On 2015/6/26 19:04, Mel Gorman wrote: > On Fri, Jun 26, 2015 at 06:09:05PM +0800, Xishi Qiu wrote: >> memmap_init_zone() >> ... >> if ((z->zone_start_pfn <= pfn) >> && (pfn < zone_end_pfn(z)) >> && !(pfn & (pageblock_nr_pages - 1))) >> set_pageblock_migratetype(page, MIGRATE_MOVABLE); >> ... >> >> If the pfn does not align to pageblock, it will not init the migratetype. > > What important impact does that have? It should leave a partial pageblock > as MIGRATE_UNMOVABLE which is fine by me. > Hi Mel, The impact is less, it's OK to ignore it. Thanks, Xishi Qiu >> So call it for every page, it will takes more time, but it doesn't matter, >> this function will be called only in boot or hotadd memory. >> > > It's a lot of additional overhead to add to memory initialisation. It > would need to be for an excellent reason with no alternative solution. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>