From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Subject: mm,hwpoison: cleanup unused PageHuge() check Patch series "HWPOISON: soft offline rework", v7. This patchset fixes a couple of issues that the patchset Naoya sent [1] contained due to rebasing problems and a misunterdansting. Main focus of this series is to stabilize soft offline. Historically soft offlined pages have suffered from racy conditions because PageHWPoison is used to a little too aggressively, which (directly or indirectly) invades other mm code which cares little about hwpoison. This results in unexpected behavior or kernel panic, which is very far from soft offline's "do not disturb userspace or other kernel component" policy. An example of this can be found here [2]. Along with several cleanups, this code refactors and changes the way soft offline work. Main point of this change set is to contain target page "via buddy allocator" or in migrating path. For ther former we first free the target page as we do for normal pages, and once it has reached buddy and it has been taken off the freelists, we flag it as HWpoison. For the latter we never get to release the page in unmap_and_move, so the page is under our control and we can handle it in hwpoison code. [1] https://patchwork.kernel.org/cover/11704083/ [2] https://lore.kernel.org/linux-mm/20190826104144.GA7849@linux/T/#u This patch (of 14): Drop the PageHuge check, which is dead code since memory_failure() forks into memory_failure_hugetlb() for hugetlb pages. memory_failure() and memory_failure_hugetlb() shares some functions like hwpoison_user_mappings() and identify_page_state(), so they should properly handle 4kB page, thp, and hugetlb. Link: https://lkml.kernel.org/r/20200922135650.1634-1-osalvador@xxxxxxx Link: https://lkml.kernel.org/r/20200922135650.1634-2-osalvador@xxxxxxx Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> Cc: Aristeu Rozanski <aris@xxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory-failure.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- a/mm/memory-failure.c~mmhwpoison-cleanup-unused-pagehuge-check +++ a/mm/memory-failure.c @@ -1381,10 +1381,7 @@ int memory_failure(unsigned long pfn, in * page_remove_rmap() in try_to_unmap_one(). So to determine page status * correctly, we save a copy of the page flags at this time. */ - if (PageHuge(p)) - page_flags = hpage->flags; - else - page_flags = p->flags; + page_flags = p->flags; /* * unpoison always clear PG_hwpoison inside page lock _
