From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Bligh <alex@alex.org.uk>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 5/8] timers: prepare the code for future races in calling qemu_clock_warp
Date: Tue, 08 Oct 2013 18:56:43 +0200 [thread overview]
Message-ID: <5254394B.506@redhat.com> (raw)
In-Reply-To: <703C02BF-B3A3-493A-8713-7979746C6811@alex.org.uk>
Il 08/10/2013 18:54, Alex Bligh ha scritto:
>> > -
>> > - /* Maintain prior (possibly buggy) behaviour where if no deadline
>> > - * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
>> > - * INT32_MAX nanoseconds ahead, we still use INT32_MAX
>> > - * nanoseconds.
>> > - */
>> > - if ((deadline < 0) || (deadline > INT32_MAX)) {
>> > - deadline = INT32_MAX;
>> > + if (deadline < 0) {
>> > + return;
>> > }
>
> Arguably the patch could document why removing the check for deadline > INT32_MAX
> (the bug for bug compatibility) is safe, as I couldn't entirely convince myself it
> was, mostly because I couldn't see why it was doing it in the first place.
I couldn't convince myself that it is _not_ safe :) and it made the code
more complicated. As soon as a deadline appears, qemu_clock_warp() will
be called again and update the icount_warp_timer.
Ok to move that to a separate patch?
Paolo
next prev parent reply other threads:[~2013-10-08 16:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-08 8:47 [Qemu-devel] [PATCH 0/8] Make icount thread-safe Paolo Bonzini
2013-10-08 8:47 ` [Qemu-devel] [PATCH 1/8] timers: extract timer_mod_ns_locked and timerlist_rearm Paolo Bonzini
2013-10-08 9:06 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 2/8] timers: add timer_mod_anticipate and timer_mod_anticipate_ns Paolo Bonzini
2013-10-08 9:15 ` Alex Bligh
2013-10-08 9:25 ` Paolo Bonzini
2013-10-08 17:01 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 3/8] timers: use cpu_get_icount() directly Paolo Bonzini
2013-10-08 16:49 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 4/8] timers: reorganize icount_warp_rt Paolo Bonzini
2013-10-08 16:50 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 5/8] timers: prepare the code for future races in calling qemu_clock_warp Paolo Bonzini
2013-10-08 16:54 ` Alex Bligh
2013-10-08 16:56 ` Paolo Bonzini [this message]
2013-10-08 17:08 ` Alex Bligh
2013-10-08 17:10 ` Paolo Bonzini
2013-10-08 8:47 ` [Qemu-devel] [PATCH 6/8] timers: introduce cpu_get_clock_locked Paolo Bonzini
2013-10-08 16:55 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 7/8] timers: document (future) locking rules for icount Paolo Bonzini
2013-10-08 16:56 ` Alex Bligh
2013-10-08 8:47 ` [Qemu-devel] [PATCH 8/8] timers: make icount thread-safe Paolo Bonzini
2013-10-08 16:57 ` Alex Bligh
2013-10-08 13:47 ` [Qemu-devel] [PATCH 0/8] Make " Andreas Färber
2013-10-08 13:55 ` Paolo Bonzini
2013-11-05 9:27 ` Stefan Hajnoczi
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