mirror of
https://github.com/torvalds/linux.git
synced 2024-12-12 14:12:51 +00:00
powerpc: Tell RCU about idle after hcall tracing
The PowerPC pSeries platform (CONFIG_PPC_PSERIES=y) enables hypervisor-call tracing for CONFIG_TRACEPOINTS=y kernels. One of the hypervisor calls that is traced is the H_CEDE call in the idle loop that tells the hypervisor that this OS instance no longer needs the current CPU. However, tracing uses RCU, so this combination of kernel configuration variables needs to avoid telling RCU about the current CPU's idleness until after the H_CEDE-entry tracing completes on the one hand, and must tell RCU that the the current CPU is no longer idle before the H_CEDE-exit tracing starts. In all other cases, it suffices to inform RCU of CPU idleness upon idle-loop entry and exit. This commit makes the required adjustments. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
parent
416eb33cd6
commit
a7b152d534
@ -46,6 +46,12 @@ static int __init powersave_off(char *arg)
|
|||||||
}
|
}
|
||||||
__setup("powersave=off", powersave_off);
|
__setup("powersave=off", powersave_off);
|
||||||
|
|
||||||
|
#if defined(CONFIG_PPC_PSERIES) && defined(CONFIG_TRACEPOINTS)
|
||||||
|
static const bool idle_uses_rcu = 1;
|
||||||
|
#else
|
||||||
|
static const bool idle_uses_rcu;
|
||||||
|
#endif
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* The body of the idle task.
|
* The body of the idle task.
|
||||||
*/
|
*/
|
||||||
@ -56,6 +62,9 @@ void cpu_idle(void)
|
|||||||
|
|
||||||
set_thread_flag(TIF_POLLING_NRFLAG);
|
set_thread_flag(TIF_POLLING_NRFLAG);
|
||||||
while (1) {
|
while (1) {
|
||||||
|
if (idle_uses_rcu)
|
||||||
|
tick_nohz_idle_enter();
|
||||||
|
else
|
||||||
tick_nohz_idle_enter_norcu();
|
tick_nohz_idle_enter_norcu();
|
||||||
while (!need_resched() && !cpu_should_die()) {
|
while (!need_resched() && !cpu_should_die()) {
|
||||||
ppc64_runlatch_off();
|
ppc64_runlatch_off();
|
||||||
@ -93,6 +102,9 @@ void cpu_idle(void)
|
|||||||
|
|
||||||
HMT_medium();
|
HMT_medium();
|
||||||
ppc64_runlatch_on();
|
ppc64_runlatch_on();
|
||||||
|
if (idle_uses_rcu)
|
||||||
|
tick_nohz_idle_exit();
|
||||||
|
else
|
||||||
tick_nohz_idle_exit_norcu();
|
tick_nohz_idle_exit_norcu();
|
||||||
preempt_enable_no_resched();
|
preempt_enable_no_resched();
|
||||||
if (cpu_should_die())
|
if (cpu_should_die())
|
||||||
|
@ -555,6 +555,8 @@ void __trace_hcall_entry(unsigned long opcode, unsigned long *args)
|
|||||||
|
|
||||||
(*depth)++;
|
(*depth)++;
|
||||||
trace_hcall_entry(opcode, args);
|
trace_hcall_entry(opcode, args);
|
||||||
|
if (opcode == H_CEDE)
|
||||||
|
rcu_idle_enter();
|
||||||
(*depth)--;
|
(*depth)--;
|
||||||
|
|
||||||
out:
|
out:
|
||||||
@ -575,6 +577,8 @@ void __trace_hcall_exit(long opcode, unsigned long retval,
|
|||||||
goto out;
|
goto out;
|
||||||
|
|
||||||
(*depth)++;
|
(*depth)++;
|
||||||
|
if (opcode == H_CEDE)
|
||||||
|
rcu_idle_exit();
|
||||||
trace_hcall_exit(opcode, retval, retbuf);
|
trace_hcall_exit(opcode, retval, retbuf);
|
||||||
(*depth)--;
|
(*depth)--;
|
||||||
|
|
||||||
|
Loading…
Reference in New Issue
Block a user