On Fri, Oct 18, 2019 at 07:24:14PM +0800, Yunfeng Ye wrote: > In a case like suspend-to-disk, a large number of CPU cores need to be
Add suspend-to-ram also to list, i.e. "In case like suspend-to-disk and suspend-to-ram, a large number..." > shut down. At present, the CPU hotplug operation is serialised, and the > CPU cores can only be shut down one by one. In this process, if PSCI > affinity_info() does not return LEVEL_OFF quickly, cpu_psci_cpu_kill() > needs to wait for 10ms. If hundreds of CPU cores need to be shut down, > it will take a long time. > > Normally, it is no need to wait 10ms in cpu_psci_cpu_kill(). So change s/it is/there is/ > the wait interval from 10 ms to max 1 ms and use usleep_range() instead > of msleep() for more accurate schedule. > s/for more accurate schedule/for more accurate timer/ > In addition, reduce the time interval will increase the messages output, s/reduce/reducing/ > so remove the "Retry ..." message, instead, put the number of waiting > times to the sucessful message. > > Signed-off-by: Yunfeng Ye <[email protected]> > --- > v2 -> v3: > - update the comment > - remove the busy-wait logic, modify the loop logic and output message > > v1 -> v2: > - use usleep_range() instead of udelay() after waiting for a while > > arch/arm64/kernel/psci.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c > index c9f72b2665f1..00b8c0825a08 100644 > --- a/arch/arm64/kernel/psci.c > +++ b/arch/arm64/kernel/psci.c > @@ -91,15 +91,14 @@ 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++) { > + for (i = 0; i < 100; i++) { > 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); > + pr_info("CPU%d killed by waiting %d loops.\n", cpu, i); > return 0; > } > > - msleep(10); > - pr_info("Retrying again to check for CPU kill\n"); > + usleep_range(100, 1000); Since usleep_range can return anytime between 100us to 1ms, does it make sense to check for (time_before(jiffies, timeout)) you had in v2 ? -- Regards, Sudeep
