[libvirt] [PATCH] qemuSetupMemoryCgroup: Handle hard_limit properly

[Michal Privoznik]

On 20.08.2013 14:11, Ján Tomko wrote:
> On 08/20/2013 11:10 AM, Michal Privoznik wrote:
>> Since 16bcb3 we have a regression. The hard_limit is set
>> unconditionally. By default, the limit is zero. Hence, if user hasn't
>> configured any, we set the zero in cgroup subsystem making the kernel
>> kill the corresponding qemu process immediately. The proper fix is to
>> set hard_limit iff user has configure any.
>> ---
>>  src/qemu/qemu_cgroup.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
>> index 9673e8e..e27945e 100644
>> --- a/src/qemu/qemu_cgroup.c
>> +++ b/src/qemu/qemu_cgroup.c
>> @@ -428,7 +428,8 @@ qemuSetupMemoryCgroup(virDomainObjPtr vm)
>>          }
>>      }
>>  
>> -    if (virCgroupSetMemoryHardLimit(priv->cgroup, vm->def->mem.hard_limit) < 0)
>> +    if (vm->def->mem.hard_limit != 0 &&
>> +        virCgroupSetMemoryHardLimit(priv->cgroup, vm->def->mem.hard_limit) < 0)
>>          return -1;
>>  
>>      if (vm->def->mem.soft_limit != 0 &&
>>
> 
> This still calls SetMaxMemLock with 0 if mem.hard_limit is 0. According to
> commit 9395894 [1], it seems this won't be enough for VFIO passthrough
> (although I haven't tested it). (Commit 6d8ebc7 [2] changed this to use
> qemuDomainMemoryLimit)
> 
> Jan
> 
> [1] http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=9395894
> [2] http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=6d8ebc7

I've posted a separate patch for that. So if you agree, can I push this one?

Michal