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powerpc/opal: Wake up kopald polling thread before waiting for events

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On some environments (prototype machines, some simulators, etc...)
there is no functional interrupt source to signal completion, so
we rely on the fairly slow OPAL heartbeat.

In a number of cases, the calls complete very quickly or even
immediately. We've observed that it helps a lot to wakeup the OPAL
heartbeat thread before waiting for event in those cases, it will
call OPAL immediately to collect completions for anything that
finished fast enough.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-By: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Benjamin Herrenschmidt 2016-07-04 14:51:44 +10:00 committed by Michael Ellerman
parent 68a2d80c80
commit a203658b5e
3 changed files with 17 additions and 2 deletions
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2
arch/powerpc/include/asm/opal.h
View File

@ -292,6 +292,8 @@ static inline int opal_get_async_rc(struct opal_msg msg)
return be64_to_cpu(msg.params[1]);
}
void opal_wake_poller(void);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_OPAL_H */

5
arch/powerpc/platforms/powernv/opal-async.c
View File

@ -117,6 +117,11 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
return -EINVAL;
}
/* Wakeup the poller before we wait for events to speed things
* up on platforms or simulators where the interrupts aren't
* functional.
*/
opal_wake_poller();
wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
memcpy(msg, &opal_async_responses[token], sizeof(*msg));

12
arch/powerpc/platforms/powernv/opal.c
View File

@ -55,6 +55,7 @@ struct device_node *opal_node;
static DEFINE_SPINLOCK(opal_write_lock);
static struct atomic_notifier_head opal_msg_notifier_head[OPAL_MSG_TYPE_MAX];
static uint32_t opal_heartbeat;
static struct task_struct *kopald_tsk;
static void opal_reinit_cores(void)
{
@ -653,6 +654,7 @@ static void opal_i2c_create_devs(void)
static int kopald(void *unused)
{
unsigned long timeout = msecs_to_jiffies(opal_heartbeat) + 1;
__be64 events;
set_freezable();
@ -660,12 +662,18 @@ static int kopald(void *unused)
try_to_freeze();
opal_poll_events(&events);
opal_handle_events(be64_to_cpu(events));
msleep_interruptible(opal_heartbeat);
schedule_timeout_interruptible(timeout);
} while (!kthread_should_stop());
return 0;
}
void opal_wake_poller(void)
{
if (kopald_tsk)
wake_up_process(kopald_tsk);
}
static void opal_init_heartbeat(void)
{
/* Old firwmware, we assume the HVC heartbeat is sufficient */
@ -674,7 +682,7 @@ static void opal_init_heartbeat(void)
opal_heartbeat = 0;
if (opal_heartbeat)
kthread_run(kopald, NULL, "kopald");
kopald_tsk = kthread_run(kopald, NULL, "kopald");
}
static int __init opal_init(void)