From: Kefeng Wang wangkefeng.wang@huawei.com
mainline inclusion from mainline-v6.7-rc1 commit a8ac4a767dcd9d87d8229045904d9fe15ea5e0e8 category: other bugzilla: https://gitee.com/openeuler/kernel/issues/I8JQWQ
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Patch series "mm: migrate: more folio conversion and unification", v3.
Convert more migrate functions to use a folio, it is also a preparation for large folio migration support when balancing numa.
This patch (of 8):
The assert VM_BUG_ON_PAGE(order && !PageTransHuge(page), page) is not very useful,
1) for a tail/base page, order = 0, for a head page, the order > 0 && PageTransHuge() is true 2) there is a PageCompound() check and only base page is handled in do_numa_page(), and do_huge_pmd_numa_page() only handle PMD-mapped THP 3) even though the page is a tail page, isolate_lru_page() will post a warning, and fail to isolate the page 4) if large folio/pte-mapped THP migration supported in the future, we could migrate the entire folio if numa fault on a tail page
so just remove the check.
Link: https://lkml.kernel.org/r/20230913095131.2426871-1-wangkefeng.wang@huawei.co... Link: https://lkml.kernel.org/r/20230913095131.2426871-2-wangkefeng.wang@huawei.co... Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Suggested-by: Matthew Wilcox (Oracle) willy@infradead.org Cc: David Hildenbrand david@redhat.com Cc: Huang Ying ying.huang@intel.com Cc: Hugh Dickins hughd@google.com Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Zi Yan ziy@nvidia.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- mm/migrate.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c index 06086dc9da28..d19885a0f908 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2496,8 +2496,6 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) int nr_pages = thp_nr_pages(page); int order = compound_order(page);
- VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); - /* Do not migrate THP mapped by multiple processes */ if (PageTransHuge(page) && total_mapcount(page) > 1) return 0;