On Fri 14-01-22 00:29:37, Wei Yang wrote: > On Wed, Jan 12, 2022 at 09:56:15AM +0100, Michal Hocko wrote: > >On Wed 12-01-22 00:46:34, Wei Yang wrote: > >> On Tue, Jan 11, 2022 at 09:40:20AM +0100, Michal Hocko wrote: > >> >On Tue 11-01-22 01:02:59, Wei Yang wrote: > >> >> Instead of use "-1", let's use NUMA_NO_NODE for consistency. > >> >> > >> >> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> > >> > > >> >I am not really sure this is worth it. After the merge window I plan to > >> >post http://lkml.kernel.org/r/20211214100732.26335-1-mhocko@xxxxxxxxxx. > >> > >> Give me some time to understand it :-) > > > >Just for the record, here is what I have put on top of that series: > > Ok, I got what you try to resolve. I am ok with the following change except > one point. > > >--- > >>From b7195eba02fe6308a6927450f4630057c05e808e Mon Sep 17 00:00:00 2001 > >From: Wei Yang <richard.weiyang@xxxxxxxxx> > >Date: Tue, 11 Jan 2022 09:45:25 +0100 > >Subject: [PATCH] memcg: do not tweak node in alloc_mem_cgroup_per_node_info > > > >alloc_mem_cgroup_per_node_info is allocated for each possible node and > >this used to be a problem because not !node_online nodes didn't have > >appropriate data structure allocated. This has changed by "mm: handle > >uninitialized numa nodes gracefully" so we can drop the special casing > >here. > > > >Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> > >Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > >--- > > mm/memcontrol.c | 14 ++------------ > > 1 file changed, 2 insertions(+), 12 deletions(-) > > > >diff --git a/mm/memcontrol.c b/mm/memcontrol.c > >index 781605e92015..ed19a21ee14e 100644 > >--- a/mm/memcontrol.c > >+++ b/mm/memcontrol.c > >@@ -5044,18 +5044,8 @@ struct mem_cgroup *mem_cgroup_from_id(unsigned short id) > > static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) > > { > > struct mem_cgroup_per_node *pn; > >- int tmp = node; > >- /* > >- * This routine is called against possible nodes. > >- * But it's BUG to call kmalloc() against offline node. > >- * > >- * TODO: this routine can waste much memory for nodes which will > >- * never be onlined. It's better to use memory hotplug callback > >- * function. > >- */ > > Do you think this TODO is not related to this change? It is not really related but I am not sure how useful it is. Essentially any allocation that is per-possible node is in the same situation and if we really need to deal with large and sparse possible nodes masks. If you want me to keep the TODO I will do it though. -- Michal Hocko SUSE Labs
