From: Mikael Pettersson <mikpe@csd.uu.se>
- When a task is resumed, check if suspend recorded that an overflow
interrupt is pending. If so, handle the overflow and deliver the signal.
- Split interrupt handler in two parts: one used only for hardware
interrupts, and one also used for software-generated interrupts.
- Change signal generation code to not wake up the target task (==
current). Avoids lockups when the interrupt/signal is generated from
switch_to().
- Remove obsolete comment at vperfctr_suspend().
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/perfctr/virtual.c | 41 +++++++++++++++++++++++++++++++++-----
1 files changed, 36 insertions(+), 5 deletions(-)
diff -puN drivers/perfctr/virtual.c~perfctr-virtual-updates drivers/perfctr/virtual.c
--- 25/drivers/perfctr/virtual.c~perfctr-virtual-updates 2004-11-11 01:44:53.805265304 -0800
+++ 25-akpm/drivers/perfctr/virtual.c 2004-11-11 01:44:53.810264544 -0800
@@ -48,6 +48,7 @@ struct vperfctr {
#ifdef CONFIG_PERFCTR_INTERRUPT_SUPPORT
static void vperfctr_ihandler(unsigned long pc);
+static void vperfctr_handle_overflow(struct task_struct*, struct vperfctr*);
static inline void vperfctr_set_ihandler(void)
{
@@ -197,8 +198,6 @@ static void put_vperfctr(struct vperfctr
/* PRE: IS_RUNNING(perfctr)
* Suspend the counters.
- * XXX: When called from switch_to(), perfctr belongs to 'prev'
- * but current is 'next'.
*/
static inline void vperfctr_suspend(struct vperfctr *perfctr)
{
@@ -220,6 +219,18 @@ static inline void vperfctr_resume(struc
vperfctr_reset_sampling_timer(perfctr);
}
+static inline void vperfctr_resume_with_overflow_check(struct vperfctr *perfctr)
+{
+#ifdef CONFIG_PERFCTR_INTERRUPT_SUPPORT
+ if (perfctr->cpu_state.pending_interrupt) {
+ perfctr->cpu_state.pending_interrupt = 0;
+ vperfctr_handle_overflow(current, perfctr);
+ return;
+ }
+#endif
+ vperfctr_resume(perfctr);
+}
+
/* Sample the counters but do not suspend them. */
static void vperfctr_sample(struct vperfctr *perfctr)
{
@@ -236,8 +247,6 @@ static void vperfctr_ihandler(unsigned l
{
struct task_struct *tsk = current;
struct vperfctr *perfctr;
- unsigned int pmc_mask;
- siginfo_t si;
perfctr = tsk->thread.perfctr;
if (!perfctr) {
@@ -251,6 +260,16 @@ static void vperfctr_ihandler(unsigned l
return;
}
vperfctr_suspend(perfctr);
+ vperfctr_handle_overflow(tsk, perfctr);
+}
+
+static void vperfctr_handle_overflow(struct task_struct *tsk,
+ struct vperfctr *perfctr)
+{
+ unsigned int pmc_mask;
+ siginfo_t si;
+ sigset_t old_blocked;
+
pmc_mask = perfctr_cpu_identify_overflow(&perfctr->cpu_state);
if (!pmc_mask) {
printk(KERN_ERR "%s: BUG! pid %d has unidentifiable overflow source\n",
@@ -269,8 +288,20 @@ static void vperfctr_ihandler(unsigned l
si.si_errno = 0;
si.si_code = SI_PMC_OVF;
si.si_pmc_ovf_mask = pmc_mask;
+
+ /* deliver signal without waking up the receiver */
+ spin_lock_irq(&tsk->sighand->siglock);
+ old_blocked = tsk->blocked;
+ sigaddset(&tsk->blocked, si.si_signo);
+ spin_unlock_irq(&tsk->sighand->siglock);
+
if (!send_sig_info(si.si_signo, &si, tsk))
send_sig(si.si_signo, tsk, 1);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ tsk->blocked = old_blocked;
+ recalc_sigpending();
+ spin_unlock_irq(&tsk->sighand->siglock);
}
#endif
@@ -341,7 +372,7 @@ void __vperfctr_resume(struct vperfctr *
return;
}
#endif
- vperfctr_resume(perfctr);
+ vperfctr_resume_with_overflow_check(perfctr);
}
}
_