Hi, what do you think about the patch below? >From b983695b92b5be58f31c719fada1d3245f7b6768 Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko@xxxxxxx> Date: Fri, 20 Aug 2010 15:39:16 +0200 Subject: [PATCH] Make is_mem_section_removable more conformable with offlining code Currently is_mem_section_removable checks whether each pageblock from the given pfn range is of MIGRATE_MOVABLE type or if it is free. If both are false then the range is considered non removable. On the other hand, offlining code (more specifically set_migratetype_isolate) doesn't care whether a page is free and instead it just checks the migrate type of the page and whether the page's zone is movable. This can lead into a situation when a node is marked as removable even though all pages are neither MIGRATE_MOVABLE nor the zone is ZONE_MOVABLE. Also we can mark a node as not removable just because a pageblock is MIGRATE_RESERVE and not free (and this situation is much more probable). --- mm/memory_hotplug.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a4cfcdc..da20568 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -611,10 +611,10 @@ int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) type = get_pageblock_migratetype(page); /* - * A pageblock containing MOVABLE or free pages is considered - * removable + * A pageblock containing MOVABLE or page from movable + * zone are considered removable */ - if (type != MIGRATE_MOVABLE && !pageblock_free(page)) + if (type != MIGRATE_MOVABLE && zone_idx(page) != ZONE_MOVABLE) return 0; /* -- 1.7.1 -- Michal Hocko L3 team SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>