xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

irq_work: Add generic hardirq context callbacks

Browse Source 
Provide a mechanism that allows running code in IRQ context. It is
most useful for NMI code that needs to interact with the rest of the
system -- like wakeup a task to drain buffers.

Perf currently has such a mechanism, so extract that and provide it as
a generic feature, independent of perf so that others may also
benefit.

The IRQ context callback is generated through self-IPIs where
possible, or on architectures like powerpc the decrementer (the
built-in timer facility) is set to generate an interrupt immediately.

Architectures that don't have anything like this get to do with a
callback from the timer tick. These architectures can call
irq_work_run() at the tail of any IRQ handlers that might enqueue such
work (like the perf IRQ handler) to avoid undue latencies in
processing the work.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ various fixes ]
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
2010-10-14 14:01:34 +08:00
committed by Ingo Molnar
parent 8e5fc1a732
commit e360adbe29
39 changed files with 311 additions and 242 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
arch/powerpc/kernel/time.c
View File

@@ -53,7 +53,7 @@
#include <linux/posix-timers.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/perf_event.h>
#include <linux/irq_work.h>
#include <asm/trace.h>
#include <asm/io.h>
@@ -493,60 +493,60 @@ void __init iSeries_time_init_early(void)
}
#endif /* CONFIG_PPC_ISERIES */
#ifdef CONFIG_PERF_EVENTS
#ifdef CONFIG_IRQ_WORK
/*
* 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
*/
#ifdef CONFIG_PPC64
static inline unsigned long test_perf_event_pending(void)
static inline unsigned long test_irq_work_pending(void)
{
unsigned long x;
asm volatile("lbz %0,%1(13)"
: "=r" (x)
: "i" (offsetof(struct paca_struct, perf_event_pending)));
: "i" (offsetof(struct paca_struct, irq_work_pending)));
return x;
}
static inline void set_perf_event_pending_flag(void)
static inline void set_irq_work_pending_flag(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (1),
"i" (offsetof(struct paca_struct, perf_event_pending)));
"i" (offsetof(struct paca_struct, irq_work_pending)));
}
static inline void clear_perf_event_pending(void)
static inline void clear_irq_work_pending(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (0),
"i" (offsetof(struct paca_struct, perf_event_pending)));
"i" (offsetof(struct paca_struct, irq_work_pending)));
}
#else /* 32-bit */
DEFINE_PER_CPU(u8, perf_event_pending);
DEFINE_PER_CPU(u8, irq_work_pending);
#define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1
#define test_perf_event_pending() __get_cpu_var(perf_event_pending)
#define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0
#define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1
#define test_irq_work_pending() __get_cpu_var(irq_work_pending)
#define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0
#endif /* 32 vs 64 bit */
void set_perf_event_pending(void)
void set_irq_work_pending(void)
{
preempt_disable();
set_perf_event_pending_flag();
set_irq_work_pending_flag();
set_dec(1);
preempt_enable();
}
#else /* CONFIG_PERF_EVENTS */
#else /* CONFIG_IRQ_WORK */
#define test_perf_event_pending() 0
#define clear_perf_event_pending()
#define test_irq_work_pending() 0
#define clear_irq_work_pending()
#endif /* CONFIG_PERF_EVENTS */
#endif /* CONFIG_IRQ_WORK */
/*
* For iSeries shared processors, we have to let the hypervisor
@@ -587,9 +587,9 @@ void timer_interrupt(struct pt_regs * regs)
calculate_steal_time();
if (test_perf_event_pending()) {
clear_perf_event_pending();
perf_event_do_pending();
if (test_irq_work_pending()) {
clear_irq_work_pending();
irq_work_run();
}
#ifdef CONFIG_PPC_ISERIES