Commit 184748cc authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

sched: Provide scheduler_ipi() callback in response to smp_send_reschedule()

For future rework of try_to_wake_up() we'd like to push part of that
function 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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: default avatarChris Metcalf <cmetcalf@tilera.com>
Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
Reviewed-by: default avatarFrank Rowand <frank.rowand@am.sony.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110405152728.744338123@chello.nl
parent a4c98f8b
......@@ -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:
......
......@@ -560,10 +560,7 @@ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
break;
case IPI_RESCHEDULE:
/*
* nothing more to do - eveything is
* done on the interrupt return path
*/
scheduler_ipi();
break;
case IPI_CALL_FUNC:
......
......@@ -164,6 +164,9 @@ static irqreturn_t ipi_handler_int1(int irq, void *dev_instance)
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);
......
......@@ -342,15 +342,18 @@ irqreturn_t crisv32_ipi_interrupt(int irq, void *dev_id)
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);
}
......
......@@ -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, struct pt_regs *regs)
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);
......
......@@ -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_irqaction = {
};
static struct irqaction xen_resched_irqaction = {
.handler = xen_dummy_handler,
.handler = xen_resched_handler,
.flags = IRQF_DISABLED,
.name = "resched"
};
......
......@@ -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();
}
/*==========================================================================*
......
......@@ -44,6 +44,8 @@ static irqreturn_t mailbox_interrupt(int irq, void *dev_id)
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)
......
......@@ -929,7 +929,7 @@ static void post_direct_ipi(int cpu, struct smtc_ipi *pipi)
static void ipi_resched_interrupt(void)
{
/* Return from interrupt should be enough to cause scheduler check */
scheduler_ipi();
}
static void ipi_call_interrupt(void)
......
......@@ -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;
}
......
......@@ -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;
}
}
......
......@@ -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();
......
......@@ -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();
......
......@@ -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();
......
......@@ -494,14 +494,11 @@ 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;
}
......
......@@ -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:
......
......@@ -116,7 +116,7 @@ void smp_message_recv(int msg)
generic_smp_call_function_interrupt();
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();
......@@ -146,7 +146,7 @@ static irqreturn_t call_function_action(int irq, void *data)
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;
}
......
......@@ -165,12 +165,12 @@ static void do_ext_call_interrupt(unsigned int ext_int_code,
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();
......
......@@ -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();
......
......@@ -125,7 +125,9 @@ struct linux_prom_registers smp_penguin_ctable __cpuinitdata = { 0 };
void smp_send_reschedule(int cpu)
{
/* See sparc64 */
/*
* XXX missing reschedule IPI, see scheduler_ipi()
*/
}
void smp_send_stop(void)
......
......@@ -1368,6 +1368,7 @@ 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
......
......@@ -189,12 +189,8 @@ void flush_icache_range(unsigned long start, unsigned long end)
/* 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;
}
......
......@@ -173,7 +173,7 @@ void IPI_handler(int cpu)
break;
case 'R':
set_tsk_need_resched(current);
scheduler_ipi();
break;
case 'S':
......
......@@ -194,14 +194,13 @@ static void native_stop_other_cpus(int wait)
}
/*
* 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
*/
......
......@@ -46,13 +46,12 @@ static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
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;
}
......
......@@ -2189,8 +2189,10 @@ extern void set_task_comm(struct task_struct *tsk, char *from);
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 void scheduler_ipi(void) { }
static inline unsigned long wait_task_inactive(struct task_struct *p,
long match_state)
{
......
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