Hi Michal, Thanks for your comments! As discussed, we will rework the patch set in another direction to hide memoryless node from normal slab users. Regards! Gerry On 2014/7/18 15:36, Michal Hocko wrote: > On Fri 11-07-14 15:37:26, Jiang Liu wrote: >> When CONFIG_HAVE_MEMORYLESS_NODES is enabled, cpu_to_node()/numa_node_id() >> may return a node without memory, and later cause system failure/panic >> when calling kmalloc_node() and friends with returned node id. >> So use cpu_to_mem()/numa_mem_id() instead to get the nearest node with >> memory for the/current cpu. >> >> If CONFIG_HAVE_MEMORYLESS_NODES is disabled, cpu_to_mem()/numa_mem_id() >> is the same as cpu_to_node()/numa_node_id(). > > The change makes difference only for really tiny memcgs. If we really > have all pages on unevictable list or anon with no swap allowed and that > is the reason why no node is set in scan_nodes mask then reclaiming > memoryless node or any arbitrary close one doesn't make any difference. > The current memcg might not have any memory on that node at all. > > So the change doesn't make any practical difference and the changelog is > misleading. > >> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> >> --- >> mm/memcontrol.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index a2c7bcb0e6eb..d6c4b7255ca9 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c >> @@ -1933,7 +1933,7 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) >> * we use curret node. >> */ >> if (unlikely(node == MAX_NUMNODES)) >> - node = numa_node_id(); >> + node = numa_mem_id(); >> >> memcg->last_scanned_node = node; >> return node; >> -- >> 1.7.10.4 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
