Messages in this thread Patch in this message | | | From | Santosh Shilimkar <> | Subject | [PATCH] sched_clock: fix postinit no sched_clock function check | Date | Wed, 2 Oct 2013 12:55:28 -0400 |
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The sched_clock code uses 2 levels of function pointers, sched_clock_func() and read_sched_clock() but the no sched_clock check in postinit() just checks read_sched_clock().
This leads to kernel falling back to jiffy based sched clock even in presence of sched_clock_func() which is not desirable.
Fix the postinit() check to avoid the issue. Probably the issue is hidden so far on most of the arm SOCs because of already existing sched_clock registrations apart from arch_timer sched_clock. One can reproduce the issue by just have arch_timer as sched_clock
Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> --- kernel/time/sched_clock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 0b479a6..15c4d78 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -179,7 +179,8 @@ void __init sched_clock_postinit(void) * If no sched_clock function has been provided at that point, * make it the final one one. */ - if (read_sched_clock == jiffy_sched_clock_read) + if ((read_sched_clock == jiffy_sched_clock_read) && + (sched_clock_func == sched_clock_32)) setup_sched_clock(jiffy_sched_clock_read, 32, HZ); sched_clock_poll(sched_clock_timer.data); -- 1.7.9.5
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