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psi: Pressure states are unlikely

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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]>
Signed-off-by: Chengming Zhou <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
This commit is contained in:
Johannes Weiner authored and Ingo Molnar committed 2021-03-06 12:40:23 +01:00
1 parent 7fae6c8171
commit fddc8bab53
1 file changed
+7 -7
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kernel/sched/psi.c
+7 -7
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@@ -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;