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Re: [Qemu-devel] [RFC PATCH v1 01/10] exec: Remove cpu from cpus list du
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [RFC PATCH v1 01/10] exec: Remove cpu from cpus list during cpu_exec_exit() |
Date: |
Mon, 7 Mar 2016 17:23:48 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 04.03.2016 07:54, 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_init() is called from generic CPU::instance_finalize and some
s/cpu_exec_init/cpu_exec_exit/
> 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 <address@hidden>
> ---
> exec.c | 32 ++++++++++++++++++++++++--------
> 1 file changed, 24 insertions(+), 8 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index c62c439..7c3f747 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -588,15 +588,9 @@ 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
>
> @@ -611,11 +605,33 @@ 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;
You could also simply leave that return statement away, I think.
> }
> #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(&cpus, cpu, node);
> + cpu_release_index(cpu);
> + cpu->cpu_index = -1;
> +#if defined(CONFIG_USER_ONLY)
> + cpu_list_unlock();
> +#endif
> +}
Since there are a couple of these
#if defined(CONFIG_USER_ONLY)
cpu_list_[un]lock();
#endif
in exec.c already, it might be somewhat nices to declare them at the
beginning of the file as empty functions, somewhat like:
#if !defined(CONFIG_USER_ONLY)
static inline void cpu_list_lock(void)
{
}
static inline void cpu_list_unlock(void)
{
}
#endif
What do you think about that?
Apart from that, the patch looks fine to me.
Thomas