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Date: Tue, 29 Jun 2010 16:59:51 +0200 From: Peter Zijlstra <peterz@...radead.org> To: Frederic Weisbecker <fweisbec@...il.com> Cc: paulus <paulus@...ba.org>, stephane eranian <eranian@...glemail.com>, Robert Richter <robert.richter@....com>, Will Deacon <will.deacon@....com>, Paul Mundt <lethal@...ux-sh.org>, Cyrill Gorcunov <gorcunov@...il.com>, Lin Ming <ming.m.lin@...el.com>, Yanmin <yanmin_zhang@...ux.intel.com>, Deng-Cheng Zhu <dengcheng.zhu@...il.com>, David Miller <davem@...emloft.net>, linux-kernel@...r.kernel.org Subject: Re: [RFC][PATCH 09/11] perf: Default PMU ops On Tue, 2010-06-29 at 16:58 +0200, Frederic Weisbecker wrote: > On Thu, Jun 24, 2010 at 04:28:13PM +0200, Peter Zijlstra wrote: > > Provide default implementations for the pmu txn methods, this allows > > us to remove some conditional code. > > > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl> > > --- > > kernel/perf_event.c | 48 ++++++++++++++++++++++++++++++++++++------------ > > 1 file changed, 36 insertions(+), 12 deletions(-) > > > > Index: linux-2.6/kernel/perf_event.c > > =================================================================== > > --- linux-2.6.orig/kernel/perf_event.c > > +++ linux-2.6/kernel/perf_event.c > > @@ -656,21 +656,14 @@ group_sched_in(struct perf_event *group_ > > { > > struct perf_event *event, *partial_group = NULL; > > struct pmu *pmu = group_event->pmu; > > - bool txn = false; > > > > if (group_event->state == PERF_EVENT_STATE_OFF) > > return 0; > > > > - /* Check if group transaction availabe */ > > - if (pmu->start_txn) > > - txn = true; > > - > > - if (txn) > > - pmu->start_txn(pmu); > > + pmu->start_txn(pmu); > > > > if (event_sched_in(group_event, cpuctx, ctx)) { > > - if (txn) > > - pmu->cancel_txn(pmu); > > + pmu->cancel_txn(pmu); > > return -EAGAIN; > > } > > > > @@ -684,7 +677,7 @@ group_sched_in(struct perf_event *group_ > > } > > } > > > > - if (!txn || !pmu->commit_txn(pmu)) > > + if (!pmu->commit_txn(pmu)) > > return 0; > > > > group_error: > > @@ -699,8 +692,7 @@ group_error: > > } > > event_sched_out(group_event, cpuctx, ctx); > > > > - if (txn) > > - pmu->cancel_txn(pmu); > > + pmu->cancel_txn(pmu); > > > > return -EAGAIN; > > } > > @@ -4755,6 +4747,26 @@ static struct list_head pmus; > > static DEFINE_MUTEX(pmus_lock); > > static struct srcu_struct pmus_srcu; > > > > +static void perf_pmu_nop(struct pmu *pmu) > > +{ > > +} > > + > > +static void perf_pmu_start_txn(struct pmu *pmu) > > +{ > > + perf_pmu_disable(pmu); > > +} > > + > > +static int perf_pmu_commit_txn(struct pmu *pmu) > > +{ > > + perf_pmu_enable(pmu); > > + return 0; > > +} > > + > > +static void perf_pmu_cancel_txn(struct pmu *pmu) > > +{ > > + perf_pmu_enable(pmu); > > +} > > > So why do you need perf_pmu_*able wrappers now that you brings stubs > if none is provided? > > Actually, one problem is that it makes calling two indirect nops > for software events. > > Should the txn things really map to the enable/disable ops is the > off-case? Probably better let pmu implementations deal with that. > If they didn't provide txn implementations, it means they don't need it, > hence it should directly map to a nop. > You mean, if (!pmu->start_txn && pmu->pmu_enable) { /* install defaults */ } ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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