Messages in this thread | | | Subject | Re: [PATCH v2 1/6] perf: Add interface to add general events to sysfs | From | Lin Ming <> | Date | Mon, 25 Jul 2011 16:32:31 +0800 |
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On Mon, 2011-07-25 at 15:57 +0800, Peter Zijlstra wrote: > On Tue, 2011-07-19 at 15:52 +0800, Lin Ming wrote: > > > > I'd rather not have a function pointer here, and all the kobj thingies > > > can be hooking into the existing struct device, right? > > > > I forgot to mention one important reason why I added a function pointer. > > > > The events can only be added to sysfs after PMU sysfs is initialized in > > perf_event_sysfs_init -> > > pmu_dev_alloc > > Right. > > > > @@ -5571,6 +5571,8 @@ static int pmu_dev_alloc(struct pmu *pmu) > > > if (ret) > > > goto free_dev; > > > > > > + if (pmu->add_events) > > > + pmu->add_events(); > > > > So we need a pmu callback which is called in pmu_dev_alloc to add events > > to sysfs. > > > > You suggested a new interface, > > int perf_pmu_add_event(struct pmu *pmu, const char *name, u64 config) > > > > But where should it be called? > > I guess you mean to call it in pmu init function, for example, > > uncore_pmu_init. > > > > But pmu init function maybe called before perf_event_sysfs_init, which > > means the pmu sysfs has not been initialized yet. > > Right, so there is no reason to call perf_pmu_register() really early, > except for the normal pmu and the software pmu (since they're used by > the watchdog muck). > > The uncore for example can use late_initcall() just fine and use both > perf_pmu_register() and the proposed perf_pmu_add_event() from the same > init call. > > Only for the primary pmu and software thingies do we need to add an > extra init call.
This seems a solution.
I'll use late_initcall for uncore. Then later we can add an extra late_initcall for normal pmu and software pmu.
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