From: Baolin Wang <baolin.wang@linux.alibaba.com> mainline inclusion from mainline-v6.11-rc2 commit 4cbf320b1500fe64fcef8c96ed74dfc1ae2c9e2c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAIHPC Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- In the shmem_suitable_orders() function, xa_find() is used to check for conflicts in the pagecache to select suitable huge orders. However, when checking each huge order in every loop, the aligned index is calculated from the previous iteration, which may cause suitable huge orders to be missed. We should use the original index each time in the loop to calculate a new aligned index for checking conflicts to avoid this issue. Link: https://lkml.kernel.org/r/07433b0f16a152bffb8cee34934a5c040e8e2ad6.172240407... Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem") Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Barry Song <21cnbao@gmail.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> Cc: Barry Song <baohua@kernel.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/shmem.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 372112c4f8de..6e773cd8ee66 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1698,6 +1698,7 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault unsigned long orders) { struct vm_area_struct *vma = vmf->vma; + pgoff_t aligned_index; unsigned long pages; int order; @@ -1709,9 +1710,9 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault order = highest_order(orders); while (orders) { pages = 1UL << order; - index = round_down(index, pages); - if (!xa_find(&mapping->i_pages, &index, - index + pages - 1, XA_PRESENT)) + aligned_index = round_down(index, pages); + if (!xa_find(&mapping->i_pages, &aligned_index, + aligned_index + pages - 1, XA_PRESENT)) break; order = next_order(&orders, order); } -- 2.25.1