
unlock_page(page);
put_page(page);
pr_info("soft offline: %#lx page already poisoned\n", pfn);
- return -EBUSY;
+ return 0;
}
if (!PageHuge(page))
@@ -1906,7 +1906,7 @@ int soft_offline_page(unsigned long pfn,
pr_info("soft offline: %#lx page already poisoned\n", pfn);
if (flags & MF_COUNT_INCREASED)
put_page(page);
- return -EBUSY;
+ return 0;
}
get_online_mems();
_
