Joel Stanley <j...@jms.id.au> writes: > It's not done anything for a long time. Save the percpu variable, and > emit a warning to remind users to not expect it to do anything. > > Fixes: 3fa8cad82b94 ("powerpc/pseries/cpuidle: smt-snooze-delay cleanup.") > Cc: sta...@vger.kernel.org # v3.14 > Signed-off-by: Joel Stanley <j...@jms.id.au> > -- > v2: > Use pr_warn instead of WARN > Reword and print proccess name with pid in message > Leave CPU_FTR_SMT test in > Add Fixes line > > mpe, if you don't agree then feel free to drop the cc stable. > > Testing 'ppc64_cpu --smt=off' on a 24 core / 4 SMT system it's quite noisy > as the online/offline loop that ppc64_cpu runs is slow.
Hmm, that is pretty spammy. I know I suggested the ratelimit, but I was thinking it would print once for each ppc64_cpu invocation, not ~30 times. How about pr_warn_once(), that should still be sufficient for people to notice if they're looking for it. ... > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c > index 571b3259697e..ba6d4cee19ef 100644 > --- a/arch/powerpc/kernel/sysfs.c > +++ b/arch/powerpc/kernel/sysfs.c > @@ -32,29 +32,26 @@ > > static DEFINE_PER_CPU(struct cpu, cpu_devices); > > -/* > - * SMT snooze delay stuff, 64-bit only for now > - */ > - > #ifdef CONFIG_PPC64 > > -/* Time in microseconds we delay before sleeping in the idle loop */ > -static DEFINE_PER_CPU(long, smt_snooze_delay) = { 100 }; > +/* > + * Snooze delay has not been hooked up since 3fa8cad82b94 > ("powerpc/pseries/cpuidle: > + * smt-snooze-delay cleanup.") and has been broken even longer. As was > foretold in > + * 2014: > + * > + * "ppc64_util currently utilises it. Once we fix ppc64_util, propose to > clean > + * up the kernel code." > + * > + * At some point in the future this code should be removed. > + */ > > static ssize_t store_smt_snooze_delay(struct device *dev, > struct device_attribute *attr, > const char *buf, > size_t count) > { > - struct cpu *cpu = container_of(dev, struct cpu, dev); > - ssize_t ret; > - long snooze; > - > - ret = sscanf(buf, "%ld", &snooze); > - if (ret != 1) > - return -EINVAL; > - > - per_cpu(smt_snooze_delay, cpu->dev.id) = snooze; > + pr_warn_ratelimited("%s (%d) used unsupported smt_snooze_delay, this > has no effect\n", > + current->comm, current->pid); Can we make this: "%s (%d) stored to unsupported smt_snooze_delay, which has no effect.\n", > return count; > } > > @@ -62,9 +59,9 @@ static ssize_t show_smt_snooze_delay(struct device *dev, > struct device_attribute *attr, > char *buf) > { > - struct cpu *cpu = container_of(dev, struct cpu, dev); > - > - return sprintf(buf, "%ld\n", per_cpu(smt_snooze_delay, cpu->dev.id)); > + pr_warn_ratelimited("%s (%d) used unsupported smt_snooze_delay, this > has no effect\n", > + current->comm, current->pid); It has as much effect as it ever did :) So maybe: "%s (%d) read from unsupported smt_snooze_delay.\n", I can do those changes when applying if you like rather than making you do a v3. cheers