diff options
| author | Kiryl Shutsemau <kas@kernel.org> | 2025-09-23 12:07:08 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-28 11:51:30 -0700 |
| commit | 8c49fbafedf15149069cdb9e0d543c4a68a1c683 (patch) | |
| tree | f7068436cb6105fb88c3067905bbcddccaad456f | |
| parent | a2880202767daded2898f62265f6cdf4cfb53bc4 (diff) | |
mm/rmap: mlock large folios in try_to_unmap_one()
Currently, try_to_unmap_once() only tries to mlock small folios.
Use logic similar to folio_referenced_one() to mlock large folios: only do
this for fully mapped folios and under page table lock that protects all
page table entries.
[akpm@linux-foundation.org: s/CROSSSED/CROSSED/]
Link: https://lkml.kernel.org/r/20250923110711.690639-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/rmap.c | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index d174168b8f93..92eeb3866494 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1870,6 +1870,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, unsigned long nr_pages = 1, end_addr; unsigned long pfn; unsigned long hsz = 0; + int ptes = 0; /* * When racing against e.g. zap_pte_range() on another cpu, @@ -1910,10 +1911,34 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, */ if (!(flags & TTU_IGNORE_MLOCK) && (vma->vm_flags & VM_LOCKED)) { + ptes++; + + /* + * Set 'ret' to indicate the page cannot be unmapped. + * + * Do not jump to walk_abort immediately as additional + * iteration might be required to detect fully mapped + * folio an mlock it. + */ + ret = false; + + /* Only mlock fully mapped pages */ + if (pvmw.pte && ptes != pvmw.nr_pages) + continue; + + /* + * All PTEs must be protected by page table lock in + * order to mlock the page. + * + * If page table boundary has been cross, current ptl + * only protect part of ptes. + */ + if (pvmw.flags & PVMW_PGTABLE_CROSSED) + goto walk_done; + /* Restore the mlock which got missed */ - if (!folio_test_large(folio)) - mlock_vma_folio(folio, vma); - goto walk_abort; + mlock_vma_folio(folio, vma); + goto walk_done; } if (!pvmw.pte) { |