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From: Richard Cochran <richardcochran@gmail.com>
To: John Stultz <john.stultz@linaro.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Dave Jones <davej@codemonkey.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Prarit Bhargava <prarit@redhat.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 06/10] time: Cap clocksource reads to the clocksource max_cycles value
Date: Sun, 11 Jan 2015 13:41:46 +0100	[thread overview]
Message-ID: <20150111124146.GA15387@localhost.localdomain> (raw)
In-Reply-To: <1420850068-27828-7-git-send-email-john.stultz@linaro.org>

On Fri, Jan 09, 2015 at 04:34:24PM -0800, John Stultz wrote:
> When calculating the current delta since the last tick, we
> currently have no hard protections to prevent a multiplciation
> overflow from ocurring.

This is just papering over the problem. The "hard protection" should
be having a tick scheduled before the range of the clock source is
exhausted.

Thanks,
Richard

  reply	other threads:[~2015-01-11 12:41 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-10  0:34 [PATCH 00/10][RFC] Increased clocksource validation and cleanups John Stultz
2015-01-10  0:34 ` [PATCH 01/10] clocksource: Simplify clocks_calc_max_nsecs logic John Stultz
2015-01-10  0:34 ` [PATCH 02/10] clocksource: Simplify logic around clocksource wrapping saftey margins John Stultz
2015-01-10  2:03   ` Stephen Boyd
2015-01-10  0:34 ` [PATCH 03/10] clocksource: Remove clocksource_max_deferment() John Stultz
2015-01-11 11:47   ` Richard Cochran
2015-01-12 18:36     ` John Stultz
2015-01-12 20:16       ` Richard Cochran
2015-01-10  0:34 ` [PATCH 04/10] clocksource: Add max_cycles to clocksource structure John Stultz
2015-01-10  2:06   ` Stephen Boyd
2015-01-10  0:34 ` [PATCH 05/10] time: Add debugging checks to warn if we see delays John Stultz
2015-01-10  0:34 ` [PATCH 06/10] time: Cap clocksource reads to the clocksource max_cycles value John Stultz
2015-01-11 12:41   ` Richard Cochran [this message]
2015-01-12 18:54     ` John Stultz
2015-01-12 19:02       ` Linus Torvalds
2015-01-12 20:37         ` Richard Cochran
2015-01-12 20:30       ` Richard Cochran
2015-01-12 20:49         ` Richard Cochran
2015-01-13 11:11   ` Peter Zijlstra
2015-01-13 21:33     ` John Stultz
2015-01-13 22:51       ` Linus Torvalds
2015-01-14  9:35       ` Peter Zijlstra
2015-01-22 20:55         ` John Stultz
2015-01-10  0:34 ` [PATCH 07/10] time: Try to catch clocksource delta underflows John Stultz
2015-01-10  0:34 ` [PATCH 08/10] clocksource: Mostly kill clocksource_register() John Stultz
2015-01-10  0:34 ` [PATCH 09/10] sparc: Convert to using clocksource_register_hz() John Stultz
2015-01-10  0:34 ` [PATCH 10/10] clocksource: Add some debug info about clocksources being registered John Stultz
2015-01-10  2:02   ` Stephen Boyd
2015-01-22  0:51     ` John Stultz
2015-01-22 12:27       ` Prarit Bhargava
2015-01-11 11:41 ` [PATCH 00/10][RFC] Increased clocksource validation and cleanups Richard Cochran
2015-01-12 18:22   ` John Stultz
2015-01-12 20:45     ` Richard Cochran

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