time: Optimize ns_to_timespec64()

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ns_to_timespec64() calls div_s64_rem(), which is a rather slow function on
32-bit architectures, as it cannot take advantage of the do_div()
optimizations for constant arguments.

Open-code the div_s64_rem() function in ns_to_timespec64(), so a constant
divider can be passed into the optimized div_u64_rem() function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191108203435.112759-3-arnd@arndb.de

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Arnd Bergmann 2019-11-08 21:34:25 +01:00 • committed by Thomas Gleixner

parent 56144737e6

commit 20d087368d

1 changed files with 12 additions and 9 deletions

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kernel/time/time.c

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