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From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>,
	mdroth@linux.vnet.ibm.com, agraf@suse.de, qemu-devel@nongnu.org,
	Chen Fan <chen.fan.fnst@cn.fujitsu.com>,
	pbonzini@redhat.com, qemu-ppc@nongnu.org,
	tyreld@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com,
	Gu Zheng <guz.fnst@cn.fujitsu.com>,
	imammedo@redhat.com, afaerber@suse.de,
	david@gibson.dropbear.id.au
Subject: Re: [Qemu-devel] [PATCH v5 04/10] cpu: Reclaim vCPU objects
Date: Wed, 2 Dec 2015 09:20:38 +0530	[thread overview]
Message-ID: <20151202035037.GD16342@in.ibm.com> (raw)
In-Reply-To: <565BFB2C.6040201@ozlabs.ru>

On Mon, Nov 30, 2015 at 06:30:52PM +1100, Alexey Kardashevskiy wrote:
> On 11/20/2015 11:54 PM, Bharata B Rao wrote:
> >From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> >
> >In order to deal well with the kvm vcpus (which can not be removed without any
> >protection), we do not close KVM vcpu fd, just record and mark it as stopped
> >into a list, so that we can reuse it for the appending cpu hot-add request if
> >possible. It is also the approach that kvm guys suggested:
> >https://www.mail-archive.com/kvm@vger.kernel.org/msg102839.html
> >
> >Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> >Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> >Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
> >Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> >                [- Explicit CPU_REMOVE() from qemu_kvm/tcg_destroy_vcpu()
> >                   isn't needed as it is done from cpu_exec_exit()]
> >Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> >---
> >  cpus.c               | 41 +++++++++++++++++++++++++++++++++++++
> >  include/qom/cpu.h    | 10 +++++++++
> >  include/sysemu/kvm.h |  1 +
> >  kvm-all.c            | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-
> >  kvm-stub.c           |  5 +++++
> >  5 files changed, 113 insertions(+), 1 deletion(-)
> >
> >diff --git a/cpus.c b/cpus.c
> >index 877bd70..af2b274 100644
> >--- a/cpus.c
> >+++ b/cpus.c
> >@@ -953,6 +953,21 @@ void async_run_on_cpu(CPUState *cpu, void (*func)(void *data), void *data)
> >      qemu_cpu_kick(cpu);
> >  }
> >
> >+static void qemu_kvm_destroy_vcpu(CPUState *cpu)
> >+{
> >+    if (kvm_destroy_vcpu(cpu) < 0) {
> >+        error_report("kvm_destroy_vcpu failed.\n");
> >+        exit(EXIT_FAILURE);
> >+    }
> >+
> >+    object_unparent(OBJECT(cpu));
> >+}
> >+
> >+static void qemu_tcg_destroy_vcpu(CPUState *cpu)
> >+{
> >+    object_unparent(OBJECT(cpu));
> >+}
> >+
> >  static void flush_queued_work(CPUState *cpu)
> >  {
> >      struct qemu_work_item *wi;
> >@@ -1053,6 +1068,11 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
> >              }
> >          }
> >          qemu_kvm_wait_io_event(cpu);
> >+        if (cpu->exit && !cpu_can_run(cpu)) {
> >+            qemu_kvm_destroy_vcpu(cpu);
> >+            qemu_mutex_unlock(&qemu_global_mutex);
> 
> 
> Nit: qemu_mutex_unlock_iothread() may be? Or it is important for
> iothread_locked to remain "true"? It does not seem to be used much though.

This patch is quite old and qemu_global_mutex got changed to
qemu_mutex_unlock_iothread() some time ago in this part of the code.

Thanks for noticing this, will fix this in next version.

Regards,
Bharata.

  reply	other threads:[~2015-12-02  3:51 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20 12:54 [Qemu-devel] [PATCH v5 00/10] sPAPR CPU hotplug Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 01/10] vl: Don't allow CPU toplogies with partially filled cores Bharata B Rao
2015-12-01  0:37   ` David Gibson
2015-12-02  3:04     ` Bharata B Rao
2015-12-02 13:52   ` Igor Mammedov
2015-12-02 14:14     ` Eduardo Habkost
2015-12-02 14:38       ` Bharata B Rao
2015-12-02 15:19         ` Eduardo Habkost
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 02/10] exec: Remove cpu from cpus list during cpu_exec_exit() Bharata B Rao
2015-12-01  0:44   ` David Gibson
2015-12-02  3:47     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 03/10] exec: Do vmstate unregistration from cpu_exec_exit() Bharata B Rao
2015-12-01  0:46   ` David Gibson
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 04/10] cpu: Reclaim vCPU objects Bharata B Rao
2015-11-30  7:30   ` Alexey Kardashevskiy
2015-12-02  3:50     ` Bharata B Rao [this message]
2015-12-01  0:55   ` David Gibson
2015-12-02  5:28     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 05/10] cpu: Add a sync version of cpu_remove() Bharata B Rao
2015-12-01  0:57   ` David Gibson
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 06/10] xics_kvm: Add cpu_destroy method to XICS Bharata B Rao
2015-12-01  1:01   ` David Gibson
2015-12-02  5:45     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 07/10] spapr: Enable CPU hotplug for pseries-2.5 and add CPU DRC DT entries Bharata B Rao
2015-12-01  1:06   ` David Gibson
2015-12-02  5:47     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 08/10] spapr: CPU hotplug support Bharata B Rao
2015-12-01  1:30   ` David Gibson
2015-12-01  4:48     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 09/10] spapr: CPU hot unplug support Bharata B Rao
2015-12-01  1:34   ` David Gibson
2015-12-02  5:49     ` Bharata B Rao
2015-11-20 12:54 ` [Qemu-devel] [PATCH v5 10/10] target-ppc: Enable CPU hotplug for POWER8 CPU family Bharata B Rao
2015-11-23 11:54 ` [Qemu-devel] [PATCH v5 00/10] sPAPR CPU hotplug Peter Krempa
2015-11-23 13:04   ` Christian Borntraeger
2015-12-01  1:43     ` David Gibson

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