[PATCH V2] arm64: psci: Reduce waiting time of cpu_psci_cpu_kill()

Yunfeng Ye
2019-09-21T11:21:35Z

If psci_ops.affinity_info() fails, it will sleep 10ms, which will not
take so long in the right case. Use usleep_range() instead of msleep(),
reduce the waiting time, and give a chance to busy wait before sleep.

Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
---
V1->V2:
- use usleep_range() instead of udelay() after waiting for a while

arch/arm64/kernel/psci.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index c9f72b2..99b3122 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -82,6 +82,7 @@ static void cpu_psci_cpu_die(unsigned int cpu)
static int cpu_psci_cpu_kill(unsigned int cpu)
{
int err, i;
+ unsigned long timeout;

if (!psci_ops.affinity_info)
return 0;
@@ -91,16 +92,24 @@ static int cpu_psci_cpu_kill(unsigned int cpu)
* while it is dying. So, try again a few times.
*/

- for (i = 0; i < 10; i++) {
+ i = 0;
+ timeout = jiffies + msecs_to_jiffies(100);
+ do {
err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
pr_info("CPU%d killed.\n", cpu);
return 0;
}

- msleep(10);
- pr_info("Retrying again to check for CPU kill\n");
- }
+ /* busy-wait max 1ms */
+ if (i++ < 100) {
+ cond_resched();
+ udelay(10);
+ continue;
+ }
+
+ usleep_range(100, 1000);
+ } while (time_before(jiffies, timeout));

pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
cpu, err);
--
2.7.4.huawei.3