On 2024/7/31 14:18, Barry Song wrote:
On Wed, Jul 31, 2024 at 1:46 PM Baolin Wang
<baolin.wang@xxxxxxxxxxxxxxxxx> wrote:
Similar to commit d659b715e94ac ("mm/huge_memory: avoid PMD-size page cache
if needed"), ARM64 can support 512MB PMD-sized THP when the base page size is
64KB, which is larger than the maximum supported page cache size MAX_PAGECACHE_ORDER.
This is not expected. To fix this issue, use THP_ORDERS_ALL_FILE_DEFAULT for
shmem to filter allowable huge orders.
Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
Thanks for reviewing.
---
mm/shmem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 2faa9daaf54b..a4332a97558c 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1630,10 +1630,10 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size);
unsigned long vm_flags = vma->vm_flags;
/*
- * Check all the (large) orders below HPAGE_PMD_ORDER + 1 that
+ * Check all the (large) orders below MAX_PAGECACHE_ORDER + 1 that
* are enabled for this vma.
Nit:
THP_ORDERS_ALL_FILE_DEFAULT should be self-explanatory enough.
I feel we don't need this comment?
Sure.
Andrew, please help to squash the following changes into this patch. Thanks.
diff --git a/mm/shmem.c b/mm/shmem.c
index 6e9836b1bd1d..432faec21547 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1629,10 +1629,6 @@ unsigned long shmem_allowable_huge_orders(struct
inode *inode,
unsigned long mask = READ_ONCE(huge_shmem_orders_always);
unsigned long within_size_orders =
READ_ONCE(huge_shmem_orders_within_size);
unsigned long vm_flags = vma->vm_flags;
- /*
- * Check all the (large) orders below MAX_PAGECACHE_ORDER + 1 that
- * are enabled for this vma.
- */
unsigned long orders = THP_ORDERS_ALL_FILE_DEFAULT;
loff_t i_size;
int order;
