The patch titled
Subject: mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-shmem-avoid-allocating-huge-pages-larger-than-max_pagecache_order-for-shmem.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-avoid-allocating-huge-pages-larger-than-max_pagecache_order-for-shmem.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem
Date: Wed, 31 Jul 2024 13:46:19 +0800
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.
Link: https://lkml.kernel.org/r/117121665254442c3c7f585248296495e5e2b45c.1722404078.git.baolin.wang@xxxxxxxxxxxxxxxxx
Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
Cc: Barry Song <21cnbao@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Gavin Shan <gshan@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/shmem.c~mm-shmem-avoid-allocating-huge-pages-larger-than-max_pagecache_order-for-shmem
+++ a/mm/shmem.c
@@ -1630,10 +1630,10 @@ unsigned long shmem_allowable_huge_order
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.
*/
- unsigned long orders = BIT(PMD_ORDER + 1) - 1;
+ unsigned long orders = THP_ORDERS_ALL_FILE_DEFAULT;
loff_t i_size;
int order;
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-shmem-avoid-allocating-huge-pages-larger-than-max_pagecache_order-for-shmem.patch
mm-shmem-avoid-allocating-huge-pages-larger-than-max_pagecache_order-for-shmem-fix.patch
mm-shmem-fix-incorrect-aligned-index-when-checking-conflicts.patch
mm-shmem-simplify-the-suitable-huge-orders-validation-for-tmpfs.patch
mm-shmem-rename-shmem_is_huge-to-shmem_huge_global_enabled.patch
mm-shmem-move-shmem_huge_global_enabled-into-shmem_allowable_huge_orders.patch
