[PATCH 0/4] cputime: some optimizations and cleanups

Stanislaw Gruszka
2016-10-31T12:36:25Z

Patches remove accounting of utimescaled/stimescaled on architectures
that do not provide those values (scaled cputimes are equal to normal
cputimes) what is every architecture except powerpc and s390.

Patches do not change user visible behaviour.

There is very little documentation how scaled cputimes should be
interpreted and what useful information they provide (at least
I could not find that). Moreover they are exported to user-space
only via not commonly used taskstats and delayacct interfaces (i.e.
interfaces that are not used by standard linux tools AFICT). However
I assume they can not be removed by whole (i.e. replaced by normal
utimes/stimes on powerpc and s390).

Stanislaw Gruszka (4):
cputime/powerpc: remove cputime_last_delta global variable
cputime/powerpc: remove cputime_to_scaled()
cputime/powerpc/s390: make scaled cputime arch specific
cputime: simplify task_cputime()

arch/ia64/kernel/time.c | 4 +-
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/cputime.h | 14 ----
arch/powerpc/kernel/time.c | 8 +-
arch/s390/Kconfig | 1 +
arch/s390/kernel/vtime.c | 9 ++-
arch/x86/kernel/apm_32.c | 4 +-
include/asm-generic/cputime_jiffies.h | 1 -
include/asm-generic/cputime_nsecs.h | 1 -
include/linux/kernel_stat.h | 4 +-
include/linux/sched.h | 29 +++++---
kernel/fork.c | 2 +
kernel/sched/cputime.c | 124 +++++++++------------------------
kernel/time/posix-cpu-timers.c | 4 +-
14 files changed, 73 insertions(+), 133 deletions(-)