Commit fa3aa7a5 authored Mar 07, 2017 by Frederic Weisbecker Committed by Thomas Gleixner Mar 07, 2017

jiffies: Revert bogus conversion of NSEC_PER_SEC to TICK_NSEC



commit 93825f2e converted NSEC_PER_SEC to TICK_NSEC because the author
confused NSEC_PER_JIFFY with NSEC_PER_SEC.

As a result, the calculation of refined jiffies got broken, triggering
lockups.

Fixes: 93825f2e ("jiffies: Reuse TICK_NSEC instead of NSEC_PER_JIFFY")
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1488880534-3777-1-git-send-email-fweisbec@gmail.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent 25b68a8f

kernel/time/jiffies.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -125,7 +125,7 @@ int register_refined_jiffies(long cycles_per_second)
		shift_hz += cycles_per_tick/2;
		do_div(shift_hz, cycles_per_tick);
		/* Calculate nsec_per_tick using shift_hz */
		nsec_per_tick = (u64)TICK_NSEC << 8;
		nsec_per_tick = (u64)NSEC_PER_SEC << 8;
		nsec_per_tick += (u32)shift_hz/2;
		do_div(nsec_per_tick, (u32)shift_hz);

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