From 2e41f91d9e90e34254746fefcb7bb678a3c9d541 Mon Sep 17 00:00:00 2001 From: Jaidev Patwardhan Date: Fri, 10 Jul 2009 02:06:00 -0700 Subject: MIPS: SMTC: Avoid queing multiple reschedule IPIs Signed-off-by: Chris Dearman Signed-off-by: Ralf Baechle --- arch/mips/include/asm/smtc_ipi.h | 1 + arch/mips/kernel/smtc.c | 34 ++++++++++++++++++++++++++++++---- 2 files changed, 31 insertions(+), 4 deletions(-) (limited to 'arch/mips') diff --git a/arch/mips/include/asm/smtc_ipi.h b/arch/mips/include/asm/smtc_ipi.h index 8ce517574340..15278dbd7e79 100644 --- a/arch/mips/include/asm/smtc_ipi.h +++ b/arch/mips/include/asm/smtc_ipi.h @@ -45,6 +45,7 @@ struct smtc_ipi_q { spinlock_t lock; struct smtc_ipi *tail; int depth; + int resched_flag; /* reschedule already queued */ }; static inline void smtc_ipi_nq(struct smtc_ipi_q *q, struct smtc_ipi *p) diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c index 4d181df44a40..24630fd8ef60 100644 --- a/arch/mips/kernel/smtc.c +++ b/arch/mips/kernel/smtc.c @@ -75,7 +75,6 @@ unsigned long irq_hwmask[NR_IRQS]; asiduse smtc_live_asid[MAX_SMTC_TLBS][MAX_SMTC_ASIDS]; - /* * Number of InterProcessor Interrupt (IPI) message buffers to allocate */ @@ -388,6 +387,7 @@ void smtc_prepare_cpus(int cpus) IPIQ[i].head = IPIQ[i].tail = NULL; spin_lock_init(&IPIQ[i].lock); IPIQ[i].depth = 0; + IPIQ[i].resched_flag = 0; /* No reschedules queued initially */ } /* cpu_data index starts at zero */ @@ -741,11 +741,24 @@ void smtc_forward_irq(unsigned int irq) static void smtc_ipi_qdump(void) { int i; + struct smtc_ipi *temp; for (i = 0; i < NR_CPUS ;i++) { - printk("IPIQ[%d]: head = 0x%x, tail = 0x%x, depth = %d\n", + pr_info("IPIQ[%d]: head = 0x%x, tail = 0x%x, depth = %d\n", i, (unsigned)IPIQ[i].head, (unsigned)IPIQ[i].tail, IPIQ[i].depth); + temp = IPIQ[i].head; + + while (temp != IPIQ[i].tail) { + pr_debug("%d %d %d: ", temp->type, temp->dest, + (int)temp->arg); +#ifdef SMTC_IPI_DEBUG + pr_debug("%u %lu\n", temp->sender, temp->stamp); +#else + pr_debug("\n"); +#endif + temp = temp->flink; + } } } @@ -784,11 +797,16 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) int mtflags; unsigned long tcrestart; extern void r4k_wait_irqoff(void), __pastwait(void); + int set_resched_flag = (type == LINUX_SMP_IPI && + action == SMP_RESCHEDULE_YOURSELF); if (cpu == smp_processor_id()) { printk("Cannot Send IPI to self!\n"); return; } + if (set_resched_flag && IPIQ[cpu].resched_flag != 0) + return; /* There is a reschedule queued already */ + /* Set up a descriptor, to be delivered either promptly or queued */ pipi = smtc_ipi_dq(&freeIPIq); if (pipi == NULL) { @@ -801,6 +819,7 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) pipi->dest = cpu; if (cpu_data[cpu].vpe_id != cpu_data[smp_processor_id()].vpe_id) { /* If not on same VPE, enqueue and send cross-VPE interrupt */ + IPIQ[cpu].resched_flag |= set_resched_flag; smtc_ipi_nq(&IPIQ[cpu], pipi); LOCK_CORE_PRA(); settc(cpu_data[cpu].tc_id); @@ -847,6 +866,7 @@ void smtc_send_ipi(int cpu, int type, unsigned int action) */ write_tc_c0_tchalt(0); UNLOCK_CORE_PRA(); + IPIQ[cpu].resched_flag |= set_resched_flag; smtc_ipi_nq(&IPIQ[cpu], pipi); } else { postdirect: @@ -996,12 +1016,15 @@ void deferred_smtc_ipi(void) * already enabled. */ local_irq_save(flags); - spin_lock(&q->lock); pipi = __smtc_ipi_dq(q); spin_unlock(&q->lock); - if (pipi != NULL) + if (pipi != NULL) { + if (pipi->type == LINUX_SMP_IPI && + (int)pipi->arg == SMP_RESCHEDULE_YOURSELF) + IPIQ[cpu].resched_flag = 0; ipi_decode(pipi); + } /* * The use of the __raw_local restore isn't * as obviously necessary here as in smtc_ipi_replay(), @@ -1082,6 +1105,9 @@ static irqreturn_t ipi_interrupt(int irq, void *dev_idm) * with interrupts off */ local_irq_save(flags); + if (pipi->type == LINUX_SMP_IPI && + (int)pipi->arg == SMP_RESCHEDULE_YOURSELF) + IPIQ[cpu].resched_flag = 0; ipi_decode(pipi); local_irq_restore(flags); } -- cgit v1.2.3