Re: [mm PATCH v5 4/7] mm: Initialize MAX_ORDER_NR_PAGES at a time instead of doing larger sections

} - first_init_pfn = max(zone->zone_start_pfn, first_init_pfn); + + /* If the zone is empty somebody else may have cleared out the zone */ + if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, + first_init_pfn)) { + pgdat_resize_unlock(pgdat, &flags); + pgdat_init_report_one_done(); + return 0;

+ } /* - * Initialize and free pages. We do it in two loops: first we initialize - * struct page, than free to buddy allocator, because while we are - * freeing pages we can access pages that are ahead (computing buddy - * page in __free_one_page()). + * Initialize and free pages in MAX_ORDER sized increments so + * that we can avoid introducing any issues with the buddy + * allocator. */ - for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) { - spfn = max_t(unsigned long, first_init_pfn, spfn); - nr_pages += deferred_init_pages(zone, spfn, epfn); - } - for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) { - spfn = max_t(unsigned long, first_init_pfn, spfn); - deferred_free_pages(spfn, epfn); - } + while (spfn < epfn) + nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn); + pgdat_resize_unlock(pgdat, &flags); /* Sanity check that the next zone really is unpopulated */ @@ -1602,9 +1689,9 @@ deferred_grow_zone(struct zone *zone, unsigned int order) {

unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);

- first_init_pfn = max(zone->zone_start_pfn, first_deferred_pfn); - - if (first_init_pfn >= pgdat_end_pfn(pgdat)) { + /* If the zone is empty somebody else may have cleared out the zone */ + if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, + first_deferred_pfn)) { pgdat_resize_unlock(pgdat, &flags); - return false; + return true;