From: Sergey Fedorov <serge.fdrv@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sergey Fedorov <sergey.fedorov@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
Richard Henderson <rth@twiddle.net>,
Peter Crosthwaite <crosthwaite.peter@gmail.com>
Cc: "Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: [Qemu-devel] tcg: reworking tb_invalidated_flag
Date: Thu, 31 Mar 2016 16:14:13 +0300 [thread overview]
Message-ID: <56FD22A5.10501@gmail.com> (raw)
In-Reply-To: <56FC174A.6070906@redhat.com>
On 30/03/16 21:13, Paolo Bonzini wrote:
>
> On 30/03/2016 19:08, Sergey Fedorov wrote:
>> The second approach is to make 'tb_invalidated_flag' per-CPU. This
>> would be conceptually similar to what we have, but would give us thread
>> safety. With this approach, we need to be careful to correctly clear and
>> set the flag.
> You can just ensure that setting and clearing it is done under tb_lock.
So it could remain sitting in 'tcg_ctx.tb_ctx'. I'm just wondering what
could be real benefits for making it per-CPU then?
> Because TranslationBlocks live in tcg_ctx.tb_ctx.tbs you need
> special code to exit all CPUs at tb_flush time, otherwise you risk that
> a tb_alloc reuses a TranslationBlock while it is in use by a VCPU.
Looks like no matter which approach we use, it's ultimately necessary to
ensure all CPUs have exited from translated code before the translation
buffer may be safely flushed.
Kind regards,
Sergey
next prev parent reply other threads:[~2016-03-31 13:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-30 17:08 [Qemu-devel] tcg: reworking tb_invalidated_flag Sergey Fedorov
2016-03-30 18:13 ` Paolo Bonzini
2016-03-31 13:14 ` Sergey Fedorov [this message]
2016-03-31 13:37 ` Alex Bennée
2016-03-31 14:06 ` Sergey Fedorov
2016-03-31 19:03 ` Sergey Fedorov
2016-03-31 19:56 ` Paolo Bonzini
2016-04-01 11:11 ` Alex Bennée
2016-04-01 11:23 ` Sergey Fedorov
2016-03-31 13:40 ` Paolo Bonzini
2016-03-31 14:35 ` Sergey Fedorov
2016-03-31 14:44 ` Paolo Bonzini
2016-03-30 19:08 ` Richard Henderson
2016-03-30 21:21 ` Sergey Fedorov
2016-03-31 10:48 ` Alex Bennée
2016-03-31 12:42 ` Sergey Fedorov
2016-03-31 16:25 ` Richard Henderson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56FD22A5.10501@gmail.com \
--to=serge.fdrv@gmail.com \
--cc=alex.bennee@linaro.org \
--cc=crosthwaite.peter@gmail.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rth@twiddle.net \
--cc=sergey.fedorov@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.