linux-master/mm/compaction.c

504  * If no pages were isolated then mark this pageblock to be skipped in the
629 		int isolated;
676 		isolated = __isolate_free_page(page, order);
677 		if (!isolated)
681 		nr_scanned += isolated - 1;
682 		total_isolated += isolated;
683 		cc->nr_freepages += isolated;
687 			blockpfn += isolated;
691 		blockpfn += isolated - 1;
692 		page += isolated - 1;
718 	 * pages requested were isolated. If there were any failures, 0 is
740  * Otherwise, function returns one-past-the-last PFN of isolated page
748 	unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
761 	for (; pfn < end_pfn; pfn += isolated,
768 		 * pfn could pass the block_end_pfn if isolated freepage
783 		isolated = isolate_freepages_block(cc, &isolate_start_pfn,
791 		if (!isolated)
820 	unsigned long active, inactive, isolated;
826 	isolated = node_page_state(pgdat, NR_ISOLATED_FILE) +
832 	 * compactors have already isolated to the limit, but are
840 	too_many = isolated > (inactive + active) / 2;
850  * @order:		to-be-isolated folio order
887  * The pages are isolated on cc->migratepages list (not required to be empty),
911 	 * Ensure that there are not too many pages isolated from the LRU
913 	 * delay for some time until fewer pages are isolated
943 			 * We have isolated all migration candidates in the
1042 				 * Hugepage was successfully isolated and placed
1053 			 * isolated. Fall-through as the check below handles
1256 		/* Successfully isolated */
1296 		 * We have isolated some pages, but then failed. Release them
1345 	 * there were no pages isolated in the block or if the block is
1676 		/* Skip fast search if enough freepages isolated */
1751 	 * successfully isolated from, zone-cached value, or the end of the
1770 	 * and free page scanners meet or enough free pages are isolated.
1814 		/* Are enough freepages isolated? */
1819 				 * freepages can be isolated next time.
1852  * from the isolated freelists in the block we are migrating to.
1902  * This is a migrate-callback that "frees" freepages back to the isolated
1927 	ISOLATE_NONE,		/* No pages isolated, continue scanning */
1928 	ISOLATE_SUCCESS,	/* Pages isolated, migrate */
2187 		 * Either we isolated something and proceed with migration. Or
2616 		 * happen if a page cannot be isolated (dirty/writeback in
2642 			 * We haven't isolated and migrated anything, but