Messages in this thread | | | Date | Mon, 21 Aug 2023 22:41:21 +0800 | Subject | Re: [PATCH v2 1/8] mm: migrate: remove PageTransHuge check in numamigrate_isolate_page() | From | Kefeng Wang <> |
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On 2023/8/21 20:52, Kefeng Wang wrote: > > > On 2023/8/21 20:38, Matthew Wilcox wrote: >> On Mon, Aug 21, 2023 at 07:56:17PM +0800, Kefeng Wang wrote: >>> Since we begin to convert the numa migration code to use folio, which >>> could let us to handle arbitrary sizes of folio, so drop assert that >>> we only support PageTransHuge page(PMD size) when order > 0. >> >> Have you looked at the implementation of PageTransHuge()? Your >> description doesn't match what the code does. > > oops, not only PMD size...
Please ignore about reply, sorry,I misread, PageTransHuge return true for head page, and BUG_ON for tail page, and compound_order(page) will return 0 for tail page, so when begin to convert page to folio, we could drop this line since it is not useful check for folio.
> >> >>> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> >>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >>> --- >>> mm/migrate.c | 2 -- >>> 1 file changed, 2 deletions(-) >>> >>> diff --git a/mm/migrate.c b/mm/migrate.c >>> index b7fa020003f3..646d8ee7f102 100644 >>> --- a/mm/migrate.c >>> +++ b/mm/migrate.c >>> @@ -2483,8 +2483,6 @@ 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; >>> -- >>> 2.41.0 >>> >>> >>
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