From: Ray Lee <ray-lk@madrabbit.org>
To: Pavel Emelyanov <xemul@openvz.org>
Cc: Kirill Korotaev <dev@parallels.com>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Kirill Korotaev <dev@openvz.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [git pull] timer fix
Date: Thu, 5 Feb 2009 08:04:15 -0800 [thread overview]
Message-ID: <2c0942db0902050804w2e1adc12hbeae29582e5f7193@mail.gmail.com> (raw)
In-Reply-To: <498AB837.1040404@openvz.org>
On Thu, Feb 5, 2009 at 1:58 AM, Pavel Emelyanov <xemul@openvz.org> wrote:
> Kirill Korotaev wrote:
>> ACK, it works. Why not save another 4 bytes of .bss then by changing
>> hept_t1_cmp to u32? ;-)
>
> Hm... .bss you say? :) The bloat-o-meter results would be:
>
> For the original fix with casting hpet_t1_cmp to u32 inside the loop
> add/remove: 0/0 grow/shrink: 1/0 up/down: 2/0 (2)
> function old new delta
> hpet_rtc_interrupt 741 743 +2
>
> For the fix with casting the substitution result to s32
> add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-2 (-2)
> function old new delta
> hpet_rtc_interrupt 741 739 -2
>
> For the proposed by Kirill type change of the hpet_t1_cmp
> add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-6 (-6)
> function old new delta
> hpet_rtc_timer_init 186 185 -1
> hpet_rtc_interrupt 741 740 -1
> hpet_t1_cmp 8 4 -4
>
> That's the fix:
>
> diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
> index 64d5ad0..dfbbb94 100644
> --- a/arch/x86/kernel/hpet.c
> +++ b/arch/x86/kernel/hpet.c
> @@ -897,7 +897,7 @@ static unsigned long hpet_rtc_flags;
> static int hpet_prev_update_sec;
> static struct rtc_time hpet_alarm_time;
> static unsigned long hpet_pie_count;
> -static unsigned long hpet_t1_cmp;
> +static u32 hpet_t1_cmp;
> static unsigned long hpet_default_delta;
> static unsigned long hpet_pie_delta;
> static unsigned long hpet_pie_limit;
>
> Reported-by: Kirill Korotaev <dev@openvz.org>
> Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
>
> This one also works. Should I re-send this patch in a proper way?
Ugh. This version seems too subtle for a new reader coming into this
code. I'd prefer the fix be kept in the comparison site, where people
already expect wraparound issues.
If you don't have time to add the helper, I'd really rather see the
version with the explicit cast acting as documentation, rather than a
test that magically works due to type issues.
Dunno, maybe it's just me.
next prev parent reply other threads:[~2009-02-05 16:04 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-04 19:25 [git pull] timer fix Ingo Molnar
2009-02-04 22:11 ` Linus Torvalds
2009-02-04 22:16 ` Linus Torvalds
2009-02-04 22:25 ` Ingo Molnar
2009-02-04 22:58 ` Ingo Molnar
2009-02-04 23:13 ` H. Peter Anvin
2009-02-05 0:04 ` Ingo Molnar
2009-02-05 7:51 ` Kirill Korotaev
2009-02-05 9:58 ` Pavel Emelyanov
2009-02-05 14:30 ` Ingo Molnar
2009-02-05 16:04 ` Ray Lee [this message]
2009-02-17 16:38 Ingo Molnar
2009-06-20 16:55 [GIT PULL] " Ingo Molnar
2009-08-04 19:04 Ingo Molnar
2009-08-09 16:09 Ingo Molnar
2009-09-26 12:27 Ingo Molnar
2009-10-02 12:38 Ingo Molnar
2010-01-31 17:26 Ingo Molnar
2011-02-15 17:06 Ingo Molnar
2011-02-28 17:39 Ingo Molnar
2011-04-29 18:11 Ingo Molnar
2011-10-17 1:39 Linux 3.1-rc9 Linus Torvalds
2011-10-17 10:34 ` Peter Zijlstra
2011-10-17 14:57 ` Linus Torvalds
2011-10-17 17:54 ` Peter Zijlstra
2011-10-17 18:31 ` Linus Torvalds
2011-10-17 19:23 ` Peter Zijlstra
2011-10-17 21:00 ` Thomas Gleixner
2011-10-18 8:39 ` Thomas Gleixner
2011-10-18 9:05 ` Peter Zijlstra
2011-10-18 14:59 ` Linus Torvalds
2011-10-18 18:14 ` [GIT PULL] timer fix Ingo Molnar
2013-09-18 16:22 Ingo Molnar
2013-10-26 12:27 Ingo Molnar
2014-01-15 18:27 Ingo Molnar
2014-03-29 18:44 Ingo Molnar
2015-02-06 18:38 Ingo Molnar
2015-07-18 3:06 Ingo Molnar
2015-08-14 7:13 Ingo Molnar
2016-04-23 11:34 Ingo Molnar
2016-07-13 12:58 Ingo Molnar
2016-10-18 11:18 Ingo Molnar
2016-12-23 22:53 Ingo Molnar
2017-01-18 9:37 Ingo Molnar
2017-05-12 7:35 Ingo Molnar
2017-07-21 10:21 Ingo Molnar
2017-08-26 7:17 Ingo Molnar
2017-09-24 11:25 Ingo Molnar
2018-03-25 9:00 Ingo Molnar
2018-12-21 12:34 Ingo Molnar
2018-12-21 19:30 ` pr-tracker-bot
2018-12-23 19:29 ` Heiko Carstens
2019-01-17 9:51 ` Ingo Molnar
2019-01-17 15:58 ` Heiko Carstens
2019-01-17 16:57 ` Thomas Gleixner
2019-04-12 13:09 Ingo Molnar
2019-04-13 4:05 ` pr-tracker-bot
2019-09-26 20:18 Ingo Molnar
2019-09-26 23:00 ` pr-tracker-bot
2019-10-02 22:06 Ingo Molnar
2019-10-02 23:00 ` pr-tracker-bot
2019-11-16 21:38 Ingo Molnar
2019-11-17 0:35 ` pr-tracker-bot
2020-04-25 10:16 Ingo Molnar
2020-04-25 19:30 ` pr-tracker-bot
2020-06-28 18:39 Ingo Molnar
2020-06-28 22:05 ` pr-tracker-bot
2024-05-10 11:12 Ingo Molnar
2024-05-10 17:29 ` pr-tracker-bot
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