On 11/27/2024 1:51 PM, Gregory Price wrote:
To migrate unmapped pagecache folios, migrate_misplaced_folio and migrate_misplaced_folio_prepare must handle folios without VMAs. migrate_misplaced_folio_prepare checks VMA for exec bits, so allow a NULL VMA when it does not have a mapping. migrate_misplaced_folio must call migrate_pages with MIGRATE_SYNC when in the pagecache path because it is a synchronous context. Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Gregory Price <gourry@xxxxxxxxxx> --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index dfb5eba3c522..3b0bd3f21ac3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2632,7 +2632,7 @@ int migrate_misplaced_folio_prepare(struct folio *folio, * See folio_likely_mapped_shared() on possible imprecision * when we cannot easily detect if a folio is shared. */ - if ((vma->vm_flags & VM_EXEC) && + if (vma && (vma->vm_flags & VM_EXEC) && folio_likely_mapped_shared(folio)) return -EACCES;
Thanks for this patch. This would be helpful in the cases of independent page scanning algorithms where we do not have a VMA associated with that. Hopefully it can be taken to tree independently. Feel free to add. Reviewed-by: Raghavendra K T <raghavendra.kt@xxxxxxx>
