Peter Zijlstra wrote:
On Fri, 2011-05-20 at 08:07 +0200, Daniel Hellstrom wrote:
Peter Zijlstra wrote:
On Thu, 2011-05-19 at 15:37 +0200, Daniel Hellstrom wrote:
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 41102c5..d5b3958 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -156,11 +156,11 @@ void arch_send_call_function_ipi_mask(const struct
cpumask *mask)
void smp_resched_interrupt(void)
{
+ irq_enter();
+ scheduler_ipi();
local_cpu_data().irq_resched_count++;
- /*
- * do nothing, since it all was about calling re-schedule
- * routine called by interrupt return code.
- */
+ irq_exit();
+ /* re-schedule routine called by interrupt return code. */
}
That doesn't look like an IPI, that looks like its calls the function on
the local cpu, which is completely pointless.
The above function is one of the IPI interrupt handlers.
The smp_send_reschedule() is called by the generic code, it is
responsible for sending an IRQ to the target CPU, that CPU comes into
smp_resched_interrupt above from the IRQ trap handler. So yes, the
scheduler_ipi() is called on the local CPU, but on the CPU taking the
IPI not the CPU sending the IPI.
Ah, clearly I cannot read well, I actually thought that was
smp_send_reschedule(). OK, if sparc32 is now actually sending IPIs and
the above is the handler, then you're completely right, sorry for the
confusion.
Yes, my patches implements IPI for sparc32.
Also, since sparc32 now grew this IPI, you can remove:
+++ b/init/Kconfig
@@ -827,6 +827,11 @@ config SCHED_AUTOGROUP
desktop applications. Task group autogeneration is currently based
upon task session.
+config SCHED_TTWU_QUEUE
+ bool
+ depends on !SPARC32
+ default y
+
Do you think this is an acceptable patch? If so I will send these two
patches to the sparclinux list unless you think otherwise.
Thank you for enlightening this,
Daniel
Subject: [PATCH] SCHED_TTWU_QUEUE is not longer needed since sparc32 now
implements IPI
Signed-off-by: Daniel Hellstrom <daniel@xxxxxxxxxxx>
Reported-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
init/Kconfig | 5 -----
kernel/sched.c | 2 +-
2 files changed, 1 insertions(+), 6 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index df64627..a66b656 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -827,11 +827,6 @@ config SCHED_AUTOGROUP
desktop applications. Task group autogeneration is currently
based
upon task session.
-config SCHED_TTWU_QUEUE
- bool
- depends on !SPARC32
- default y
-
config MM_OWNER
bool
diff --git a/kernel/sched.c b/kernel/sched.c
index c62acf4..0516af4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2564,7 +2564,7 @@ static void ttwu_queue(struct task_struct *p, int cpu)
{
struct rq *rq = cpu_rq(cpu);
-#if defined(CONFIG_SMP) && defined(CONFIG_SCHED_TTWU_QUEUE)
+#if defined(CONFIG_SMP)
if (sched_feat(TTWU_QUEUE) && cpu != smp_processor_id()) {
ttwu_queue_remote(p, cpu);
return;
--
--
To unsubscribe from this list: send the line "unsubscribe linux-next" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
