Re: [libvirt] [PATCH] openvz: read vmguarpages/privvmpages to set memory tunables [v2]
On 04/26/2012 05:16 AM, Guido Günther wrote:
---
This is a reworked version of the patch already sent, now adding
handling for "unlimited" (represented by LONG_MAX in openvz) as well as
a schema testcase. I also switched all value to unsigned long long to
avoid overflows.
Note that privvmpages is the amount of memory available to the
application. The total memory usage of the container might be higher due
to used kernel memory. This does probably warrant an extra tunable
later. O.k. to apply?
Cheers,
-- Guido
+static int
+openvzReadMemConf(virDomainDefPtr def, int veid)
+{
+ int ret;
+ char *temp = NULL;
+ unsigned long long barrier, limit;
+ const char *param;
+ unsigned long kb_per_pages;
+
+ kb_per_pages = sysconf(_SC_PAGESIZE) / 1024;
In general, you should be prepared for sysconf() to fail...
+ if (kb_per_pages == -1) {
but you already divided by 1024, so failure will no longer show as -1 at
this point.
+
+ if (sscanf(output, "%llu %llu", barrier, limit) != 2) {
sscanf() can't detect overflow. I'd rather use virStrToLong_ull() for
safety.
> +
> +static int
> +openvzDomainGetMemoryParameters(virDomainPtr domain,
> + virTypedParameterPtr params,
> + int *nparams,
> + unsigned int flags)
> +{
> + int i, result = -1;
> + const char *name;
> + long kb_per_pages;
> + unsigned long long barrier, limit, val;
> +
> + virCheckFlags(0, -1);
> +
> + kb_per_pages = sysconf(_SC_PAGESIZE) / 1024;
+ if (kb_per_pages == -1) {
Oops, another inability to detect failure.
> +
> +static int
> +openvzDomainSetMemoryParameters(virDomainPtr domain,
> + virTypedParameterPtr params,
> + int nparams,
> + unsigned int flags)
> +{
> + int i, result = -1;
> + long kb_per_pages;
> +
> + kb_per_pages = sysconf(_SC_PAGESIZE) / 1024;
+ if (kb_per_pages == -1) {
And again.
But the bulk of this patch looks reasonable. Would you mind respinning
a v2 to address the nits, and we can probably get this in 0.9.12 even if
it misses rc1.
--
Eric Blake eblake(a)redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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