kernel/include/asm-generic/cputime_nsecs.h, branch linux-4.15.y

ia64, sched/cputime: Move the nsecs based cputime headers to the last arch using it

2017-02-01T08:14:01Z

Initially, nsec based cputime_t implementation belonged to IA64. It got exported later for CONFIG_VIRT_CPU_ACCOUNTING_GEN but now it is again only used by IA64. So let's move it back there. Signed-off-by: Frederic Weisbecker Cc: Benjamin Herrenschmidt Cc: Fenghua Yu Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Rik van Riel Cc: Stanislaw Gruszka Cc: Thomas Gleixner Cc: Tony Luck Cc: Wanpeng Li Link: http://lkml.kernel.org/r/1485832191-26889-29-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar

sched/cputime, powerpc: Remove cputime_to_scaled()

2016-11-15T08:51:04Z

Currently cputime_to_scaled() just return it's argument on all implementations, we don't need to call this function. Signed-off-by: Stanislaw Gruszka Signed-off-by: Frederic Weisbecker Reviewed-by: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Neuling Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1479175612-14718-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar

sched/cputime: Count actually elapsed irq & softirq time

2016-07-14T08:42:34Z

Currently, if there was any irq or softirq time during 'ticks' jiffies, the entire period will be accounted as irq or softirq time. This is inaccurate if only a subset of the time was actually spent handling irqs, and could conceivably mis-count all of the ticks during a period as irq time, when there was some irq and some softirq time. This can actually happen when irqtime_account_process_tick is called from account_idle_ticks, which can pass a larger number of ticks down all at once. Fix this by changing irqtime_account_hi_update(), irqtime_account_si_update(), and steal_account_process_ticks() to work with cputime_t time units, and return the amount of time spent in each mode. Rename steal_account_process_ticks() to steal_account_process_time(), to reflect that time is now accounted in cputime_t, instead of ticks. Additionally, have irqtime_account_process_tick() take into account how much time was spent in each of steal, irq, and softirq time. The latter could help improve the accuracy of cputime accounting when returning from idle on a NO_HZ_IDLE CPU. Properly accounting how much time was spent in hardirq and softirq time will also allow the NO_HZ_FULL code to re-use these same functions for hardirq and softirq accounting. Signed-off-by: Rik van Riel [ Make nsecs_to_cputime64() actually return cputime64_t. ] Signed-off-by: Frederic Weisbecker Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krcmar Cc: Thomas Gleixner Cc: Wanpeng Li Link: http://lkml.kernel.org/r/1468421405-20056-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar

cputime: Prevent 32bit overflow in time[val|spec]_to_cputime()

2016-02-02T14:24:38Z

The datatype __kernel_time_t is u32 on 32bit platform, so its subject to overflows in the timeval/timespec to cputime conversion. Currently the following functions are affected: 1. setitimer() 2. timer_create/timer_settime() 3. sys_clock_nanosleep This can happen on MIPS32 and ARM32 with "Full dynticks CPU time accounting" enabled, which is required for CONFIG_NO_HZ_FULL. Enforce u64 conversion to prevent the overflow. Fixes: 31c1fc818715 ("ARM: Kconfig: allow full nohz CPU accounting") Signed-off-by: zengtao Reviewed-by: Arnd Bergmann Cc: Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1454384314-154784-1-git-send-email-prime.zeng@huawei.com Signed-off-by: Thomas Gleixner

sched, time: Fix build error with 64 bit cputime_t on 32 bit systems

2014-10-03T03:46:55Z

On 32 bit systems cmpxchg cannot handle 64 bit values, so some additional magic is required to allow a 32 bit system with CONFIG_VIRT_CPU_ACCOUNTING_GEN=y enabled to build. Make sure the correct cmpxchg function is used when doing an atomic swap of a cputime_t. Reported-by: Arnd Bergmann Signed-off-by: Rik van Riel Acked-by: Arnd Bergmann Signed-off-by: Peter Zijlstra (Intel) Cc: umgwanakikbuti@gmail.com Cc: fweisbec@gmail.com Cc: srao@redhat.com Cc: lwoodman@redhat.com Cc: atheurer@redhat.com Cc: oleg@redhat.com Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: linux390@de.ibm.com Cc: linux-arch@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Link: http://lkml.kernel.org/r/20140930155947.070cdb1f@annuminas.surriel.com Signed-off-by: Ingo Molnar

cputime: Bring cputime -> nsecs conversion

2014-03-13T14:56:44Z

We already have nsecs_to_cputime(). Now we need to be able to convert the other way around in order to fix a bug on steal time accounting. Cc: Ingo Molnar Cc: Marcelo Tosatti Cc: Peter Zijlstra Cc: Thomas Gleixner Acked-by: Rik van Riel Signed-off-by: Frederic Weisbecker

cputime: Fix nsecs_to_cputime() return type cast

2014-03-13T14:56:43Z

Even though nsec based cputime_t maps to u64, nsecs_to_cputime() must return a cputime_t value. We want to enforce this kind of cast in order to track down buggy manipulations of cputime_t such as direct access of its values under wrong assumptions on its backend type (nsecs, jiffies, etc...) by core code. Cc: Ingo Molnar Cc: Marcelo Tosatti Cc: Peter Zijlstra Cc: Thomas Gleixner Acked-by: Rik van Riel Signed-off-by: Frederic Weisbecker

cputime_nsecs: use math64.h for nsec resolution conversion helpers

2013-04-26T16:58:12Z

For the nsec resolution conversions to be useable on non 64-bit architectures, the helpers in need to be used so the right arch-specific 64-bit math helpers can be used (e.g. do_div()) Signed-off-by: Kevin Hilman Cc: Christoph Lameter Cc: Hakan Akkan Cc: Ingo Molnar Cc: Kevin Hilman Cc: Li Zhong Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Signed-off-by: Frederic Weisbecker

cputime: Constify timeval_to_cputime(timeval) argument

2013-02-24T11:57:15Z

Saw the following compiler warning on the linux-next tree: kernel/itimer.c: In function 'set_cpu_itimer': kernel/itimer.c:152:2: warning: passing argument 1 of 'timeval_to_cputime' discards 'const' qualifier from pointer target type [enabled by default] ... timeval_to_cputime() is always passed a constant timeval in argument, we need to teach the nsecs based cputime implementation about that. Signed-off-by: Li Zhong Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Kevin Hilman Link: http://lkml.kernel.org/r/1361636925-22288-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar Cc: Steven Rostedt Cc: Kevin Hilman

cputime: Generic on-demand virtual cputime accounting

2013-01-27T18:23:27Z

If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Ingo Molnar Cc: Li Zhong Cc: Namhyung Kim Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner