>> number of isolate page block is almost always 0. then if we have such counter, >> we almost always can avoid zone->lock. Just idea. > > Yeb. I thought about it but unfortunately we can't have a counter for MIGRATE_ISOLATE. > Because we have to tweak in page free path for pages which are going to free later after we > mark pageblock type to MIGRATE_ISOLATE. I mean, if (nr_isolate_pageblock != 0) free_pages -= nr_isolated_free_pages(); // your counting logic return __zone_watermark_ok(z, alloc_order, mark, classzone_idx, alloc_flags, free_pages); I don't think this logic affect your race. zone_watermark_ok() is already racy. then new little race is no big matter. -- 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>