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Huang Ying authored
This is a preparation patch to batch the folio unmapping and moving for non-hugetlb folios. If we had batched the folio unmapping, all folios to be migrated would be unmapped before copying the contents and flags of the folios. If the folios that were passed to migrate_pages() were too many in unit of pages, the execution of the processes would be stopped for too long time, thus too long latency. For example, migrate_pages() syscall will call migrate_pages() with all folios of a process. To avoid this possible issue, in this patch, we restrict the number of pages to be migrated to be no more than HPAGE_PMD_NR. That is, the influence is at the same level of THP migration. Link: https://lkml.kernel.org/r/20230213123444.155149-4-ying.huang@intel.comSigned-off-by:
"Huang, Ying" <ying.huang@intel.com> Reviewed-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Bharata B Rao <bharata@amd.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Xin Hao <xhao@linux.alibaba.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
42012e04