The quilt patch titled
Subject: mm/rmap: fail try_to_migrate() early when setting a PMD migration entry fails
has been removed from the -mm tree. Its filename was
mm-rmap-fail-try_to_migrate-early-when-setting-a-pmd-migration-entry-fails.patch
This patch was dropped because it was merged into mm-stable
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/rmap: fail try_to_migrate() early when setting a PMD migration entry fails
Let's fail right away in case we cannot clear PG_anon_exclusive because
the anon THP may be pinned. Right now, we continue trying to install
migration entries and the caller of try_to_migrate() will realize that the
page is still mapped and has to restore the migration entries. Let's just
fail fast just like for PTE migration entries.
Link: https://lkml.kernel.org/r/20220428083441.37290-14-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Don Dutile <ddutile@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Liang Zhang <zhangliang5@xxxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Nadav Amit <namit@xxxxxxxxxx>
Cc: Oded Gabbay <oded.gabbay@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pedro Demarchi Gomes <pedrodemargomes@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swapops.h | 4 ++--
mm/huge_memory.c | 8 +++++---
mm/rmap.c | 6 +++++-
3 files changed, 12 insertions(+), 6 deletions(-)
--- a/include/linux/swapops.h~mm-rmap-fail-try_to_migrate-early-when-setting-a-pmd-migration-entry-fails
+++ a/include/linux/swapops.h
@@ -299,7 +299,7 @@ static inline bool is_pfn_swap_entry(swp
struct page_vma_mapped_walk;
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
-extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
+extern int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page);
extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
@@ -332,7 +332,7 @@ static inline int is_pmd_migration_entry
return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
}
#else
-static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
+static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page)
{
BUILD_BUG();
--- a/mm/huge_memory.c~mm-rmap-fail-try_to_migrate-early-when-setting-a-pmd-migration-entry-fails
+++ a/mm/huge_memory.c
@@ -3071,7 +3071,7 @@ late_initcall(split_huge_pages_debugfs);
#endif
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
-void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
+int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page)
{
struct vm_area_struct *vma = pvmw->vma;
@@ -3083,7 +3083,7 @@ void set_pmd_migration_entry(struct page
pmd_t pmdswp;
if (!(pvmw->pmd && !pvmw->pte))
- return;
+ return 0;
flush_cache_range(vma, address, address + HPAGE_PMD_SIZE);
pmdval = pmdp_invalidate(vma, address, pvmw->pmd);
@@ -3091,7 +3091,7 @@ void set_pmd_migration_entry(struct page
anon_exclusive = PageAnon(page) && PageAnonExclusive(page);
if (anon_exclusive && page_try_share_anon_rmap(page)) {
set_pmd_at(mm, address, pvmw->pmd, pmdval);
- return;
+ return -EBUSY;
}
if (pmd_dirty(pmdval))
@@ -3109,6 +3109,8 @@ void set_pmd_migration_entry(struct page
page_remove_rmap(page, vma, true);
put_page(page);
trace_set_migration_pmd(address, pmd_val(pmdswp));
+
+ return 0;
}
void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
--- a/mm/rmap.c~mm-rmap-fail-try_to_migrate-early-when-setting-a-pmd-migration-entry-fails
+++ a/mm/rmap.c
@@ -1856,7 +1856,11 @@ static bool try_to_migrate_one(struct fo
VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) ||
!folio_test_pmd_mappable(folio), folio);
- set_pmd_migration_entry(&pvmw, subpage);
+ if (set_pmd_migration_entry(&pvmw, subpage)) {
+ ret = false;
+ page_vma_mapped_walk_done(&pvmw);
+ break;
+ }
continue;
}
#endif
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
