From: Johannes Weiner <[email protected]> Move the unlikely branches out of line. This eliminates undesirable jumps during wakeup and sleeps for workloads that aren't under any sort of resource pressure.
Signed-off-by: Johannes Weiner <[email protected]> --- kernel/sched/psi.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 0fe6ff6a6a15..3907a6b847aa 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -219,17 +219,17 @@ static bool test_state(unsigned int *tasks, enum psi_states state) { switch (state) { case PSI_IO_SOME: - return tasks[NR_IOWAIT]; + return unlikely(tasks[NR_IOWAIT]); case PSI_IO_FULL: - return tasks[NR_IOWAIT] && !tasks[NR_RUNNING]; + return unlikely(tasks[NR_IOWAIT] && !tasks[NR_RUNNING]); case PSI_MEM_SOME: - return tasks[NR_MEMSTALL]; + return unlikely(tasks[NR_MEMSTALL]); case PSI_MEM_FULL: - return tasks[NR_MEMSTALL] && !tasks[NR_RUNNING]; + return unlikely(tasks[NR_MEMSTALL] && !tasks[NR_RUNNING]); case PSI_CPU_SOME: - return tasks[NR_RUNNING] > tasks[NR_ONCPU]; + return unlikely(tasks[NR_RUNNING] > tasks[NR_ONCPU]); case PSI_CPU_FULL: - return tasks[NR_RUNNING] && !tasks[NR_ONCPU]; + return unlikely(tasks[NR_RUNNING] && !tasks[NR_ONCPU]); case PSI_NONIDLE: return tasks[NR_IOWAIT] || tasks[NR_MEMSTALL] || tasks[NR_RUNNING]; @@ -729,7 +729,7 @@ static void psi_group_change(struct psi_group *group, int cpu, * task in a cgroup is in_memstall, the corresponding groupc * on that cpu is in PSI_MEM_FULL state. */ - if (groupc->tasks[NR_ONCPU] && cpu_curr(cpu)->in_memstall) + if (unlikely(groupc->tasks[NR_ONCPU] && cpu_curr(cpu)->in_memstall)) state_mask |= (1 << PSI_MEM_FULL); groupc->state_mask = state_mask; -- 2.11.0
