Messages in this thread | | | Date | Tue, 11 May 2010 01:09:13 +0200 | From | Frederic Weisbecker <> | Subject | Re: [RFC][PATCH 2/9] perf: core, remove hw_perf_event_init |
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On Mon, May 10, 2010 at 02:54:14PM +0200, Peter Zijlstra wrote: > On Mon, 2010-05-10 at 14:27 +0200, Frederic Weisbecker wrote: > > On Mon, May 10, 2010 at 12:19:29PM +0200, Peter Zijlstra wrote: > > > On Mon, 2010-05-10 at 18:17 +0800, Lin Ming wrote: > > > > On Mon, 2010-05-10 at 17:40 +0800, Peter Zijlstra wrote: > > > > > On Mon, 2010-05-10 at 17:26 +0800, Lin Ming wrote: > > > > > > +static struct pmu *perf_event_lookup_pmu(struct perf_event *event) > > > > > > +{ > > > > > > + struct pmu *pmu; > > > > > > + int pmu_id = event->attr.pmu_id; > > > > > > + > > > > > > + list_for_each_entry(pmu, &pmus, entry) { > > > > > > + if (pmu->id == pmu_id) > > > > > > + return pmu; > > > > > > + } > > > > > > + > > > > > > + return NULL; > > > > > > +} > > > > > > > > > > > +void perf_event_register_pmu(struct pmu *pmu) > > > > > > +{ > > > > > > + pmu->id = pmu_id_curr++; > > > > > > + list_add_tail(&pmu->entry, &pmus); > > > > > > +} > > > > > > > > > > That will be wanting some sort of synchronization > > > > > > > > Will add a mutex to protect the list of pmus. > > > > > > I'm thinking RCU might be better suited, a mutex for lookup doesn't > > > sound ideal. > > > > > > Is it really needed? I expect this function to be called on boot > > only. > > > > In fact I would even suggest to tag it as __init. > > Loadable modules as well as PCI-Hotplug need supporting.
Which module do you have in mind that could register a pmu? And I don't understand the problem with pci-hotplug.
Thanks.
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