ARM: perf: reword comments relating to perf_event_do_pending
Subsystems (3)
PATCH 1/1 ARM: perf: reword comments relating to perf_event_do_pending
This is purely a cosmetic change to the ARM perf backend because the current comments about the relationship between NMIs, interrupt context and perf_event_do_pending are misleading.
This patch updates the comments so that they reflect what the code actually does (which is in line with other architectures).
--- arch/arm/include/asm/perf_event.h | 2 +- arch/arm/kernel/perf_event.c | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-)
arch/arm/include/asm/perf_event.h +1 -1
@@ -17,7 +17,7 @@* counter interrupts are regular interrupts and not an NMI. This * means that when we receive the interrupt we can call * perf_event_do_pending() that handles all of the work with -* interrupts enabled. +* interrupts disabled. */ static inline void set_perf_event_pending (void )
arch/arm/kernel/perf_event.c +4 -4
@@ -1041,8 +1041,8 @@ armv6pmu_handle_irq(int irq_num,/* * Handle the pending perf events. * -* Note: this call *must* be run with interrupts enabled. For -* platforms that can have the PMU interrupts raised as a PMI, this +* Note: this call *must* be run with interrupts disabled. For +* platforms that can have the PMU interrupts raised as an NMI, this * will not work. */ perf_event_do_pending ();
@@ -2017,8 +2017,8 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev)/* * Handle the pending perf events. * -* Note: this call *must* be run with interrupts enabled. For -* platforms that can have the PMU interrupts raised as a PMI, this +* Note: this call *must* be run with interrupts disabled. For +* platforms that can have the PMU interrupts raised as an NMI, this * will not work. */ perf_event_do_pending ();
Signature · 1 line
1.6.3.3
PATCH 1/1 ARM: perf: reword comments relating to perf_event_do_pending
Quoted 9 lines · Will Deacon
This is purely a cosmetic change to the ARM perf backend because the current comments about the relationship between NMIs, interrupt context and
perf_event_do_pendingare misleading.This patch updates the comments so that they reflect what the code actually does (which is in line with other architectures).
Cc Jamie Iles <[email protected]>Signed-off-by Will Deacon <[email protected]>
Yep, that makes much more sense!
Jamie
PATCH 1/1 ARM: perf: reword comments relating to perf_event_do_pending
Hi Jamie,
Quoted 5 lines · Will Deacon
Quoted 4 lines
This is purely a cosmetic change to the ARM perf backend because the current comments about the relationship between NMIs, interrupt context and
perf_event_do_pendingare misleading.
Quoted 8 lines
Quoted 5 lines
This patch updates the comments so that they reflect what the code actually does (which is in line with other architectures).
Cc Jamie Iles <[email protected]>Signed-off-by Will Deacon <[email protected]>Yep, that makes much more sense!
Acked-by Jamie Iles <[email protected]>
Thanks for that. We could go a step further and remove the call to perf_event_do_pending entirely because we don't have NMI and therefore never queue up any pending events. I guess the caveat here is that we might hit subtle bugs in the future if pending events are used for things other than NMI (or if somebody crazy decides to use FIQ as a PMU interrupt).
I'll leave it in for the moment and submit this patch to the system.
Cheers,
Will