From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx135.postini.com [74.125.245.135]) by kanga.kvack.org (Postfix) with SMTP id 38FD06B005C for ; Wed, 27 Jun 2012 11:48:32 -0400 (EDT) Date: Wed, 27 Jun 2012 17:48:27 +0200 From: Michal Hocko Subject: Re: memcg: cat: memory.memsw.* : Operation not supported Message-ID: <20120627154827.GA4420@tiehlicka.suse.cz> References: <2a1a74bf-fbb5-4a6e-b958-44fff8debff2@zmail13.collab.prod.int.phx2.redhat.com> <34bb8049-8007-496c-8ffb-11118c587124@zmail13.collab.prod.int.phx2.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <34bb8049-8007-496c-8ffb-11118c587124@zmail13.collab.prod.int.phx2.redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Zhouping Liu Cc: linux-mm@kvack.org, Li Zefan , Tejun Heo , CAI Qian , LKML On Tue 26-06-12 23:49:15, Zhouping Liu wrote: > hi, all > > when I used memory cgroup in latest mainline, the following error occurred: > > # mount -t cgroup -o memory xxx /cgroup/ > # ll /cgroup/memory.memsw.* > -rw-r--r--. 1 root root 0 Jun 26 23:17 /cgroup/memory.memsw.failcnt > -rw-r--r--. 1 root root 0 Jun 26 23:17 /cgroup/memory.memsw.limit_in_bytes > -rw-r--r--. 1 root root 0 Jun 26 23:17 /cgroup/memory.memsw.max_usage_in_bytes > -r--r--r--. 1 root root 0 Jun 26 23:17 /cgroup/memory.memsw.usage_in_bytes > # cat /cgroup/memory.memsw.* > cat: /cgroup/memory.memsw.failcnt: Operation not supported > cat: /cgroup/memory.memsw.limit_in_bytes: Operation not supported > cat: /cgroup/memory.memsw.max_usage_in_bytes: Operation not supported > cat: /cgroup/memory.memsw.usage_in_bytes: Operation not supported > > I'm confusing why it can't read memory.memsw.* files. Those files are exported if CONFIG_CGROUP_MEM_RES_CTLR_SWAP=y even if the feature is turned off when any attempt to open the file returns EOPNOTSUPP which is exactly what you are seeing. This is a deliberate decision see: b6d9270d (memcg: always create memsw files if CONFIG_CGROUP_MEM_RES_CTLR_SWAP). Does this help to explain your problem? Do you actually see any problem with this behavior? Thanks -- Michal Hocko SUSE Labs 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@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org