Re: [Qemu-devel] [RFC PATCH v2 1/9] exec: Remove cpu from cpus list during cpu_exec_exit()

[Thomas Huth]

On 11.03.2016 05:54, Bharata B Rao wrote:
> CPUState *cpu gets added to the cpus list during cpu_exec_init(). It
> should be removed from cpu_exec_exit().
> 
> cpu_exec_exit() is called from generic CPU::instance_finalize and some
> archs like PowerPC call it from CPU unrealizefn. So ensure that we
> dequeue the cpu only once.
> 
> Now -1 value for cpu->cpu_index indicates that we have already dequeued
> the cpu for CONFIG_USER_ONLY case also.
> 
> Signed-off-by: Bharata B Rao 
> Reviewed-by: David Gibson 
> ---
>  exec.c | 32 
>  1 file changed, 24 insertions(+), 8 deletions(-)
> 
> diff --git a/exec.c b/exec.c
> index f09dd4e..49ae593 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -609,15 +609,9 @@ static int cpu_get_free_index(Error **errp)
>  return cpu;
>  }
>  
> -void cpu_exec_exit(CPUState *cpu)
> +static void cpu_release_index(CPUState *cpu)
>  {
> -if (cpu->cpu_index == -1) {
> -/* cpu_index was never allocated by this @cpu or was already freed. 
> */
> -return;
> -}
> -
>  bitmap_clear(cpu_index_map, cpu->cpu_index, 1);
> -cpu->cpu_index = -1;
>  }
>  #else
>  
> @@ -632,11 +626,33 @@ static int cpu_get_free_index(Error **errp)
>  return cpu_index;
>  }
>  
> -void cpu_exec_exit(CPUState *cpu)
> +static void cpu_release_index(CPUState *cpu)
>  {
> +return;
>  }
>  #endif
>  
> +void cpu_exec_exit(CPUState *cpu)
> +{
> +#if defined(CONFIG_USER_ONLY)
> +cpu_list_lock();
> +#endif
> +if (cpu->cpu_index == -1) {
> +/* cpu_index was never allocated by this @cpu or was already freed. 
> */
> +#if defined(CONFIG_USER_ONLY)
> +cpu_list_unlock();
> +#endif
> +return;
> +}
> +
> +QTAILQ_REMOVE(, cpu, node);
> +cpu_release_index(cpu);
> +cpu->cpu_index = -1;
> +#if defined(CONFIG_USER_ONLY)
> +cpu_list_unlock();
> +#endif
> +}
> +
>  void cpu_exec_init(CPUState *cpu, Error **errp)
>  {
>  CPUClass *cc = CPU_GET_CLASS(cpu);
> 

Reviewed-by: Thomas Huth 

[Qemu-devel] [RFC PATCH v2 1/9] exec: Remove cpu from cpus list during cpu_exec_exit()

[Bharata B Rao]

CPUState *cpu gets added to the cpus list during cpu_exec_init(). It
should be removed from cpu_exec_exit().

cpu_exec_exit() is called from generic CPU::instance_finalize and some
archs like PowerPC call it from CPU unrealizefn. So ensure that we
dequeue the cpu only once.

Now -1 value for cpu->cpu_index indicates that we have already dequeued
the cpu for CONFIG_USER_ONLY case also.

Signed-off-by: Bharata B Rao 
Reviewed-by: David Gibson 
---
 exec.c | 32 
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/exec.c b/exec.c
index f09dd4e..49ae593 100644
--- a/exec.c
+++ b/exec.c
@@ -609,15 +609,9 @@ static int cpu_get_free_index(Error **errp)
 return cpu;
 }
 
-void cpu_exec_exit(CPUState *cpu)
+static void cpu_release_index(CPUState *cpu)
 {
-if (cpu->cpu_index == -1) {
-/* cpu_index was never allocated by this @cpu or was already freed. */
-return;
-}
-
 bitmap_clear(cpu_index_map, cpu->cpu_index, 1);
-cpu->cpu_index = -1;
 }
 #else
 
@@ -632,11 +626,33 @@ static int cpu_get_free_index(Error **errp)
 return cpu_index;
 }
 
-void cpu_exec_exit(CPUState *cpu)
+static void cpu_release_index(CPUState *cpu)
 {
+return;
 }
 #endif
 
+void cpu_exec_exit(CPUState *cpu)
+{
+#if defined(CONFIG_USER_ONLY)
+cpu_list_lock();
+#endif
+if (cpu->cpu_index == -1) {
+/* cpu_index was never allocated by this @cpu or was already freed. */
+#if defined(CONFIG_USER_ONLY)
+cpu_list_unlock();
+#endif
+return;
+}
+
+QTAILQ_REMOVE(, cpu, node);
+cpu_release_index(cpu);
+cpu->cpu_index = -1;
+#if defined(CONFIG_USER_ONLY)
+cpu_list_unlock();
+#endif
+}
+
 void cpu_exec_init(CPUState *cpu, Error **errp)
 {
 CPUClass *cc = CPU_GET_CLASS(cpu);
-- 
2.1.0