forked from luck/tmp_suning_uos_patched
8d495477d6
On context switch we are locking the vtime seqcount of the scheduling-out task twice: * On vtime_task_switch_common(), when we flush the pending vtime through vtime_account_system() * On arch_vtime_task_switch() to reset the vtime state. This is pointless as these actions can be performed without the need to unlock/lock in the middle. The reason these steps are separated is to consolidate a very small amount of common code between CONFIG_VIRT_CPU_ACCOUNTING_GEN and CONFIG_VIRT_CPU_ACCOUNTING_NATIVE. Performance in this fast path is definitely a priority over artificial code factorization so split the task switch code between GEN and NATIVE and mutualize the parts than can run under a single seqcount locked block. As a side effect, vtime_account_idle() becomes included in the seqcount protection. This happens to be a welcome preparation in order to properly support kcpustat under vtime in the future and fetch CPUTIME_IDLE without race. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Link: https://lkml.kernel.org/r/20191003161745.28464-3-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| autogroup.c | ||
| autogroup.h | ||
| clock.c | ||
| completion.c | ||
| core.c | ||
| cpuacct.c | ||
| cpudeadline.c | ||
| cpudeadline.h | ||
| cpufreq_schedutil.c | ||
| cpufreq.c | ||
| cpupri.c | ||
| cpupri.h | ||
| cputime.c | ||
| deadline.c | ||
| debug.c | ||
| fair.c | ||
| features.h | ||
| idle.c | ||
| isolation.c | ||
| loadavg.c | ||
| Makefile | ||
| membarrier.c | ||
| pelt.c | ||
| pelt.h | ||
| psi.c | ||
| rt.c | ||
| sched-pelt.h | ||
| sched.h | ||
| stats.c | ||
| stats.h | ||
| stop_task.c | ||
| swait.c | ||
| topology.c | ||
| wait_bit.c | ||
| wait.c | ||