Re: [Xen-devel] [PATCH v4 1/3] libxc: do some retries in xc_cpupool_removecpu() for EBUSY case

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Juergen Gross writes ("[PATCH v4 1/3] libxc: do some retries in 
xc_cpupool_removecpu() for EBUSY case"):
> The hypervisor might return EBUSY when trying to remove a cpu from a
> cpupool when a domain running in this cpupool has pinned a vcpu
> temporarily. Do some retries in this case, perhaps the situation
> cleans up.

Unfortunately this patch is not acceptable because:

> +    for ( retries = 0; retries < NUM_RMCPU_BUSY_RETRIES; retries++ ) {
> +        err = do_sysctl_save(xch, &sysctl);
> +        if ( err < 0 && errno == EBUSY )
> +            sleep(1);

libxc may be called from within long-running daemons such as libvirt.

In such a system this sleep would enable an uncooperative or buggy
guest to block all toolstack operations for an extended period.

Sorry,
Ian.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel