Re: [Qemu-devel] [RFC PATCH V6 18/18] translate-all: (wip) use tb_flush_safe when we can't alloc more tb.

[Frederic Konrad]

On 07/07/2015 18:17, Alex Bennée wrote:
> address@hidden writes:
>
> > From: KONRAD Frederic <address@hidden>
> >
> > This changes just the tb_flush called from tb_alloc.
> >
> > TODO:
> >   * changes the other tb_flush.
> >
> > Signed-off-by: KONRAD Frederic <address@hidden>
> > ---
> >   translate-all.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/translate-all.c b/translate-all.c
> > index 8bd8fe8..9adaffa 100644
> > --- a/translate-all.c
> > +++ b/translate-all.c
> > @@ -1147,7 +1147,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> >       tb = tb_alloc(pc);
> >       if (!tb) {
> >           /* flush must be done */
> > -        tb_flush(env);
> > +        tb_flush_safe(env);
> Hold on this is async right? What stops us rolling on and then getting
> flushed when the other vCPUs come to a halt?
>
> It deserves a comment at least.

not this need some synchronization when the CPUs are halted.
There is crap here spotted by Paolo though.

In the case of tb_flush.. We do an async_safe_work because all VCPUs thread
must be outside cpu_exec.

Are you suggesting to just exiting everybody and wait here that all 
VCPUs exit?
This is possible as well here but is not possible for the other case.. 
That's why I
prefered a "generic" mechanism.

Fred
> >           /* cannot fail at this point */
> >           tb = tb_alloc(pc);
> >           /* Don't forget to invalidate previous TB info.  */