perf_counter: abstract wakeup flag setting in core to fix powerpc build
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>
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 0d2e37c..469e963 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -104,13 +104,6 @@
: : "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 @@
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;
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c
index 0e33d27..5008762 100644
--- a/arch/powerpc/kernel/perf_counter.c
+++ b/arch/powerpc/kernel/perf_counter.c
@@ -653,7 +653,6 @@
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 @@
perf_counter_do_pending();
irq_exit();
} else {
- set_perf_counter_pending(1);
+ set_perf_counter_pending();
}
}
}