diff mbox

[v2,3/3] libxc: do some retries in xc_cpupool_removecpu() for EBUSY case

Message ID 1456822933-25041-4-git-send-email-jgross@suse.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jürgen Groß March 1, 2016, 9:02 a.m. UTC
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.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 tools/libxc/xc_cpupool.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Comments

Wei Liu March 1, 2016, 11:58 a.m. UTC | #1
On Tue, Mar 01, 2016 at 10:02:13AM +0100, Juergen Gross wrote:
> 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.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
>  tools/libxc/xc_cpupool.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libxc/xc_cpupool.c b/tools/libxc/xc_cpupool.c
> index c42273e..9f2f95c 100644
> --- a/tools/libxc/xc_cpupool.c
> +++ b/tools/libxc/xc_cpupool.c
> @@ -20,8 +20,11 @@
>   */
>  
>  #include <stdarg.h>
> +#include <unistd.h>
>  #include "xc_private.h"
>  
> +#define LIBXC_BUSY_RETRIES 5
> +
>  static int do_sysctl_save(xc_interface *xch, struct xen_sysctl *sysctl)
>  {
>      int ret;
> @@ -141,13 +144,21 @@ int xc_cpupool_removecpu(xc_interface *xch,
>                           uint32_t poolid,
>                           int cpu)
>  {
> +    unsigned retries;
> +    int err;
>      DECLARE_SYSCTL;
>  
>      sysctl.cmd = XEN_SYSCTL_cpupool_op;
>      sysctl.u.cpupool_op.op = XEN_SYSCTL_CPUPOOL_OP_RMCPU;
>      sysctl.u.cpupool_op.cpupool_id = poolid;
>      sysctl.u.cpupool_op.cpu = (cpu < 0) ? XEN_SYSCTL_CPUPOOL_PAR_ANY : cpu;
> -    return do_sysctl_save(xch, &sysctl);
> +    for (retries = 0; retries < LIBXC_BUSY_RETRIES; retries++) {

Libxc coding style requires spaces between ().

> +        err = do_sysctl_save(xch, &sysctl);
> +        if (err >= 0 || errno != EBUSY)

Ditto.

> +            break;
> +        sleep(1);
> +    }
> +    return err;
>  }
>  
>  int xc_cpupool_movedomain(xc_interface *xch,
> -- 
> 2.6.2
>
Jürgen Groß March 1, 2016, 11:59 a.m. UTC | #2
On 01/03/16 12:58, Wei Liu wrote:
> On Tue, Mar 01, 2016 at 10:02:13AM +0100, Juergen Gross wrote:
>> 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.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>>  tools/libxc/xc_cpupool.c | 13 ++++++++++++-
>>  1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/libxc/xc_cpupool.c b/tools/libxc/xc_cpupool.c
>> index c42273e..9f2f95c 100644
>> --- a/tools/libxc/xc_cpupool.c
>> +++ b/tools/libxc/xc_cpupool.c
>> @@ -20,8 +20,11 @@
>>   */
>>  
>>  #include <stdarg.h>
>> +#include <unistd.h>
>>  #include "xc_private.h"
>>  
>> +#define LIBXC_BUSY_RETRIES 5
>> +
>>  static int do_sysctl_save(xc_interface *xch, struct xen_sysctl *sysctl)
>>  {
>>      int ret;
>> @@ -141,13 +144,21 @@ int xc_cpupool_removecpu(xc_interface *xch,
>>                           uint32_t poolid,
>>                           int cpu)
>>  {
>> +    unsigned retries;
>> +    int err;
>>      DECLARE_SYSCTL;
>>  
>>      sysctl.cmd = XEN_SYSCTL_cpupool_op;
>>      sysctl.u.cpupool_op.op = XEN_SYSCTL_CPUPOOL_OP_RMCPU;
>>      sysctl.u.cpupool_op.cpupool_id = poolid;
>>      sysctl.u.cpupool_op.cpu = (cpu < 0) ? XEN_SYSCTL_CPUPOOL_PAR_ANY : cpu;
>> -    return do_sysctl_save(xch, &sysctl);
>> +    for (retries = 0; retries < LIBXC_BUSY_RETRIES; retries++) {
> 
> Libxc coding style requires spaces between ().

Oops, sorry.

> 
>> +        err = do_sysctl_save(xch, &sysctl);
>> +        if (err >= 0 || errno != EBUSY)
> 
> Ditto.
> 
>> +            break;
>> +        sleep(1);
>> +    }
>> +    return err;
>>  }
>>  
>>  int xc_cpupool_movedomain(xc_interface *xch,


Juergen
diff mbox

Patch

diff --git a/tools/libxc/xc_cpupool.c b/tools/libxc/xc_cpupool.c
index c42273e..9f2f95c 100644
--- a/tools/libxc/xc_cpupool.c
+++ b/tools/libxc/xc_cpupool.c
@@ -20,8 +20,11 @@ 
  */
 
 #include <stdarg.h>
+#include <unistd.h>
 #include "xc_private.h"
 
+#define LIBXC_BUSY_RETRIES 5
+
 static int do_sysctl_save(xc_interface *xch, struct xen_sysctl *sysctl)
 {
     int ret;
@@ -141,13 +144,21 @@  int xc_cpupool_removecpu(xc_interface *xch,
                          uint32_t poolid,
                          int cpu)
 {
+    unsigned retries;
+    int err;
     DECLARE_SYSCTL;
 
     sysctl.cmd = XEN_SYSCTL_cpupool_op;
     sysctl.u.cpupool_op.op = XEN_SYSCTL_CPUPOOL_OP_RMCPU;
     sysctl.u.cpupool_op.cpupool_id = poolid;
     sysctl.u.cpupool_op.cpu = (cpu < 0) ? XEN_SYSCTL_CPUPOOL_PAR_ANY : cpu;
-    return do_sysctl_save(xch, &sysctl);
+    for (retries = 0; retries < LIBXC_BUSY_RETRIES; retries++) {
+        err = do_sysctl_save(xch, &sysctl);
+        if (err >= 0 || errno != EBUSY)
+            break;
+        sleep(1);
+    }
+    return err;
 }
 
 int xc_cpupool_movedomain(xc_interface *xch,