| Message ID | 1438838837-28504-5-git-send-email-bharata@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Aug 06, 2015 at 10:57:10AM +0530, Bharata B Rao wrote: > This sync API will be used by the CPU hotplug code to wait for the CPU to > completely get removed before flagging the failure to the device_add > command. > > Sync version of this call is needed to correctly recover from CPU > realization failures when ->plug() handler fails. > > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > --- > cpus.c | 14 ++++++++++++++ > include/qom/cpu.h | 8 ++++++++ > 2 files changed, 22 insertions(+) > > diff --git a/cpus.c b/cpus.c > index 73ae2e7..9d9644e 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -999,6 +999,8 @@ 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); > + cpu->created = false; > + qemu_cond_signal(&qemu_cpu_cond); > qemu_mutex_unlock(&qemu_global_mutex); > return NULL; > } > @@ -1104,6 +1106,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > } > if (remove_cpu) { > qemu_tcg_destroy_vcpu(remove_cpu); > + cpu->created = false; > + qemu_cond_signal(&qemu_cpu_cond); > remove_cpu = NULL; > } > } > @@ -1283,6 +1287,16 @@ void cpu_remove(CPUState *cpu) > qemu_cpu_kick(cpu); > } > > +void cpu_remove_sync(CPUState *cpu) > +{ > + cpu->stop = true; > + cpu->exit = true; > + qemu_cpu_kick(cpu); It would be nicer for this to call the async cpu_remove() above, to ensure they stay in sync. > + while (cpu->created) { > + qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex); > + } > +} > + > /* For temporary buffers for forming a name */ > #define VCPU_THREAD_NAME_SIZE 16 > > diff --git a/include/qom/cpu.h b/include/qom/cpu.h > index 136d9fe..65c6852 100644 > --- a/include/qom/cpu.h > +++ b/include/qom/cpu.h > @@ -655,6 +655,14 @@ void cpu_resume(CPUState *cpu); > */ > void cpu_remove(CPUState *cpu); > > + /** > + * cpu_remove_sync: > + * @cpu: The CPU to remove. > + * > + * Requests the CPU to be removed and waits till it is removed. > + */ > +void cpu_remove_sync(CPUState *cpu); > + > /** > * qemu_init_vcpu: > * @cpu: The vCPU to initialize.
On Fri, Sep 04, 2015 at 04:11:38PM +1000, David Gibson wrote: > On Thu, Aug 06, 2015 at 10:57:10AM +0530, Bharata B Rao wrote: > > This sync API will be used by the CPU hotplug code to wait for the CPU to > > completely get removed before flagging the failure to the device_add > > command. > > > > Sync version of this call is needed to correctly recover from CPU > > realization failures when ->plug() handler fails. > > > > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > > --- > > cpus.c | 14 ++++++++++++++ > > include/qom/cpu.h | 8 ++++++++ > > 2 files changed, 22 insertions(+) > > > > diff --git a/cpus.c b/cpus.c > > index 73ae2e7..9d9644e 100644 > > --- a/cpus.c > > +++ b/cpus.c > > @@ -999,6 +999,8 @@ 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); > > + cpu->created = false; > > + qemu_cond_signal(&qemu_cpu_cond); > > qemu_mutex_unlock(&qemu_global_mutex); > > return NULL; > > } > > @@ -1104,6 +1106,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > > } > > if (remove_cpu) { > > qemu_tcg_destroy_vcpu(remove_cpu); > > + cpu->created = false; > > + qemu_cond_signal(&qemu_cpu_cond); > > remove_cpu = NULL; > > } > > } > > @@ -1283,6 +1287,16 @@ void cpu_remove(CPUState *cpu) > > qemu_cpu_kick(cpu); > > } > > > > +void cpu_remove_sync(CPUState *cpu) > > +{ > > + cpu->stop = true; > > + cpu->exit = true; > > + qemu_cpu_kick(cpu); > > It would be nicer for this to call the async cpu_remove() above, to > ensure they stay in sync. Makes sense, will incorporate this in the next iteration. Regards, Bharata.
diff --git a/cpus.c b/cpus.c index 73ae2e7..9d9644e 100644 --- a/cpus.c +++ b/cpus.c @@ -999,6 +999,8 @@ 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); + cpu->created = false; + qemu_cond_signal(&qemu_cpu_cond); qemu_mutex_unlock(&qemu_global_mutex); return NULL; } @@ -1104,6 +1106,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } if (remove_cpu) { qemu_tcg_destroy_vcpu(remove_cpu); + cpu->created = false; + qemu_cond_signal(&qemu_cpu_cond); remove_cpu = NULL; } } @@ -1283,6 +1287,16 @@ void cpu_remove(CPUState *cpu) qemu_cpu_kick(cpu); } +void cpu_remove_sync(CPUState *cpu) +{ + cpu->stop = true; + cpu->exit = true; + qemu_cpu_kick(cpu); + while (cpu->created) { + qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex); + } +} + /* For temporary buffers for forming a name */ #define VCPU_THREAD_NAME_SIZE 16 diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 136d9fe..65c6852 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -655,6 +655,14 @@ void cpu_resume(CPUState *cpu); */ void cpu_remove(CPUState *cpu); + /** + * cpu_remove_sync: + * @cpu: The CPU to remove. + * + * Requests the CPU to be removed and waits till it is removed. + */ +void cpu_remove_sync(CPUState *cpu); + /** * qemu_init_vcpu: * @cpu: The vCPU to initialize.
This sync API will be used by the CPU hotplug code to wait for the CPU to completely get removed before flagging the failure to the device_add command. Sync version of this call is needed to correctly recover from CPU realization failures when ->plug() handler fails. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> --- cpus.c | 14 ++++++++++++++ include/qom/cpu.h | 8 ++++++++ 2 files changed, 22 insertions(+)