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perf_counter: abstract wakeup flag setting in core to fix powerpc build

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Impact: build fix for powerpc

Commit bd753921015e7905 ("perf_counter: software counter event
infrastructure") introduced a use of TIF_PERF_COUNTERS into the core
perfcounter code.  This breaks the build on powerpc because we use
a flag in a per-cpu area to signal wakeups on powerpc rather than
a thread_info flag, because the thread_info flags have to be
manipulated with atomic operations and are thus slower than per-cpu
flags.

This fixes the by changing the core to use an abstracted
set_perf_counter_pending() function, which is defined on x86 to set
the TIF_PERF_COUNTERS flag and on powerpc to set the per-cpu flag
(paca->perf_counter_pending).  It changes the previous powerpc
definition of set_perf_counter_pending to not take an argument and
adds a clear_perf_counter_pending, so as to simplify the definition
on x86.

On x86, set_perf_counter_pending() is defined as a macro.  Defining
it as a static inline in arch/x86/include/asm/perf_counters.h causes
compile failures because <asm/perf_counters.h> gets included early in
<linux/sched.h>, and the definitions of set_tsk_thread_flag etc. are
therefore not available in <asm/perf_counters.h>.  (On powerpc this
problem is avoided by defining set_perf_counter_pending etc. in
<asm/hw_irq.h>.)

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras
2009-03-16 21:00:00 +11:00
committed by Ingo Molnar
parent 7bb497bd88
commit b6c5a71da1
5 changed files with 19 additions and 14 deletions
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11
arch/powerpc/kernel/irq.c
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@@ -104,13 +104,6 @@ static inline notrace void set_soft_enabled(unsigned long enable)
: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}
#ifdef CONFIG_PERF_COUNTERS
notrace void __weak perf_counter_do_pending(void)
{
set_perf_counter_pending(0);
}
#endif
notrace void raw_local_irq_restore(unsigned long en)
{
/*
@@ -142,8 +135,10 @@ notrace void raw_local_irq_restore(unsigned long en)
iseries_handle_interrupts();
}
if (get_perf_counter_pending())
if (get_perf_counter_pending()) {
clear_perf_counter_pending();
perf_counter_do_pending();
}
/*
* if (get_paca()->hard_enabled) return;