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] > 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/ > 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. > + 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. > { > 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. -- Eric Blake eblake@xxxxxxxxxx +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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