timekeeping/clocksource_cyc2ns: Document intended range limitation

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The "cycles" argument should not be an absolute clocksource cycle
value, as the implementation's arithmetic will overflow relatively
easily with wide (64 bit) clocksource counters.

For performance, the implementation is simple and fast, since the
function is intended for only relatively small delta values of
clocksource cycles.

[jstultz: Fixed up to merge against HEAD & commit message tweaks,
 also included rewording suggestion by Ingo]
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Link: http://lkml.kernel.org/r/1480372524-15181-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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Chris Metcalf 2016-11-28 14:35:20 -08:00 • committed by Thomas Gleixner

parent ba58d1020a

commit ec4101e890

1 changed files with 4 additions and 1 deletions

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include/linux/clocksource.h

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