>> Scope-based resource management became supported for some
>> programming interfaces by contributions of Peter Zijlstra on 2023-05-26.
>> See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:
>> Introduce __cleanup() based infrastructure").
>>
>> * Thus replace local_irq_save() and local_irq_restore() calls by calls
>> of the macro “guard(irqsave)”.
…
>> ---
>> arch/powerpc/perf/core-book3s.c | 102 +++++++++++++-------------------
>> 1 file changed, 42 insertions(+), 60 deletions(-)
>
> These mostly look good.
Thanks for this positive feedback.
> I don't think the change to power_pmu_event_init() is an improvement.
I presented an other development opinion.
> I'll drop that hunk when applying,
I guess that there are further opportunities to clarify remaining change resistance.
> or you can send a v2 without that change if you prefer.
Not yet.
…
>> @@ -1996,7 +1980,7 @@ static bool is_event_blacklisted(u64 ev)
>> static int power_pmu_event_init(struct perf_event *event)
>> {
>> u64 ev;
>> - unsigned long flags, irq_flags;
>> + unsigned long flags;
>> struct perf_event *ctrs[MAX_HWEVENTS];
>> u64 events[MAX_HWEVENTS];
>> unsigned int cflags[MAX_HWEVENTS];
>> @@ -2115,43 +2099,41 @@ static int power_pmu_event_init(struct perf_event *event)
>> if (check_excludes(ctrs, cflags, n, 1))
>> return -EINVAL;
>>
>> - local_irq_save(irq_flags);
>> - cpuhw = this_cpu_ptr(&cpu_hw_events);
>> + {
>> + guard(irqsave)();
>> + cpuhw = this_cpu_ptr(&cpu_hw_events);
>>
>> - err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
>> + err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
>>
>> - if (has_branch_stack(event)) {
>> - u64 bhrb_filter = -1;
>> + if (has_branch_stack(event)) {
>> + u64 bhrb_filter = -1;
>>
>> - /*
>> - * Currently no PMU supports having multiple branch filters
>> - * at the same time. Branch filters are set via MMCRA IFM[32:33]
>> - * bits for Power8 and above. Return EOPNOTSUPP when multiple
>> - * branch filters are requested in the event attr.
>> - *
>> - * When opening event via perf_event_open(), branch_sample_type
>> - * gets adjusted in perf_copy_attr(). Kernel will automatically
>> - * adjust the branch_sample_type based on the event modifier
>> - * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
>> - * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
>> - */
>> - if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL) > 1) {
>> - local_irq_restore(irq_flags);
>> - return -EOPNOTSUPP;
>> - }
>> + /*
>> + * Currently no PMU supports having multiple branch filters
>> + * at the same time. Branch filters are set via MMCRA IFM[32:33]
>> + * bits for Power8 and above. Return EOPNOTSUPP when multiple
>> + * branch filters are requested in the event attr.
>> + *
>> + * When opening event via perf_event_open(), branch_sample_type
>> + * gets adjusted in perf_copy_attr(). Kernel will automatically
>> + * adjust the branch_sample_type based on the event modifier
>> + * settings to include PERF_SAMPLE_BRANCH_PLM_ALL. Hence drop
>> + * the check for PERF_SAMPLE_BRANCH_PLM_ALL.
>> + */
>> + if (hweight64(event->attr.branch_sample_type & ~PERF_SAMPLE_BRANCH_PLM_ALL)
>> + > 1)
>> + return -EOPNOTSUPP;
>>
>> - if (ppmu->bhrb_filter_map)
>> - bhrb_filter = ppmu->bhrb_filter_map(
>> - event->attr.branch_sample_type);
>> + if (ppmu->bhrb_filter_map)
>> + bhrb_filter = ppmu->bhrb_filter_map(event->attr.branch_sample_type);
>>
>> - if (bhrb_filter == -1) {
>> - local_irq_restore(irq_flags);
>> - return -EOPNOTSUPP;
>> + if (bhrb_filter == -1)
>> + return -EOPNOTSUPP;
>> +
>> + cpuhw->bhrb_filter = bhrb_filter;
>> }
>> - cpuhw->bhrb_filter = bhrb_filter;
>> }
>>
>> - local_irq_restore(irq_flags);
>> if (err)
>> return -EINVAL;
>>
>> --
>> 2.46.0
* Under which circumstances would you find it acceptable to use
the proposed compound statement?
* Would you eventually prefer to apply a macro like “scoped_guard” here?
https://elixir.bootlin.com/linux/v6.11/source/include/linux/cleanup.h#L140
Regards,
Markus
