For future rework of try_to_wake_up() we'd like to push part of that
onto the CPU the task is actually going to run on, in order to do so we
need a generic callback from the existing scheduler IPI.
This patch introduces such a generic callback: scheduler_ipi() and
implements it as a NOP.
BenH notes: PowerPC might use this IPI on offline CPUs under rare
conditions!!
Acked-by: Russell King <[email protected]>
Acked-by: Martin Schwidefsky <[email protected]>
Acked-by: Chris Metcalf <[email protected]>
Acked-by: Jesper Nilsson <[email protected]>
Acked-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Ralf Baechle <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
LKML-Reference: <new-submission>
---
arch/alpha/kernel/smp.c | 3 +--
arch/arm/kernel/smp.c | 5 +----
arch/blackfin/mach-common/smp.c | 3 +++
arch/cris/arch-v32/kernel/smp.c | 13 ++++++++-----
arch/ia64/kernel/irq_ia64.c | 2 ++
arch/ia64/xen/irq_xen.c | 10 +++++++++-
arch/m32r/kernel/smp.c | 4 +---
arch/mips/cavium-octeon/smp.c | 2 ++
arch/mips/kernel/smtc.c | 2 +-
arch/mips/mti-malta/malta-int.c | 2 ++
arch/mips/pmc-sierra/yosemite/smp.c | 4 ++++
arch/mips/sgi-ip27/ip27-irq.c | 2 ++
arch/mips/sibyte/bcm1480/smp.c | 7 +++----
arch/mips/sibyte/sb1250/smp.c | 7 +++----
arch/mn10300/kernel/smp.c | 5 +----
arch/parisc/kernel/smp.c | 5 +----
arch/powerpc/kernel/smp.c | 3 ++-
arch/s390/kernel/smp.c | 6 +++---
arch/sh/kernel/smp.c | 2 ++
arch/sparc/kernel/smp_32.c | 2 +-
arch/sparc/kernel/smp_64.c | 1 +
arch/tile/kernel/smp.c | 6 +-----
arch/um/kernel/smp.c | 2 +-
arch/x86/kernel/smp.c | 5 ++---
arch/x86/xen/smp.c | 5 ++---
include/linux/sched.h | 1 +
26 files changed, 60 insertions(+), 49 deletions(-)
Index: linux-2.6/arch/alpha/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/alpha/kernel/smp.c
+++ linux-2.6/arch/alpha/kernel/smp.c
@@ -585,8 +585,7 @@ handle_ipi(struct pt_regs *regs)
switch (which) {
case IPI_RESCHEDULE:
- /* Reschedule callback. Everything to be done
- is done by the interrupt return path. */
+ scheduler_ipi();
break;
case IPI_CALL_FUNC:
Index: linux-2.6/arch/arm/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/arm/kernel/smp.c
+++ linux-2.6/arch/arm/kernel/smp.c
@@ -561,10 +561,7 @@ asmlinkage void __exception_irq_entry do
break;
case IPI_RESCHEDULE:
- /*
- * nothing more to do - eveything is
- * done on the interrupt return path
- */
+ scheduler_ipi();
break;
case IPI_CALL_FUNC:
Index: linux-2.6/arch/blackfin/mach-common/smp.c
===================================================================
--- linux-2.6.orig/arch/blackfin/mach-common/smp.c
+++ linux-2.6/arch/blackfin/mach-common/smp.c
@@ -160,6 +160,9 @@ static irqreturn_t ipi_handler_int1(int
while (msg_queue->count) {
msg = &msg_queue->ipi_message[msg_queue->head];
switch (msg->type) {
+ case BFIN_IPI_RESCHEDULE:
+ scheduler_ipi();
+ break;
case BFIN_IPI_CALL_FUNC:
spin_unlock_irqrestore(&msg_queue->lock, flags);
ipi_call_function(cpu, msg);
Index: linux-2.6/arch/cris/arch-v32/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/cris/arch-v32/kernel/smp.c
+++ linux-2.6/arch/cris/arch-v32/kernel/smp.c
@@ -342,15 +342,18 @@ irqreturn_t crisv32_ipi_interrupt(int ir
ipi = REG_RD(intr_vect, irq_regs[smp_processor_id()], rw_ipi);
+ if (ipi.vector & IPI_SCHEDULE) {
+ scheduler_ipi();
+ }
if (ipi.vector & IPI_CALL) {
- func(info);
+ func(info);
}
if (ipi.vector & IPI_FLUSH_TLB) {
- if (flush_mm == FLUSH_ALL)
- __flush_tlb_all();
- else if (flush_vma == FLUSH_ALL)
+ if (flush_mm == FLUSH_ALL)
+ __flush_tlb_all();
+ else if (flush_vma == FLUSH_ALL)
__flush_tlb_mm(flush_mm);
- else
+ else
__flush_tlb_page(flush_vma, flush_addr);
}
Index: linux-2.6/arch/ia64/kernel/irq_ia64.c
===================================================================
--- linux-2.6.orig/arch/ia64/kernel/irq_ia64.c
+++ linux-2.6/arch/ia64/kernel/irq_ia64.c
@@ -31,6 +31,7 @@
#include <linux/irq.h>
#include <linux/ratelimit.h>
#include <linux/acpi.h>
+#include <linux/sched.h>
#include <asm/delay.h>
#include <asm/intrinsics.h>
@@ -496,6 +497,7 @@ ia64_handle_irq (ia64_vector vector, str
smp_local_flush_tlb();
kstat_incr_irqs_this_cpu(irq, desc);
} else if (unlikely(IS_RESCHEDULE(vector))) {
+ scheduler_ipi();
kstat_incr_irqs_this_cpu(irq, desc);
} else {
ia64_setreg(_IA64_REG_CR_TPR, vector);
Index: linux-2.6/arch/ia64/xen/irq_xen.c
===================================================================
--- linux-2.6.orig/arch/ia64/xen/irq_xen.c
+++ linux-2.6/arch/ia64/xen/irq_xen.c
@@ -92,6 +92,8 @@ static unsigned short saved_irq_cnt;
static int xen_slab_ready;
#ifdef CONFIG_SMP
+#include <linux/sched.h>
+
/* Dummy stub. Though we may check XEN_RESCHEDULE_VECTOR before __do_IRQ,
* it ends up to issue several memory accesses upon percpu data and
* thus adds unnecessary traffic to other paths.
@@ -99,7 +101,13 @@ static int xen_slab_ready;
static irqreturn_t
xen_dummy_handler(int irq, void *dev_id)
{
+ return IRQ_HANDLED;
+}
+static irqreturn_t
+xen_resched_handler(int irq, void *dev_id)
+{
+ scheduler_ipi();
return IRQ_HANDLED;
}
@@ -110,7 +118,7 @@ static struct irqaction xen_ipi_irqactio
};
static struct irqaction xen_resched_irqaction = {
- .handler = xen_dummy_handler,
+ .handler = xen_resched_handler,
.flags = IRQF_DISABLED,
.name = "resched"
};
Index: linux-2.6/arch/m32r/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/m32r/kernel/smp.c
+++ linux-2.6/arch/m32r/kernel/smp.c
@@ -122,8 +122,6 @@ void smp_send_reschedule(int cpu_id)
*
* Description: This routine executes on CPU which received
* 'RESCHEDULE_IPI'.
- * Rescheduling is processed at the exit of interrupt
- * operation.
*
* Born on Date: 2002.02.05
*
@@ -138,7 +136,7 @@ void smp_send_reschedule(int cpu_id)
*==========================================================================*/
void smp_reschedule_interrupt(void)
{
- /* nothing to do */
+ scheduler_ipi();
}
/*==========================================================================*
Index: linux-2.6/arch/mips/kernel/smtc.c
===================================================================
--- linux-2.6.orig/arch/mips/kernel/smtc.c
+++ linux-2.6/arch/mips/kernel/smtc.c
@@ -930,7 +930,7 @@ static void post_direct_ipi(int cpu, str
static void ipi_resched_interrupt(void)
{
- /* Return from interrupt should be enough to cause scheduler check */
+ scheduler_ipi();
}
static void ipi_call_interrupt(void)
Index: linux-2.6/arch/mips/sibyte/bcm1480/smp.c
===================================================================
--- linux-2.6.orig/arch/mips/sibyte/bcm1480/smp.c
+++ linux-2.6/arch/mips/sibyte/bcm1480/smp.c
@@ -20,6 +20,7 @@
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
+#include <linux/sched.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
@@ -189,10 +190,8 @@ void bcm1480_mailbox_interrupt(void)
/* Clear the mailbox to clear the interrupt */
__raw_writeq(((u64)action)<<48, mailbox_0_clear_regs[cpu]);
- /*
- * Nothing to do for SMP_RESCHEDULE_YOURSELF; returning from the
- * interrupt will do the reschedule for us
- */
+ if (action & SMP_RESCHEDULE_YOURSELF)
+ scheduler_ipi();
if (action & SMP_CALL_FUNCTION)
smp_call_function_interrupt();
Index: linux-2.6/arch/mips/sibyte/sb1250/smp.c
===================================================================
--- linux-2.6.orig/arch/mips/sibyte/sb1250/smp.c
+++ linux-2.6/arch/mips/sibyte/sb1250/smp.c
@@ -21,6 +21,7 @@
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
+#include <linux/sched.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
@@ -177,10 +178,8 @@ void sb1250_mailbox_interrupt(void)
/* Clear the mailbox to clear the interrupt */
____raw_writeq(((u64)action) << 48, mailbox_clear_regs[cpu]);
- /*
- * Nothing to do for SMP_RESCHEDULE_YOURSELF; returning from the
- * interrupt will do the reschedule for us
- */
+ if (action & SMP_RESCHEDULE_YOURSELF)
+ scheduler_ipi();
if (action & SMP_CALL_FUNCTION)
smp_call_function_interrupt();
Index: linux-2.6/arch/mn10300/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/mn10300/kernel/smp.c
+++ linux-2.6/arch/mn10300/kernel/smp.c
@@ -464,14 +464,11 @@ void smp_send_stop(void)
* @irq: The interrupt number.
* @dev_id: The device ID.
*
- * We need do nothing here, since the scheduling will be effected on our way
- * back through entry.S.
- *
* Returns IRQ_HANDLED to indicate we handled the interrupt successfully.
*/
static irqreturn_t smp_reschedule_interrupt(int irq, void *dev_id)
{
- /* do nothing */
+ scheduler_ipi();
return IRQ_HANDLED;
}
Index: linux-2.6/arch/parisc/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/parisc/kernel/smp.c
+++ linux-2.6/arch/parisc/kernel/smp.c
@@ -155,10 +155,7 @@ ipi_interrupt(int irq, void *dev_id)
case IPI_RESCHEDULE:
smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
- /*
- * Reschedule callback. Everything to be
- * done is done by the interrupt return path.
- */
+ scheduler_ipi();
break;
case IPI_CALL_FUNC:
Index: linux-2.6/arch/powerpc/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/smp.c
+++ linux-2.6/arch/powerpc/kernel/smp.c
@@ -98,6 +98,7 @@ void smp_message_recv(int msg)
break;
case PPC_MSG_RESCHEDULE:
/* we notice need_resched on exit */
+ scheduler_ipi();
break;
case PPC_MSG_CALL_FUNC_SINGLE:
generic_smp_call_function_single_interrupt();
@@ -127,7 +128,7 @@ static irqreturn_t call_function_action(
static irqreturn_t reschedule_action(int irq, void *data)
{
- /* we just need the return path side effect of checking need_resched */
+ scheduler_ipi();
return IRQ_HANDLED;
}
Index: linux-2.6/arch/s390/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/s390/kernel/smp.c
+++ linux-2.6/arch/s390/kernel/smp.c
@@ -165,12 +165,12 @@ static void do_ext_call_interrupt(unsign
kstat_cpu(smp_processor_id()).irqs[EXTINT_IPI]++;
/*
* handle bit signal external calls
- *
- * For the ec_schedule signal we have to do nothing. All the work
- * is done automatically when we return from the interrupt.
*/
bits = xchg(&S390_lowcore.ext_call_fast, 0);
+ if (test_bit(ec_schedule, &bits))
+ scheduler_ipi();
+
if (test_bit(ec_call_function, &bits))
generic_smp_call_function_interrupt();
Index: linux-2.6/arch/sh/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/sh/kernel/smp.c
+++ linux-2.6/arch/sh/kernel/smp.c
@@ -20,6 +20,7 @@
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
+#include <linux/sched.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/system.h>
@@ -323,6 +324,7 @@ void smp_message_recv(unsigned int msg)
generic_smp_call_function_interrupt();
break;
case SMP_MSG_RESCHEDULE:
+ scheduler_ipi();
break;
case SMP_MSG_FUNCTION_SINGLE:
generic_smp_call_function_single_interrupt();
Index: linux-2.6/arch/sparc/kernel/smp_32.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/smp_32.c
+++ linux-2.6/arch/sparc/kernel/smp_32.c
@@ -125,7 +125,7 @@ struct linux_prom_registers smp_penguin_
void smp_send_reschedule(int cpu)
{
- /* See sparc64 */
+ scheduler_ipi();
}
void smp_send_stop(void)
Index: linux-2.6/arch/sparc/kernel/smp_64.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/smp_64.c
+++ linux-2.6/arch/sparc/kernel/smp_64.c
@@ -1369,6 +1369,7 @@ void smp_send_reschedule(int cpu)
void __irq_entry smp_receive_signal_client(int irq, struct pt_regs *regs)
{
clear_softint(1 << irq);
+ scheduler_ipi();
}
/* This is a nop because we capture all other cpus
Index: linux-2.6/arch/tile/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/tile/kernel/smp.c
+++ linux-2.6/arch/tile/kernel/smp.c
@@ -184,12 +184,8 @@ void flush_icache_range(unsigned long st
/* Called when smp_send_reschedule() triggers IRQ_RESCHEDULE. */
static irqreturn_t handle_reschedule_ipi(int irq, void *token)
{
- /*
- * Nothing to do here; when we return from interrupt, the
- * rescheduling will occur there. But do bump the interrupt
- * profiler count in the meantime.
- */
__get_cpu_var(irq_stat).irq_resched_count++;
+ scheduler_ipi();
return IRQ_HANDLED;
}
Index: linux-2.6/arch/um/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/um/kernel/smp.c
+++ linux-2.6/arch/um/kernel/smp.c
@@ -173,7 +173,7 @@ void IPI_handler(int cpu)
break;
case 'R':
- set_tsk_need_resched(current);
+ scheduler_ipi();
break;
case 'S':
Index: linux-2.6/arch/x86/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/smp.c
+++ linux-2.6/arch/x86/kernel/smp.c
@@ -194,14 +194,13 @@ static void native_stop_other_cpus(int w
}
/*
- * Reschedule call back. Nothing to do,
- * all the work is done automatically when
- * we return from the interrupt.
+ * Reschedule call back.
*/
void smp_reschedule_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
inc_irq_stat(irq_resched_count);
+ scheduler_ipi();
/*
* KVM uses this interrupt to force a cpu out of guest mode
*/
Index: linux-2.6/arch/x86/xen/smp.c
===================================================================
--- linux-2.6.orig/arch/x86/xen/smp.c
+++ linux-2.6/arch/x86/xen/smp.c
@@ -46,13 +46,12 @@ static irqreturn_t xen_call_function_int
static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
/*
- * Reschedule call back. Nothing to do,
- * all the work is done automatically when
- * we return from the interrupt.
+ * Reschedule call back.
*/
static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
{
inc_irq_stat(irq_resched_count);
+ scheduler_ipi();
return IRQ_HANDLED;
}
Index: linux-2.6/include/linux/sched.h
===================================================================
--- linux-2.6.orig/include/linux/sched.h
+++ linux-2.6/include/linux/sched.h
@@ -2182,6 +2182,7 @@ extern void set_task_comm(struct task_st
extern char *get_task_comm(char *to, struct task_struct *tsk);
#ifdef CONFIG_SMP
+static inline void scheduler_ipi(void) { }
extern unsigned long wait_task_inactive(struct task_struct *, long match_state);
#else
static inline unsigned long wait_task_inactive(struct task_struct *p,
Index: linux-2.6/arch/mips/cavium-octeon/smp.c
===================================================================
--- linux-2.6.orig/arch/mips/cavium-octeon/smp.c
+++ linux-2.6/arch/mips/cavium-octeon/smp.c
@@ -44,6 +44,8 @@ static irqreturn_t mailbox_interrupt(int
if (action & SMP_CALL_FUNCTION)
smp_call_function_interrupt();
+ if (action & SMP_RESCHEDULE_YOURSELF)
+ scheduler_ipi();
/* Check if we've been told to flush the icache */
if (action & SMP_ICACHE_FLUSH)
Index: linux-2.6/arch/mips/mti-malta/malta-int.c
===================================================================
--- linux-2.6.orig/arch/mips/mti-malta/malta-int.c
+++ linux-2.6/arch/mips/mti-malta/malta-int.c
@@ -309,6 +309,8 @@ static void ipi_call_dispatch(void)
static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
{
+ scheduler_ipi();
+
return IRQ_HANDLED;
}
Index: linux-2.6/arch/mips/pmc-sierra/yosemite/smp.c
===================================================================
--- linux-2.6.orig/arch/mips/pmc-sierra/yosemite/smp.c
+++ linux-2.6/arch/mips/pmc-sierra/yosemite/smp.c
@@ -55,6 +55,8 @@ void titan_mailbox_irq(void)
if (status & 0x2)
smp_call_function_interrupt();
+ if (status & 0x4)
+ scheduler_ipi();
break;
case 1:
@@ -63,6 +65,8 @@ void titan_mailbox_irq(void)
if (status & 0x2)
smp_call_function_interrupt();
+ if (status & 0x4)
+ scheduler_ipi();
break;
}
}
Index: linux-2.6/arch/mips/sgi-ip27/ip27-irq.c
===================================================================
--- linux-2.6.orig/arch/mips/sgi-ip27/ip27-irq.c
+++ linux-2.6/arch/mips/sgi-ip27/ip27-irq.c
@@ -147,8 +147,10 @@ static void ip27_do_irq_mask0(void)
#ifdef CONFIG_SMP
if (pend0 & (1UL << CPU_RESCHED_A_IRQ)) {
LOCAL_HUB_CLR_INTR(CPU_RESCHED_A_IRQ);
+ scheduler_ipi();
} else if (pend0 & (1UL << CPU_RESCHED_B_IRQ)) {
LOCAL_HUB_CLR_INTR(CPU_RESCHED_B_IRQ);
+ scheduler_ipi();
} else if (pend0 & (1UL << CPU_CALL_A_IRQ)) {
LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ);
smp_call_function_interrupt();
On 03/02/11 09:38, Peter Zijlstra wrote:
> For future rework of try_to_wake_up() we'd like to push part of that
> onto the CPU the task is actually going to run on, in order to do so we
> need a generic callback from the existing scheduler IPI.
>
> This patch introduces such a generic callback: scheduler_ipi() and
> implements it as a NOP.
>
> BenH notes: PowerPC might use this IPI on offline CPUs under rare
> conditions!!
>
> Acked-by: Russell King <[email protected]>
> Acked-by: Martin Schwidefsky <[email protected]>
> Acked-by: Chris Metcalf <[email protected]>
> Acked-by: Jesper Nilsson <[email protected]>
> Acked-by: Benjamin Herrenschmidt <[email protected]>
> Signed-off-by: Ralf Baechle <[email protected]>
> Signed-off-by: Peter Zijlstra <[email protected]>
> LKML-Reference: <new-submission>
> ---
> arch/alpha/kernel/smp.c | 3 +--
> arch/arm/kernel/smp.c | 5 +----
> arch/blackfin/mach-common/smp.c | 3 +++
> arch/cris/arch-v32/kernel/smp.c | 13 ++++++++-----
> arch/ia64/kernel/irq_ia64.c | 2 ++
> arch/ia64/xen/irq_xen.c | 10 +++++++++-
> arch/m32r/kernel/smp.c | 4 +---
> arch/mips/cavium-octeon/smp.c | 2 ++
> arch/mips/kernel/smtc.c | 2 +-
> arch/mips/mti-malta/malta-int.c | 2 ++
> arch/mips/pmc-sierra/yosemite/smp.c | 4 ++++
> arch/mips/sgi-ip27/ip27-irq.c | 2 ++
> arch/mips/sibyte/bcm1480/smp.c | 7 +++----
> arch/mips/sibyte/sb1250/smp.c | 7 +++----
> arch/mn10300/kernel/smp.c | 5 +----
> arch/parisc/kernel/smp.c | 5 +----
> arch/powerpc/kernel/smp.c | 3 ++-
> arch/s390/kernel/smp.c | 6 +++---
> arch/sh/kernel/smp.c | 2 ++
> arch/sparc/kernel/smp_32.c | 2 +-
> arch/sparc/kernel/smp_64.c | 1 +
> arch/tile/kernel/smp.c | 6 +-----
> arch/um/kernel/smp.c | 2 +-
> arch/x86/kernel/smp.c | 5 ++---
> arch/x86/xen/smp.c | 5 ++---
> include/linux/sched.h | 1 +
> 26 files changed, 60 insertions(+), 49 deletions(-)
>
< snip >
In this patch the tabs turned into spaces. (None of the other
patches have this problem.)
> Index: linux-2.6/arch/sparc/kernel/smp_32.c
> ===================================================================
> --- linux-2.6.orig/arch/sparc/kernel/smp_32.c
> +++ linux-2.6/arch/sparc/kernel/smp_32.c
> @@ -125,7 +125,7 @@ struct linux_prom_registers smp_penguin_
>
> void smp_send_reschedule(int cpu)
> {
> - /* See sparc64 */
> + scheduler_ipi();
> }
If I understand correctly, this is calling scheduler_ipi() on the
cpu that should be sending an IPI, not on the cpu receiving the IPI.
If so, smp_send_reschedule() needs to send an IPI, and the scheduler_ipi()
put in the place where the IPI is processed.
-Frank
On Wed, 02 Mar 2011 17:38:32 -0000, To: Peter Zijlstra wrote:
> For future rework of try_to_wake_up() we'd like to push part of that
> onto the CPU the task is actually going to run on, in order to do so we
> need a generic callback from the existing scheduler IPI.
>
> This patch introduces such a generic callback: scheduler_ipi() and
> implements it as a NOP.
>
> BenH notes: PowerPC might use this IPI on offline CPUs under rare
> conditions!!
..
> Index: linux-2.6/arch/powerpc/kernel/smp.c
> ===================================================================
> --- linux-2.6.orig/arch/powerpc/kernel/smp.c
> +++ linux-2.6/arch/powerpc/kernel/smp.c
> @@ -98,6 +98,7 @@ void smp_message_recv(int msg)
> break;
> case PPC_MSG_RESCHEDULE:
> /* we notice need_resched on exit */
This comment should also be removed, as it was documenting the empty action.
> + scheduler_ipi();
> break;
> case PPC_MSG_CALL_FUNC_SINGLE:
> generic_smp_call_function_single_interrupt();
> @@ -127,7 +128,7 @@ static irqreturn_t call_function_action(
>
> static irqreturn_t reschedule_action(int irq, void *data)
> {
> - /* we just need the return path side effect of checking need_resched */
> + scheduler_ipi();
> return IRQ_HANDLED;
> }
>
Thanks,
milton
On Fri, 2011-03-11 at 09:07 -0600, Milton Miller wrote:
> > case PPC_MSG_RESCHEDULE:
> > /* we notice need_resched on exit */
>
> This comment should also be removed, as it was documenting the empty
> action.
But its still true, TIF_NEED_RESCHED isn't going away and we still
notice that on the interrupt return path.
On Fri, 11 Mar 2011 16:27:27 +0100, Peter Zijlstra wrote:
>
> On Fri, 2011-03-11 at 09:07 -0600, Milton Miller wrote:
> > > case PPC_MSG_RESCHEDULE:
> > > /* we notice need_resched on exit */
> > > + smp_reschedule_ipi()
> >
> > This comment should also be removed, as it was documenting the empty
> > action.
>
> But its still true, TIF_NEED_RESCHED isn't going away and we still
> notice that on the interrupt return path.
Just because it is true does not mean it is useful. Why is this site
different than the twenty odd other call sites that it needs to document
the behaivors requried upon exiting the kernel from interrupt deep in this
interrupt handling call path? Why is it not placed after the call, where
it would talk about what happens next instead of what will happen later?
For that matter, what does on exit mean?
I went ahead and sent this when I saw the comments questioning the
sparc 32 part of the patch and thought you might respin. But if this is
already committed then I will submit a followup patch for consideration
after this is merged.
milton
On Mon, 2011-03-14 at 21:59 -0600, Milton Miller wrote:
>
> I went ahead and sent this when I saw the comments questioning the
> sparc 32 part of the patch and thought you might respin. But if this is
> already committed then I will submit a followup patch for consideration
> after this is merged.
No, its not yet committed, and I do indeed need to respin. If you want
that comment gone, consider it so :-)
On Thu, 2011-03-10 at 17:36 -0800, Frank Rowand wrote:
>
> > Index: linux-2.6/arch/sparc/kernel/smp_32.c
> > ===================================================================
> > --- linux-2.6.orig/arch/sparc/kernel/smp_32.c
> > +++ linux-2.6/arch/sparc/kernel/smp_32.c
> > @@ -125,7 +125,7 @@ struct linux_prom_registers smp_penguin_
> >
> > void smp_send_reschedule(int cpu)
> > {
> > - /* See sparc64 */
> > + scheduler_ipi();
> > }
>
> If I understand correctly, this is calling scheduler_ipi() on the
> cpu that should be sending an IPI, not on the cpu receiving the IPI.
> If so, smp_send_reschedule() needs to send an IPI, and the scheduler_ipi()
> put in the place where the IPI is processed.
Yes, D'0h.. Dave how does sparc32 work here? There appears to be an ipi
missing.