Commit e57297e1 authored by Baolin Wang's avatar Baolin Wang Committed by Liu Shixin
Browse files

mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem 

mainline inclusion
from mainline-v6.11-rc2
commit b66b1b71d7ff5464d23a0ac6f73fae461b7264fd
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAIHPC

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b66b1b71d7ff5464d23a0ac6f73fae461b7264fd

--------------------------------

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.

[baolin.wang@linux.alibaba.com: remove comment, per Barry]
  Link: https://lkml.kernel.org/r/c55d7ef7-78aa-4ed6-b897-c3e03a3f3ab7@linux.alibaba.com
[wangkefeng.wang@huawei.com: remove local `orders']
  Link: https://lkml.kernel.org/r/87769ae8-b6c6-4454-925d-1864364af9c8@huawei.com
Link: https://lkml.kernel.org/r/117121665254442c3c7f585248296495e5e2b45c.1722404078.git.baolin.wang@linux.alibaba.com


Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: default avatarBarry Song <baohua@kernel.org>
Cc: Barry Song <21cnbao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
parent f0caffbf

mm/shmem.c

+1 −6
Original line number Diff line number Diff line
@@ -1646,11 +1646,6 @@ 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 HPAGE_PMD_ORDER + 1 that

	 * are enabled for this vma.

	 */

	unsigned long orders = BIT(PMD_ORDER + 1) - 1;

	loff_t i_size;

	int order;
@@ -1695,7 +1690,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, 
	if (global_huge)

		mask |= READ_ONCE(huge_shmem_orders_inherit);



	return orders & mask;

	return THP_ORDERS_ALL_FILE_DEFAULT & mask;

}



static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault *vmf,