From b66b1b71d7ff5464d23a0ac6f73fae461b7264fd Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 31 Jul 2024 13:46:19 +0800 Subject: [PATCH] mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem 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: Baolin Wang Signed-off-by: Kefeng Wang Reviewed-by: Barry Song Cc: Barry Song <21cnbao@gmail.com> Cc: David Hildenbrand Cc: Gavin Shan Cc: Hugh Dickins Cc: Lance Yang Cc: Matthew Wilcox Cc: Ryan Roberts Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/shmem.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 2faa9daaf54b..b5be73b04329 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1629,11 +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 HPAGE_PMD_ORDER + 1 that - * are enabled for this vma. - */ - unsigned long orders = BIT(PMD_ORDER + 1) - 1; loff_t i_size; int order; @@ -1678,7 +1673,7 @@ 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,