[PATCH v2 1/3] mm/huge_memory: skip zone device folios in madvise_free_huge_pmd()
Gregory Price <[email protected]>
| Newsgroups | org.kernel.vger.stable,org.kernel.vger.linux-kernel,org.kvack.linux-mm |
|---|---|
| Message-ID | <[email protected]> |
madvise_free_huge_pmd() resolves the folio backing a PMD via pmd_folio()
and marks it lazyfree without checking for zone device memory.
The surrounding guards do not cover every zone device case:
- MADV_FREE only operates on anonymous VMAs (DAX mappings are excluded)
- !pmd_present() branch rejects device-private and migration entries
- present zone device PMD (device coherent THP) is not filtered.
Unlike vm_normal_page_pmd(), it performs no special/pfnmap check,
and would be marked lazyfree here.
Bail out when the folio is a zone device folio.
Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages")
Cc: [email protected]
Signed-off-by: Gregory Price (Meta) <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Reviewed-by: Lorenzo Stoakes (ARM) <[email protected]>
---
mm/huge_memory.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ced400f72d43a..714773695bbff 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2381,6 +2381,10 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
}
folio = pmd_folio(orig_pmd);
+
+ if (folio_is_zone_device(folio))
+ goto out;
+
/*
* If other processes are mapping this folio, we couldn't discard
* the folio unless they all do MADV_FREE so let's skip the folio.
--
2.53.0-Meta