Re: [libvirt] [PATCH v3] memtune: Let virsh know the unlimited value for memory tunables
On 01/12/2011 12:56 AM, Nikunj A. Dadhania wrote:
Here is the patch, now the set calls are also ull.
Still virCgroupGetMemoryUsage is not changed, this will require changes
in virDomainInfoPtr (info->memory). I am not sure if I should have them
in this patch.
It can be a separate patch, if desired, but it is probably still needed.
virDomainGetInfo is inherently limited - we can't change that API due to
backwards compatibility issues, so if we ever encounter a system with
more than 4T memory (1k * 4G limit of unsigned long), then the maxMem
and memory fields of virDomainInfoPtr have to be clamped at 4G on any
system with 32-bit long, rather than wrapping around. We probably also
ought to document this limitation, and point to getMemoryParameter as
the way to find a more accurate memory limits if virDomainGetInfo
returned clamped values.
From: Nikunj A. Dadhania <nikunj(a)linux.vnet.ibm.com>
Display unlimited when the memory cgroup settings says so. Unlimited is
represented by INT64_MAX in memory cgroup.
v3: Make virCgroupSet memory call ull
+++ b/src/util/cgroup.c
@@ -858,8 +858,11 @@ int virCgroupForDomain(virCgroupPtr driver ATTRIBUTE_UNUSED,
*
* Returns: 0 on success
*/
-int virCgroupSetMemory(virCgroupPtr group, unsigned long kb)
+int virCgroupSetMemory(virCgroupPtr group, unsigned long long kb)
{
+ if (kb > (VIR_DOMAIN_MEMORY_PARAM_UNLIMITED >> 10))
+ return -EINVAL;
+
return virCgroupSetValueU64(group,
VIR_CGROUP_CONTROLLER_MEMORY,
"memory.limit_in_bytes",
Not quite right. What if I want to change from a finite limit back to
unlimited? Then virCgroupSetMemory(group, UINT64_MAX) must recognize
that kb == VIR_DOMAIN_MEMORY_PARAM_UNLIMITED, and call
virCgroupSetValueU64(INT64_MAX) rathe than virCgroupSetValueU64(kb<<10).
@@ -883,6 +886,7 @@ int virCgroupGetMemoryUsage(virCgroupPtr group,
unsigned long *kb)
"memory.usage_in_bytes", &usage_in_bytes);
if (ret == 0)
*kb = (unsigned long) usage_in_bytes >> 10;
+
return ret;
Why the whitespace change?
@@ -927,8 +936,11 @@ int virCgroupGetMemoryHardLimit(virCgroupPtr
group, unsigned long *kb)
*
* Returns: 0 on success
*/
-int virCgroupSetMemorySoftLimit(virCgroupPtr group, unsigned long kb)
+int virCgroupSetMemorySoftLimit(virCgroupPtr group, unsigned long long kb)
{
+ if (kb > (VIR_DOMAIN_MEMORY_PARAM_UNLIMITED >> 10))
+ return -EINVAL;
+
Likewise on needing to allow the user to set the value back to unlimited.
+++ b/tools/virsh.c
@@ -2987,9 +2987,14 @@ cmdMemtune(vshControl * ctl, const vshCmd * cmd)
params[i].value.l);
break;
case VIR_DOMAIN_MEMORY_PARAM_ULLONG:
- vshPrint(ctl, "%-15s: %llu\n", params[i].field,
- params[i].value.ul);
+ {
+ if (params[i].value.ul == VIR_DOMAIN_MEMORY_PARAM_UNLIMITED)
+ vshPrint(ctl, "%-15s: unlimited\n", params[i].field);
+ else
+ vshPrint(ctl, "%-15s: %llu\n", params[i].field,
+ params[i].value.ul);
Do we want any back-compat considerations? That is, if a newer virsh is
talking to an older server, which still answered INT64_MAX>>10 instead
of the new VIR_DOMAIN_MEMORY_PARAM_UNLIMITED, should we recognize that
situation as another reason to print "unlimited"?
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
Attachments:
- signature.asc (application/pgp-signature — 619 bytes)