On Wed, Jun 23, 2010 at 6:50 AM, Eric Blake <eblake@xxxxxxxxxx> wrote:
> On 05/23/2010 07:15 AM, Ryota Ozaki wrote:
>
> [Apologies for the delayed review, and for the fact that you had to ping
> us to remind us this had not been visited]
Nevermind. I'm also sometimes late ;-)
>
>> Through conversation with Kumar L Srikanth-B22348, I found
>> that the function of getting memory usage (e.g., virsh dominfo)
>> doesn't work for lxc with ns subsystem of cgroup enabled.
>>
>> This is because of features of ns and memory subsystems.
>> Ns creates child cgroup on every process fork and as a result
>> processes in a container are not assigned in a cgroup for
>> domain (e.g., libvirt/lxc/test1/). For example, libvirt_lxc
>> and init (or somewhat specified in XML) are assigned into
>> libvirt/lxc/test1/8839/ and libvirt/lxc/test1/8839/8849/,
>> respectively. On the other hand, memory subsystem accounts
>> memory usage within a group of processes by default, i.e.,
>> it does not take any child (and descendent) groups into
>> account. With the two features, virsh dominfo which just
>> checks memory usage of a cgroup for domain always returns
>> zero because the cgroup has no process.
>>
>> Setting memory.use_hierarchy of a group allows to account
>> (and limit) memory usage of every descendent groups of the group.
>
> s/descendent/descendant/
ouch.
>
>> By setting it of a cgroup for domain, we can get proper memory
>> usage of lxc with ns subsystem enabled. (To be exact, the
>> setting is required only when memory and ns subsystems are
>> enabled at the same time, e.g., mount -t cgroup none /cgroup.)
>> ---
>> src/util/cgroup.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++---
>> 1 files changed, 59 insertions(+), 4 deletions(-)
>>
>> diff --git a/src/util/cgroup.c b/src/util/cgroup.c
>> index b8b2eb5..f7d6b41 100644
>> --- a/src/util/cgroup.c
>> +++ b/src/util/cgroup.c
>> @@ -443,7 +443,38 @@ static int virCgroupCpuSetInherit(virCgroupPtr parent, virCgroupPtr group)
>> return rc;
>> }
>>
>> -static int virCgroupMakeGroup(virCgroupPtr parent, virCgroupPtr group, int create)
>> +static int virCgroupSetMemoryUseHierarchy(virCgroupPtr group)
>> +{
>> + int rc = 0;
>> + unsigned long long value;
>> + const char *filename = "memory.use_hierarchy";
>> +
>> + rc = virCgroupGetValueU64(group,
>> + VIR_CGROUP_CONTROLLER_MEMORY,
>> + filename, &value);
>> + if (rc != 0) {
>> + VIR_ERROR("Failed to read %s/%s (%d)", group->path, filename, rc);
>
> Needs _() translation these days; 'make syntax-check' should have caught
> this.
Oh, sorry. I'll fix all you mention in this patch as well as missing ones in
the previous patch.
>
>> + return rc;
>> + }
>> +
>> + /* Setting twice causes error, so if already enabled, skip setting */
>> + if (value == 1)
>> + return 0;
>> +
>> + VIR_DEBUG("Setting up %s/%s", group->path, filename);
>
> Debug remains untranslated...
>
>> + rc = virCgroupSetValueU64(group,
>> + VIR_CGROUP_CONTROLLER_MEMORY,
>> + filename, 1);
>> +
>> + if (rc != 0) {
>> + VIR_ERROR("Failed to set %s/%s (%d)", group->path, filename, rc);
>
> ...but another VIR_ERROR that needs translation.
>
>> + }
>> +
>> + return rc;
>> +}
>> +
>> +static int virCgroupMakeGroup(virCgroupPtr parent, virCgroupPtr group,
>> + int create, int memory_hierarchy)
>
> Based on how this is being used, it seems like you should use
> bool/true/false rather than int/0/1 for memory_hierarchy.
Indeed. Will fix.
>
>> {
>> int i;
>> int rc = 0;
>> @@ -477,6 +508,20 @@ static int virCgroupMakeGroup(virCgroupPtr parent, virCgroupPtr group, int creat
>> break;
>> }
>> }
>> + /*
>> + * Note that virCgroupSetMemoryUseHierarchy should always be
>> + * called prior to creating subcgroups and attaching tasks.
>> + */
>> + if (memory_hierarchy &&
>> + group->controllers[VIR_CGROUP_CONTROLLER_MEMORY].mountPoint != NULL &&
>> + (i == VIR_CGROUP_CONTROLLER_MEMORY ||
>> + STREQ(group->controllers[i].mountPoint, group->controllers[VIR_CGROUP_CONTROLLER_MEMORY].mountPoint))) {
>> + rc = virCgroupSetMemoryUseHierarchy(group);
>> + if (rc != 0) {
>> + VIR_FREE(path);
>> + break;
>> + }
>> + }
>> }
>>
>> VIR_FREE(path);
>> @@ -553,7 +598,7 @@ static int virCgroupAppRoot(int privileged,
>> if (rc != 0)
>> goto cleanup;
>>
>> - rc = virCgroupMakeGroup(rootgrp, *group, create);
>> + rc = virCgroupMakeGroup(rootgrp, *group, create, 0);
>>
>
> ACK with those nits addressed. Hopefully a v2 submission won't take as
> much time on the review side of things.
Thanks.
ozaki-r
>
> --
> Eric Blake eblake@xxxxxxxxxx +1-801-349-2682
> Libvirt virtualization library http://libvirt.org
>
>
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list