On Tue, May 13, 2025 at 04:05:21PM +0800, Huacai Chen wrote:
From: Zi Yan ziy@nvidia.com
nr_failed was missing the large folio splits from migrate_pages_batch() and can cause a mismatch between migrate_pages() return value and the number of not migrated pages, i.e., when the return value of migrate_pages() is 0, there are still pages left in the from page list. It will happen when a non-PMD THP large folio fails to migrate due to -ENOMEM and is split successfully but not all the split pages are not migrated, migrate_pages_batch() would return non-zero, but astats.nr_thp_split = 0. nr_failed would be 0 and returned to the caller of migrate_pages(), but the not migrated pages are left in the from page list without being added back to LRU lists.
Fix it by adding a new nr_split counter for large folio splits and adding it to nr_failed in migrate_page_sync() after migrate_pages_batch() is done.
Link: https://lkml.kernel.org/r/20231017163129.2025214-1-zi.yan@sent.com Fixes: 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously firstly") Signed-off-by: Zi Yan ziy@nvidia.com Acked-by: Huang Ying ying.huang@intel.com Reviewed-by: Baolin Wang baolin.wang@linux.alibaba.com Cc: David Hildenbrand david@redhat.com Cc: Matthew Wilcox willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Huacai Chen chenhuacai@loongson.cn
This patch has a Fixes tag and should be backported to 6.6, I don't know why hasn't bakported.
What is the upstream git id for this commit?