The functionality of context tracking has been implemented by PPC64 and HAVE_CONTEXT_TRACKING was selected by pseries by default. Actually, it is applicale to all PPC64 platforms, so select it in PPC64 generic Kconfig.
NO_HZ_FULL depends on it, with this change NO_HZ_FULL could be enabled for all PPC64 machines.
Signed-off-by: Yang Shi yang.shi@linaro.org --- Following the instruction in Documentation/timers/NO_HZ.txt, I tested full nohz on my FSL T2080 target, the below trace log shows it works well.
user_loop-574 [001] d..1 137.044892: tick_stop: success=yes msg= user_loop-574 [001] d.h1 138.044880: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=137796002092 user_loop-574 [001] d.h1 139.044880: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=138796002129 user_loop-574 [001] d.h1 140.044880: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=139796002219 user_loop-574 [001] d.h1 141.044880: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=140796002229 user_loop-574 [001] d.h1 142.044879: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=141796002159 user_loop-574 [001] d.h1 143.044879: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=142796002142 user_loop-574 [001] d.h1 144.044878: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=143796002046 user_loop-574 [001] d.h1 145.044878: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=144796002189 user_loop-574 [001] d.h1 146.044878: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=145796002199 user_loop-574 [001] d.h1 147.044880: hrtimer_expire_entry: hrtimer=c00000007fd22d10 function=.tick_sched_timer now=146796003836
It shows the timer tick just comes in every second.
It should be low risk to have problem on other PPC64 targets, although they are not tested.
arch/powerpc/platforms/Kconfig.cputype | 1 + arch/powerpc/platforms/pseries/Kconfig | 1 - 2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 142dff5..7b25dd1 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -3,6 +3,7 @@ config PPC64 default n select HAVE_VIRT_CPU_ACCOUNTING select ZLIB_DEFLATE + select HAVE_CONTEXT_TRACKING help This option selects whether a 32-bit or a 64-bit kernel will be built. diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index bec90fb..6853148 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -17,7 +17,6 @@ config PPC_PSERIES select PPC_UDBG_16550 select PPC_NATIVE select PPC_DOORBELL - select HAVE_CONTEXT_TRACKING select HOTPLUG_CPU if SMP select ARCH_RANDOM select PPC_DOORBELL