Commit a8b0ca17 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf: Remove the nmi parameter from the swevent and overflow interface 



The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.

For the various event classes:

  - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
    the PMI-tail (ARM etc.)
  - tracepoint: nmi=0; since tracepoint could be from NMI context.
  - software: nmi=[0,1]; some, like the schedule thing cannot
    perform wakeups, and hence need 0.

As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).

The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1880c4ae

arch/alpha/kernel/perf_event.c

+1 −1
Original line number Diff line number Diff line
@@ -847,7 +847,7 @@ static void alpha_perf_event_irq_handler(unsigned long la_ptr, 
	data.period = event->hw.last_period;



	if (alpha_perf_event_set_period(event, hwc, idx)) {

		if (perf_event_overflow(event, 1, &data, regs)) {

		if (perf_event_overflow(event, &data, regs)) {

			/* Interrupts coming too quickly; "throttle" the

			 * counter, i.e., disable it for a little while.

			 */

arch/arm/kernel/perf_event_v6.c

+1 −1
Original line number Diff line number Diff line
@@ -479,7 +479,7 @@ armv6pmu_handle_irq(int irq_num, 
		if (!armpmu_event_set_period(event, hwc, idx))

			continue;



		if (perf_event_overflow(event, 0, &data, regs))

		if (perf_event_overflow(event, &data, regs))

			armpmu->disable(hwc, idx);

	}

arch/arm/kernel/perf_event_v7.c

+1 −1
Original line number Diff line number Diff line
@@ -787,7 +787,7 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev) 
		if (!armpmu_event_set_period(event, hwc, idx))

			continue;



		if (perf_event_overflow(event, 0, &data, regs))

		if (perf_event_overflow(event, &data, regs))

			armpmu->disable(hwc, idx);

	}

arch/arm/kernel/perf_event_xscale.c

+2 −2
Original line number Diff line number Diff line
@@ -251,7 +251,7 @@ xscale1pmu_handle_irq(int irq_num, void *dev) 
		if (!armpmu_event_set_period(event, hwc, idx))

			continue;



		if (perf_event_overflow(event, 0, &data, regs))

		if (perf_event_overflow(event, &data, regs))

			armpmu->disable(hwc, idx);

	}
@@ -583,7 +583,7 @@ xscale2pmu_handle_irq(int irq_num, void *dev) 
		if (!armpmu_event_set_period(event, hwc, idx))

			continue;



		if (perf_event_overflow(event, 0, &data, regs))

		if (perf_event_overflow(event, &data, regs))

			armpmu->disable(hwc, idx);

	}

arch/arm/kernel/ptrace.c

+1 −1
Original line number Diff line number Diff line
@@ -396,7 +396,7 @@ static long ptrace_hbp_idx_to_num(int idx) 
/*

 * Handle hitting a HW-breakpoint.

 */

static void ptrace_hbptriggered(struct perf_event *bp, int unused,

static void ptrace_hbptriggered(struct perf_event *bp,

				     struct perf_sample_data *data,

				     struct pt_regs *regs)

{

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