On Fri 02-04-21 18:38:54, Neil Sun wrote: > This patch makes shrink_slab() with task's memcg in drop_slab_node(), > so we can free reclaimable slab objects belongs to memcg /lxc/i-vbe1u8o7 > with following command:
You are changing semantic of the existing user interface. This knob has never been memcg aware and it is supposed to have a global impact. I do not think we can simply change that without some users being surprised or even breaking them. > cgexec -g memory:/lxc/i-vbe1u8o7 sysctl vm.drop_caches=2 > > Test with following steps: > > root@i-yl0pwrt8:~# free -h > total used free shared buff/cache > available > Mem: 62Gi 265Mi 62Gi 1.0Mi 290Mi > 61Gi > Swap: 31Gi 0B 31Gi > root@i-yl0pwrt8:~# (cd /tmp && /root/generate_slab_cache) > root@i-yl0pwrt8:~# free -h > total used free shared buff/cache > available > Mem: 62Gi 266Mi 60Gi 1.0Mi 2.2Gi > 61Gi > Swap: 31Gi 0B 31Gi > root@i-yl0pwrt8:~# cgcreate -g memory:/lxc/i-vbe1u8o7 > root@i-yl0pwrt8:~# cgexec -g memory:/lxc/i-vbe1u8o7 /root/generate_slab_cache > root@i-yl0pwrt8:~# free -h > total used free shared buff/cache > available > Mem: 62Gi 267Mi 58Gi 1.0Mi 4.1Gi > 61Gi > Swap: 31Gi 0B 31Gi > root@i-yl0pwrt8:~# cgexec -g memory:/lxc/i-vbe1u8o7 sysctl vm.drop_caches=2 > vm.drop_caches = 2 > root@i-yl0pwrt8:~# free -h > total used free shared buff/cache > available > Mem: 62Gi 268Mi 60Gi 1.0Mi 2.2Gi > 61Gi > Swap: 31Gi 0B 31Gi > root@i-yl0pwrt8:~# sysctl vm.drop_caches=2 > vm.drop_caches = 2 > root@i-yl0pwrt8:~# free -h > total used free shared buff/cache > available > Mem: 62Gi 267Mi 62Gi 1.0Mi 290Mi > 61Gi > Swap: 31Gi 0B 31Gi > > Signed-off-by: Neil Sun <[email protected]> > --- > mm/vmscan.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 562e87cb..81d770a 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -702,7 +702,7 @@ void drop_slab_node(int nid) > return; > > freed = 0; > - memcg = mem_cgroup_iter(NULL, NULL, NULL); > + memcg = mem_cgroup_from_task(current); > do { > freed += shrink_slab(GFP_KERNEL, nid, memcg, 0); > } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL); > -- > 2.7.4 -- Michal Hocko SUSE Labs
