MIPS, Perf-events: Work with irq_work

This is the MIPS part of the following commit by Peter Zijlstra:

- e360adbe29241a0194e10e20595360dd7b98a2b3
    irq_work: Add generic hardirq context callbacks

    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.

For MIPSXX, we need to call irq_work_run() at the tail of the perf IRQ
handler as described above.

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com,
Patchwork: http://patchwork.linux-mips.org/patch/2011/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 972695e359ebb2eee64f234251fd0833daacffb6..bd7b64d252dc7772743992e33531bd7f8da5f67f 100644 (file)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -4,6 +4,7 @@ config MIPS
        select HAVE_GENERIC_DMA_COHERENT
        select HAVE_IDE
        select HAVE_OPROFILE
        select HAVE_GENERIC_DMA_COHERENT
        select HAVE_IDE
        select HAVE_OPROFILE

+       select HAVE_IRQ_WORK

        select HAVE_PERF_EVENTS
        select PERF_USE_VMALLOC
        select HAVE_ARCH_KGDB
        select HAVE_PERF_EVENTS
        select PERF_USE_VMALLOC
        select HAVE_ARCH_KGDB

diff --git a/arch/mips/include/asm/perf_event.h b/arch/mips/include/asm/perf_event.h
index e00007cf816220ed3f62c9269372d1f050714027..d0c77496c7281fdca202a46ef8d453aa04557f7b 100644 (file)
--- a/arch/mips/include/asm/perf_event.h
+++ b/arch/mips/include/asm/perf_event.h
@@ -11,15 +11,5 @@
 
 #ifndef __MIPS_PERF_EVENT_H__
 #define __MIPS_PERF_EVENT_H__
 
 #ifndef __MIPS_PERF_EVENT_H__
 #define __MIPS_PERF_EVENT_H__

-
-/*
- * MIPS performance counters do not raise NMI upon overflow, a regular
- * interrupt will be signaled. Hence we can do the pending perf event
- * work at the tail of the irq handler.
- */
-static inline void
-set_perf_event_pending(void)
-{
-}
-
+/* Leave it empty here. The file is required by linux/perf_event.h */

 #endif /* __MIPS_PERF_EVENT_H__ */
 #endif /* __MIPS_PERF_EVENT_H__ */

diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 183e0d226669193700c72f405f1e4e43303612a4..d45ea37062bc5377a4624b35f95923d4f311f23f 100644 (file)
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -696,7 +696,7 @@ static int mipsxx_pmu_handle_shared_irq(void)
         * interrupt, not NMI.
         */
        if (handled == IRQ_HANDLED)
         * interrupt, not NMI.
         */
        if (handled == IRQ_HANDLED)

-               perf_event_do_pending();
+               irq_work_run();

 
 #ifdef CONFIG_MIPS_MT_SMP
        read_unlock(&pmuint_rwlock);
 
 #ifdef CONFIG_MIPS_MT_SMP
        read_unlock(&pmuint_rwlock);