From: Ian Jackson <Ian.Jackson@eu.citrix.com>
To: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
xen-devel@lists.xen.org
Subject: Re: [PATCH v4 1/3] libxc: do some retries in xc_cpupool_removecpu() for EBUSY case
Date: Thu, 14 Apr 2016 17:04:57 +0100 [thread overview]
Message-ID: <22287.49065.99116.353107@mariner.uk.xensource.com> (raw)
In-Reply-To: <1457587634-22819-2-git-send-email-jgross@suse.com>
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.
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next prev parent reply other threads:[~2016-04-14 16:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 5:27 [PATCH v4 0/3] add hypercall option to temporarily pin a vcpu Juergen Gross
2016-03-10 5:27 ` [PATCH v4 1/3] libxc: do some retries in xc_cpupool_removecpu() for EBUSY case Juergen Gross
2016-03-10 10:26 ` Dario Faggioli
2016-03-10 17:16 ` Wei Liu
2016-04-12 13:02 ` Olaf Hering
2016-04-12 13:45 ` Juergen Gross
2016-04-12 13:50 ` Olaf Hering
2016-04-12 13:57 ` Wei Liu
2016-04-14 16:04 ` Ian Jackson [this message]
2016-03-10 5:27 ` [PATCH v4 2/3] libxl: print message how to recover from xl cpupool-cpu-remove errors Juergen Gross
2016-04-14 16:06 ` Ian Jackson
2016-04-14 17:10 ` Dario Faggioli
2016-04-14 17:22 ` Ian Jackson
2016-04-14 17:27 ` Dario Faggioli
2016-03-10 5:27 ` [PATCH v4 3/3] libxl: add force option for xl vcpu-pin Juergen Gross
2016-03-10 10:25 ` Dario Faggioli
2016-03-10 17:17 ` Wei Liu
2016-04-14 16:10 ` Ian Jackson
2016-04-14 17:18 ` Dario Faggioli
2016-03-22 7:36 ` [PATCH v4 0/3] add hypercall option to temporarily pin a vcpu Juergen Gross
2016-03-24 14:03 ` Wei Liu
2016-03-24 17:58 ` Juergen Gross
2016-03-24 19:41 ` Wei Liu
2016-03-30 10:28 ` Juergen Gross
2016-03-30 14:23 ` Konrad Rzeszutek Wilk
2016-04-14 16:11 ` Ian Jackson
2016-04-14 19:15 ` Konrad Rzeszutek Wilk
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