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Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup |
Date: |
Tue, 19 Jul 2016 18:27:42 -0400 (EDT) |
----- Original Message -----
> From: "Sergey Fedorov" <address@hidden>
> To: "Paolo Bonzini" <address@hidden>, address@hidden
> Cc: "sergey fedorov" <address@hidden>, "alex bennee" <address@hidden>
> Sent: Tuesday, July 19, 2016 9:56:49 PM
> Subject: Re: [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup
>
> On 19/07/16 11:32, Paolo Bonzini wrote:
> >
>
> It looks much better now :)
>
> > When invalidating a translation block, set an invalid flag into the
> > TranslationBlock structure first. It is also necessary to check whether
> > the target TB is still valid after acquiring 'tb_lock' but before calling
> > tb_add_jump() since TB lookup is to be performed out of 'tb_lock' in
> > future. Note that we don't have to check 'last_tb'; an already invalidated
> > TB will not be executed anyway and it is thus safe to patch it.
> >
> > Suggested-by: Sergey Fedorov <address@hidden>
> > Signed-off-by: Paolo Bonzini <address@hidden>
> > ---
> > cpu-exec.c | 5 +++--
> > include/exec/exec-all.h | 2 ++
> > translate-all.c | 3 +++
> > 3 files changed, 8 insertions(+), 2 deletions(-)
> (snip)
> > diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> > index acda7b6..bc0bcc5 100644
> > --- a/include/exec/exec-all.h
> > +++ b/include/exec/exec-all.h
> > @@ -213,6 +213,8 @@ struct TranslationBlock {
> > #define CF_USE_ICOUNT 0x20000
> > #define CF_IGNORE_ICOUNT 0x40000 /* Do not generate icount code */
> >
> > + uint16_t invalid;
>
> Why not "int"?
There's a hole there, we may want to move something else so I
used a smaller data type. Even uint8_t would do.
Paolo
>
> > +
> > void *tc_ptr; /* pointer to the translated code */
> > uint8_t *tc_search; /* pointer to search data */
> > /* original tb when cflags has CF_NOCACHE */
> >
>
> Thanks,
> Sergey
>
[Qemu-devel] [PATCH 03/10] tcg: Prepare safe tb_jmp_cache lookup out of tb_lock, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 04/10] tcg: Prepare safe access to tb_flushed out of tb_lock, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 06/10] tcg: set up tb->page_addr before insertion, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 08/10] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 10/10] tcg: rename tb_find_physical(), Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 09/10] tcg: Merge tb_find_slow() and tb_find_fast(), Paolo Bonzini, 2016/07/19