On 10/03/2011 04:36 PM, Kirill A. Shutemov wrote:
On Mon, Oct 03, 2011 at 04:26:41PM +0400, Glauber Costa wrote:
On 10/03/2011 04:25 PM, Kirill A. Shutemov wrote:
On Mon, Oct 03, 2011 at 04:19:18PM +0400, Glauber Costa wrote:
On 10/03/2011 04:14 PM, Kirill A. Shutemov wrote:
On Mon, Oct 03, 2011 at 02:18:42PM +0400, Glauber Costa wrote:
This patch introduces kmem.tcp_current_memory file, living in the
kmem_cgroup filesystem. It is a simple read-only file that displays the
amount of kernel memory currently consumed by the cgroup.
Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
CC: David S. Miller<davem@xxxxxxxxxxxxx>
CC: Hiroyouki Kamezawa<kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Eric W. Biederman<ebiederm@xxxxxxxxxxxx>
---
Documentation/cgroups/memory.txt | 1 +
mm/memcontrol.c | 11 +++++++++++
2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 1ffde3e..f5a539d 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -79,6 +79,7 @@ Brief summary of control files.
memory.independent_kmem_limit # select whether or not kernel memory limits are
independent of user limits
memory.kmem.tcp.max_memory # set/show hard limit for tcp buf memory
+ memory.kmem.tcp.current_memory # show current tcp buf memory allocation
Both are in pages, right?
Shouldn't it be scaled to bytes and named uniform with other memcg file?
memory.kmem.tcp.limit_in_bytes/usage_in_bytes.
You are absolutely correct.
Since the internal tcp comparison works, I just ended up never noticing
this.
Should we have failcnt and max_usage_in_bytes for tcp as well?
Well, we get a fail count from the tracer anyway, so I don't really see
a need for that. I see value in having it for the slab allocation
itself, but since this only controls the memory pressure framework, I
think we can live without it.
That said, this is not a strong opinion. I can add it if you'd prefer.
It's good for userspace to have the same set of files for all domains:
- memory;
- memory.memsw;
- memory.kmem;
- memory.kmem.tcp;
- etc.
Userspace can reuse code for handling them in this case.
Ok. Back on this.
Not all domains have all files anyway.
max_usage seems to be a property of the main memcg, not of its domains.
failcnt is present on memsw, and on that only. The problem here, is that
this can fail ( and usually will ) in codepaths outside the memory
controller. (see net/core/sock.c:__sk_mem_schedule)
Also, max_usage makes sense for kernel memory as a whole, but I don't
think it makes sense here as we're only controlling a specific pressure
condition.
So in a nutshell: I'd like to leave this alone, and add
kmem.max_usage_in_bytes and kmem.failcnt to the to soon-to-land-here
slab accounting patches. (Where the actual allocation happens)
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