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Re: [Qemu-devel] [RFC v2 11/11] tcg: Make tb_flush() thread safe
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [RFC v2 11/11] tcg: Make tb_flush() thread safe |
Date: |
Thu, 14 Jul 2016 09:41:58 +0100 |
User-agent: |
mu4e 0.9.17; emacs 25.0.95.9 |
Sergey Fedorov <address@hidden> writes:
> From: Sergey Fedorov <address@hidden>
>
> Use async_safe_run_on_cpu() to make tb_flush() thread safe.
>
> Signed-off-by: Sergey Fedorov <address@hidden>
> Signed-off-by: Sergey Fedorov <address@hidden>
> ---
>
> Changes in v2:
> - stale comment about unsafe tb_flush() removed
> ---
> translate-all.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/translate-all.c b/translate-all.c
> index eaa95e4cd7dc..e69b5d4e889e 100644
> --- a/translate-all.c
> +++ b/translate-all.c
> @@ -831,8 +831,7 @@ static void page_flush_tb(void)
> }
>
> /* flush all the translation blocks */
> -/* XXX: tb_flush is currently not thread safe */
> -void tb_flush(CPUState *cpu)
> +static void do_tb_flush(CPUState *cpu, void *data)
> {
> #if defined(DEBUG_FLUSH)
> printf("qemu: flush code_size=%ld nb_tbs=%d avg_tb_size=%ld\n",
> @@ -861,6 +860,11 @@ void tb_flush(CPUState *cpu)
> tcg_ctx.tb_ctx.tb_flush_count++;
> }
>
> +void tb_flush(CPUState *cpu)
> +{
> + async_safe_run_on_cpu(cpu, do_tb_flush, NULL);
> +}
> +
> #ifdef DEBUG_TB_CHECK
>
> static void
> @@ -1163,9 +1167,8 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> buffer_overflow:
> /* flush must be done */
> tb_flush(cpu);
> - /* cannot fail at this point */
> - tb = tb_alloc(pc);
> - assert(tb != NULL);
> + mmap_unlock();
> + cpu_loop_exit(cpu);
Given our other discussions about lock resetting I wonder if this is
another case where mmap_reset() could be called on cpu_loop_exit?
> }
>
> gen_code_buf = tcg_ctx.code_gen_ptr;
Otherwise so far the testing is looking pretty positive in linux-user:
Tested-by: Alex Bennée <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
--
Alex Bennée
- [Qemu-devel] [RFC v2 07/11] linux-user: Rework exclusive operation mechanism, (continued)
- [Qemu-devel] [RFC v2 07/11] linux-user: Rework exclusive operation mechanism, Sergey Fedorov, 2016/07/06
- [Qemu-devel] [RFC v2 06/11] linux-user: Use QemuMutex and QemuCond, Sergey Fedorov, 2016/07/06
- [Qemu-devel] [RFC v2 08/11] linux-user: Add qemu_cpu_is_self() and qemu_cpu_kick(), Sergey Fedorov, 2016/07/06
- [Qemu-devel] [RFC v2 10/11] cpu-exec-common: Introduce async_safe_run_on_cpu(), Sergey Fedorov, 2016/07/06
- [Qemu-devel] [RFC v2 11/11] tcg: Make tb_flush() thread safe, Sergey Fedorov, 2016/07/06
- [Qemu-devel] [RFC v2 09/11] linux-user: Support CPU work queue, Sergey Fedorov, 2016/07/06
- Re: [Qemu-devel] [RFC v2 00/11] cpu-exec: Safe work in quiescent state, Alex Bennée, 2016/07/14