From: Paolo Bonzini <pbonzini@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Daniel P. Berrange" <berrange@redhat.com>
Cc: Michal Privoznik <mprivozn@redhat.com>,
Jitendra Kolhe <jitendra.kolhe@hpe.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] os: don't corrupt pre-existing memory-backend data with prealloc
Date: Fri, 24 Feb 2017 13:18:22 +0100 [thread overview]
Message-ID: <64d3da43-9ff6-e448-fb40-13fbe367e27a@redhat.com> (raw)
In-Reply-To: <20170224121217.GH2435@work-vm>
On 24/02/2017 13:12, Dr. David Alan Gilbert wrote:
>> Ok, yeah, it makes sense that the compiler can optimize that away without
>> volatile. I wonder if adding volatile has much of a performance impact on
>> this loop...
> I don't think we have anything else in QEMU to do it (other than atomic's
> but we don't need this to be atomic). I don't think the use of memset()
> helps, because the compiler is free to optimise that out as well; so
> I think 'volatile' is a reasonable use (although I seem to have a soft-spot
> for volatile and I know everyone else tells me I'm mad).
Yes, I think it is fine to use volatile here.
Paolo
next prev parent reply other threads:[~2017-02-24 12:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-23 10:59 [Qemu-devel] [PATCH] os: don't corrupt pre-existing memory-backend data with prealloc Daniel P. Berrange
2017-02-23 12:05 ` Michal Privoznik
2017-02-23 12:07 ` Daniel P. Berrange
2017-02-24 9:05 ` Michal Privoznik
2017-02-24 9:24 ` Daniel P. Berrange
2017-02-24 12:12 ` Dr. David Alan Gilbert
2017-02-24 12:18 ` Paolo Bonzini [this message]
2017-02-27 11:10 ` Stefan Hajnoczi
2017-02-27 13:46 ` Rik van Riel
2017-02-27 13:58 ` Daniel P. Berrange
-- strict thread matches above, loose matches on Subject: below --
2017-02-24 17:27 Daniel P. Berrange
2017-02-24 17:33 ` no-reply
2017-02-27 9:25 ` Daniel P. Berrange
2017-02-24 19:04 ` Eric Blake
2017-02-27 13:28 ` Stefan Hajnoczi
2017-02-27 15:53 ` Andrea Arcangeli
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