[libvirt] [PATCH] openvz: read vmguarpages/privvmpages to set memory tunables [v2]
Eric Blake
eblake at redhat.com
Wed May 2 19:49:06 UTC 2012
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 at redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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