[PATCH] x86/cpuidle: publish new states only after fully initializing them

[PATCH] x86/cpuidle: publish new states only after fully initializing them

[Jan Beulich]

[-- Attachment #1: Type: text/plain, Size: 1180 bytes --]

Since state information coming from Dom0 can arrive at any time, on
any CPU, we ought to make sure that a new state is fully initialized
before the target CPU might be using it.

Once touching that code, also do minor cleanup: A missing (but benign)
"break" and some white space adjustments.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -912,7 +912,7 @@ static void set_cx(
                    acpi_power->cpu, xen_cx->type);
             return;
         }
-        cx = &acpi_power->states[acpi_power->count++];
+        cx = &acpi_power->states[acpi_power->count];
         cx->type = xen_cx->type;
         break;
     }
@@ -937,11 +937,14 @@ static void set_cx(
         break;
     default:
         cx->entry_method = ACPI_CSTATE_EM_NONE;
+        break;
     }
 
-    cx->latency  = xen_cx->latency;
-    
+    cx->latency = xen_cx->latency;
     cx->target_residency = cx->latency * latency_factor;
+
+    smp_wmb();
+    acpi_power->count++;
     if ( cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 )
         acpi_power->safe_state = cx;
 }




[-- Attachment #2: x86-cpuidle-set_cx.patch --]
[-- Type: text/plain, Size: 1244 bytes --]

x86/cpuidle: publish new states only after fully initializing them

Since state information coming from Dom0 can arrive at any time, on
any CPU, we ought to make sure that a new state is fully initialized
before the target CPU might be using it.

Once touching that code, also do minor cleanup: A missing (but benign)
"break" and some white space adjustments.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -912,7 +912,7 @@ static void set_cx(
                    acpi_power->cpu, xen_cx->type);
             return;
         }
-        cx = &acpi_power->states[acpi_power->count++];
+        cx = &acpi_power->states[acpi_power->count];
         cx->type = xen_cx->type;
         break;
     }
@@ -937,11 +937,14 @@ static void set_cx(
         break;
     default:
         cx->entry_method = ACPI_CSTATE_EM_NONE;
+        break;
     }
 
-    cx->latency  = xen_cx->latency;
-    
+    cx->latency = xen_cx->latency;
     cx->target_residency = cx->latency * latency_factor;
+
+    smp_wmb();
+    acpi_power->count++;
     if ( cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 )
         acpi_power->safe_state = cx;
 }

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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

Re: [PATCH] x86/cpuidle: publish new states only after fully initializing them

[Andrew Cooper]

[-- Attachment #1.1: Type: text/plain, Size: 1448 bytes --]

On 10/12/13 15:26, Jan Beulich wrote:
> Since state information coming from Dom0 can arrive at any time, on
> any CPU, we ought to make sure that a new state is fully initialized
> before the target CPU might be using it.
>
> Once touching that code, also do minor cleanup: A missing (but benign)
> "break" and some white space adjustments.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>
> --- a/xen/arch/x86/acpi/cpu_idle.c
> +++ b/xen/arch/x86/acpi/cpu_idle.c
> @@ -912,7 +912,7 @@ static void set_cx(
>                     acpi_power->cpu, xen_cx->type);
>              return;
>          }
> -        cx = &acpi_power->states[acpi_power->count++];
> +        cx = &acpi_power->states[acpi_power->count];
>          cx->type = xen_cx->type;
>          break;
>      }
> @@ -937,11 +937,14 @@ static void set_cx(
>          break;
>      default:
>          cx->entry_method = ACPI_CSTATE_EM_NONE;
> +        break;
>      }
>  
> -    cx->latency  = xen_cx->latency;
> -    
> +    cx->latency = xen_cx->latency;
>      cx->target_residency = cx->latency * latency_factor;
> +
> +    smp_wmb();
> +    acpi_power->count++;
>      if ( cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 )
>          acpi_power->safe_state = cx;
>  }
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


[-- Attachment #1.2: Type: text/html, Size: 2364 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

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

Re: [PATCH] x86/cpuidle: publish new states only after fully initializing them

[Liu, Jinsong]

Jan Beulich wrote:
> Since state information coming from Dom0 can arrive at any time, on
> any CPU, we ought to make sure that a new state is fully initialized
> before the target CPU might be using it.
> 
> Once touching that code, also do minor cleanup: A missing (but benign)
> "break" and some white space adjustments.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 

Reviewed-by: Liu Jinsong <jinsong.liu@intel.com>