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From: Peter Maydell <peter.maydell@linaro.org>
To: Richard Henderson <rth@twiddle.net>
Cc: QEMU Developers <qemu-devel@nongnu.org>,
	Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [PATCH for-2.5] tcg: Increase the highwater reservation
Date: Tue, 1 Dec 2015 16:28:55 +0000	[thread overview]
Message-ID: <CAFEAcA92UH3H8qrm_Re6qN94WvGML18K+c=CV8DvPHH1FSy31g@mail.gmail.com> (raw)
In-Reply-To: <1448986767-28016-1-git-send-email-rth@twiddle.net>

On 1 December 2015 at 16:19, Richard Henderson <rth@twiddle.net> wrote:
> If there are a lot of guest memory ops in the TB, the amount of
> code generated by tcg_out_tb_finalize could be well more than 1k.
> In the short term, increase the reservation larger than any TB
> seen in practice.
>
> Reported-by: Aurelien Jarno <aurelien@aurel32.net>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>
> Reported and discussed with Aurelien on IRC yesterday.  This seems
> to be the easiest fix for the upcoming release.  I will fix this
> properly (by modifying every backend's finalize routines) for 2.6.

What would be the result of our hitting this bug? I ask because
there's a report on qemu-discuss about a qemu-i386-on-ARM-host
bug: http://lists.nongnu.org/archive/html/qemu-discuss/2015-11/msg00042.html
and the debug log (http://www.mediafire.com/download/ge611be9vbebbw7/qemu.log)
suggests we're segfaulting in translation on the TB shortly
after we (successfully) translate a TB whose final 'out' size
is 1100 and which has 64 guest writes in it. So I'm wondering
if that's actually the same bug this is fixing...

thanks
-- PMM

  reply	other threads:[~2015-12-01 16:29 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-01 16:19 [Qemu-devel] [PATCH for-2.5] tcg: Increase the highwater reservation Richard Henderson
2015-12-01 16:28 ` Peter Maydell [this message]
2015-12-01 16:34   ` Aurelien Jarno
2015-12-01 16:40     ` Aurelien Jarno
2015-12-01 23:06       ` Richard Henderson
2015-12-01 23:20         ` Peter Maydell
2015-12-01 16:46   ` Richard Henderson
2015-12-01 16:32 ` Aurelien Jarno
2015-12-02 18:36   ` Richard Henderson
2015-12-03 12:19     ` Aurelien Jarno
2015-12-04  8:36       ` Aurelien Jarno

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