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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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14
arch/powerpc/include/asm/hw_irq.h
View File

@ -142,10 +142,17 @@ static inline unsigned long get_perf_counter_pending(void)
return x;
}
static inline void set_perf_counter_pending(int x)
static inline void set_perf_counter_pending(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (x),
"r" (1),
"i" (offsetof(struct paca_struct, perf_counter_pending)));
}
static inline void clear_perf_counter_pending(void)
{
asm volatile("stb %0,%1(13)" : :
"r" (0),
"i" (offsetof(struct paca_struct, perf_counter_pending)));
}
@ -158,7 +165,8 @@ static inline unsigned long get_perf_counter_pending(void)
return 0;
}
static inline void set_perf_counter_pending(int x) {}
static inline void set_perf_counter_pending(void) {}
static inline void clear_perf_counter_pending(void) {}
static inline void perf_counter_do_pending(void) {}
#endif /* CONFIG_PERF_COUNTERS */

11
arch/powerpc/kernel/irq.c
View File

@ -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;

3
arch/powerpc/kernel/perf_counter.c
View File

@ -653,7 +653,6 @@ void perf_counter_do_pending(void)
struct cpu_hw_counters *cpuhw = &__get_cpu_var(cpu_hw_counters);
struct perf_counter *counter;
set_perf_counter_pending(0);
for (i = 0; i < cpuhw->n_counters; ++i) {
counter = cpuhw->counter[i];
if (counter && counter->wakeup_pending) {
@ -811,7 +810,7 @@ static void perf_counter_interrupt(struct pt_regs *regs)
perf_counter_do_pending();
irq_exit();
} else {
set_perf_counter_pending(1);
set_perf_counter_pending();
}
}
}

3
arch/x86/include/asm/perf_counter.h
View File

@ -84,6 +84,9 @@ union cpuid10_edx {
#define MSR_ARCH_PERFMON_FIXED_CTR2 0x30b
#define X86_PMC_IDX_FIXED_BUS_CYCLES (X86_PMC_IDX_FIXED + 2)
#define set_perf_counter_pending() \
set_tsk_thread_flag(current, TIF_PERF_COUNTERS);
#ifdef CONFIG_PERF_COUNTERS
extern void init_hw_perf_counters(void);
extern void perf_counters_lapic_init(int nmi);

2
kernel/perf_counter.c
View File

@ -1433,7 +1433,7 @@ static void perf_swcounter_interrupt(struct perf_counter *counter,
if (nmi) {
counter->wakeup_pending = 1;
set_tsk_thread_flag(current, TIF_PERF_COUNTERS);
set_perf_counter_pending();
} else
wake_up(&counter->waitq);
}