On Tue, Jun 19, 2012 at 03:04:59PM +0200, Bartlomiej Zolnierkiewicz wrote: > > If the page is on the wrong free list, just isolate it or move it to the > > MIGRATE_ISOLATE free list at that point. If it has been allocated then > > migrate it and move the resulting free page to the MIGRATE_ISOLATE list. > > Thanks, this makes sense but still leaves us with some page allocation vs > alloc_contig_range() races (i.e. pages "in-flight" state being added/removed > to/from pcp lists so not being on the freelists and not being allocated). > The races should not be forever or open-ended. Once the pageblock is marked ISOLATE it should only take one pass to either move it from MIGRATE_CMA to MIGRATE_ISOLATE free lists or to migrate the page and free it to the MIGRATE_ISOLATE. I would be very surprised if this cannot be properly handled in alloc_contig_range() in a manner that does not wreck the page allocator fast paths. -- Mel Gorman SUSE Labs -- 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>