From 3be44b9cc33d26930cb3bb014f35f582c6522481 Mon Sep 17 00:00:00 2001 From: Jack Steiner Date: Tue, 8 May 2007 14:50:43 -0700 Subject: [IA64] Optional method to purge the TLB on SN systems This patch adds an optional method for purging the TLB on SN IA64 systems. The change should not affect any non-SN system. Signed-off-by: Jack Steiner Signed-off-by: Tony Luck diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c index 456f57b..9a5f41b 100644 --- a/arch/ia64/kernel/irq_ia64.c +++ b/arch/ia64/kernel/irq_ia64.c @@ -39,6 +39,7 @@ #include #include #include +#include #ifdef CONFIG_PERFMON # include @@ -127,8 +128,10 @@ void destroy_irq(unsigned int irq) #ifdef CONFIG_SMP # define IS_RESCHEDULE(vec) (vec == IA64_IPI_RESCHEDULE) +# define IS_LOCAL_TLB_FLUSH(vec) (vec == IA64_IPI_LOCAL_TLB_FLUSH) #else # define IS_RESCHEDULE(vec) (0) +# define IS_LOCAL_TLB_FLUSH(vec) (0) #endif /* * That's where the IVT branches when we get an external @@ -180,8 +183,11 @@ ia64_handle_irq (ia64_vector vector, struct pt_regs *regs) saved_tpr = ia64_getreg(_IA64_REG_CR_TPR); ia64_srlz_d(); while (vector != IA64_SPURIOUS_INT_VECTOR) { - if (unlikely(IS_RESCHEDULE(vector))) - kstat_this_cpu.irqs[vector]++; + if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) { + smp_local_flush_tlb(); + kstat_this_cpu.irqs[vector]++; + } else if (unlikely(IS_RESCHEDULE(vector))) + kstat_this_cpu.irqs[vector]++; else { ia64_setreg(_IA64_REG_CR_TPR, vector); ia64_srlz_d(); @@ -227,8 +233,11 @@ void ia64_process_pending_intr(void) * Perform normal interrupt style processing */ while (vector != IA64_SPURIOUS_INT_VECTOR) { - if (unlikely(IS_RESCHEDULE(vector))) - kstat_this_cpu.irqs[vector]++; + if (unlikely(IS_LOCAL_TLB_FLUSH(vector))) { + smp_local_flush_tlb(); + kstat_this_cpu.irqs[vector]++; + } else if (unlikely(IS_RESCHEDULE(vector))) + kstat_this_cpu.irqs[vector]++; else { struct pt_regs *old_regs = set_irq_regs(NULL); @@ -260,12 +269,12 @@ void ia64_process_pending_intr(void) #ifdef CONFIG_SMP -extern irqreturn_t handle_IPI (int irq, void *dev_id); static irqreturn_t dummy_handler (int irq, void *dev_id) { BUG(); } +extern irqreturn_t handle_IPI (int irq, void *dev_id); static struct irqaction ipi_irqaction = { .handler = handle_IPI, @@ -278,6 +287,13 @@ static struct irqaction resched_irqaction = { .flags = IRQF_DISABLED, .name = "resched" }; + +static struct irqaction tlb_irqaction = { + .handler = dummy_handler, + .flags = SA_INTERRUPT, + .name = "tlb_flush" +}; + #endif void @@ -303,6 +319,7 @@ init_IRQ (void) #ifdef CONFIG_SMP register_percpu_irq(IA64_IPI_VECTOR, &ipi_irqaction); register_percpu_irq(IA64_IPI_RESCHEDULE, &resched_irqaction); + register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &tlb_irqaction); #endif #ifdef CONFIG_PERFMON pfm_init_percpu(); diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c index 55ddd80..221de38 100644 --- a/arch/ia64/kernel/smp.c +++ b/arch/ia64/kernel/smp.c @@ -50,6 +50,18 @@ #include /* + * Note: alignment of 4 entries/cacheline was empirically determined + * to be a good tradeoff between hot cachelines & spreading the array + * across too many cacheline. + */ +static struct local_tlb_flush_counts { + unsigned int count; +} __attribute__((__aligned__(32))) local_tlb_flush_counts[NR_CPUS]; + +static DEFINE_PER_CPU(unsigned int, shadow_flush_counts[NR_CPUS]) ____cacheline_aligned; + + +/* * Structure and data for smp_call_function(). This is designed to minimise static memory * requirements. It also looks cleaner. */ @@ -248,6 +260,62 @@ smp_send_reschedule (int cpu) platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0); } +/* + * Called with preeemption disabled. + */ +static void +smp_send_local_flush_tlb (int cpu) +{ + platform_send_ipi(cpu, IA64_IPI_LOCAL_TLB_FLUSH, IA64_IPI_DM_INT, 0); +} + +void +smp_local_flush_tlb(void) +{ + /* + * Use atomic ops. Otherwise, the load/increment/store sequence from + * a "++" operation can have the line stolen between the load & store. + * The overhead of the atomic op in negligible in this case & offers + * significant benefit for the brief periods where lots of cpus + * are simultaneously flushing TLBs. + */ + ia64_fetchadd(1, &local_tlb_flush_counts[smp_processor_id()].count, acq); + local_flush_tlb_all(); +} + +#define FLUSH_DELAY 5 /* Usec backoff to eliminate excessive cacheline bouncing */ + +void +smp_flush_tlb_cpumask(cpumask_t xcpumask) +{ + unsigned int *counts = __ia64_per_cpu_var(shadow_flush_counts); + cpumask_t cpumask = xcpumask; + int mycpu, cpu, flush_mycpu = 0; + + preempt_disable(); + mycpu = smp_processor_id(); + + for_each_cpu_mask(cpu, cpumask) + counts[cpu] = local_tlb_flush_counts[cpu].count; + + mb(); + for_each_cpu_mask(cpu, cpumask) { + if (cpu == mycpu) + flush_mycpu = 1; + else + smp_send_local_flush_tlb(cpu); + } + + if (flush_mycpu) + smp_local_flush_tlb(); + + for_each_cpu_mask(cpu, cpumask) + while(counts[cpu] == local_tlb_flush_counts[cpu].count) + udelay(FLUSH_DELAY); + + preempt_enable(); +} + void smp_flush_tlb_all (void) { diff --git a/arch/ia64/sn/kernel/sn2/sn2_smp.c b/arch/ia64/sn/kernel/sn2/sn2_smp.c index 601747b..5d318b5 100644 --- a/arch/ia64/sn/kernel/sn2/sn2_smp.c +++ b/arch/ia64/sn/kernel/sn2/sn2_smp.c @@ -46,6 +46,9 @@ DECLARE_PER_CPU(struct ptc_stats, ptcstats); static __cacheline_aligned DEFINE_SPINLOCK(sn2_global_ptc_lock); +/* 0 = old algorithm (no IPI flushes), 1 = ipi deadlock flush, 2 = ipi instead of SHUB ptc, >2 = always ipi */ +static int sn2_flush_opt = 0; + extern unsigned long sn2_ptc_deadlock_recovery_core(volatile unsigned long *, unsigned long, volatile unsigned long *, unsigned long, @@ -76,6 +79,8 @@ struct ptc_stats { unsigned long shub_itc_clocks; unsigned long shub_itc_clocks_max; unsigned long shub_ptc_flushes_not_my_mm; + unsigned long shub_ipi_flushes; + unsigned long shub_ipi_flushes_itc_clocks; }; #define sn2_ptctest 0 @@ -121,6 +126,18 @@ void sn_tlb_migrate_finish(struct mm_struct *mm) flush_tlb_mm(mm); } +static void +sn2_ipi_flush_all_tlb(struct mm_struct *mm) +{ + unsigned long itc; + + itc = ia64_get_itc(); + smp_flush_tlb_cpumask(mm->cpu_vm_mask); + itc = ia64_get_itc() - itc; + __get_cpu_var(ptcstats).shub_ipi_flushes_itc_clocks += itc; + __get_cpu_var(ptcstats).shub_ipi_flushes++; +} + /** * sn2_global_tlb_purge - globally purge translation cache of virtual address range * @mm: mm_struct containing virtual address range @@ -154,7 +171,12 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start, unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value, old_rr = 0; short nasids[MAX_NUMNODES], nix; nodemask_t nodes_flushed; - int active, max_active, deadlock; + int active, max_active, deadlock, flush_opt = sn2_flush_opt; + + if (flush_opt > 2) { + sn2_ipi_flush_all_tlb(mm); + return; + } nodes_clear(nodes_flushed); i = 0; @@ -189,6 +211,12 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start, return; } + if (flush_opt == 2) { + sn2_ipi_flush_all_tlb(mm); + preempt_enable(); + return; + } + itc = ia64_get_itc(); nix = 0; for_each_node_mask(cnode, nodes_flushed) @@ -256,6 +284,8 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start, } if (active >= max_active || i == (nix - 1)) { if ((deadlock = wait_piowc())) { + if (flush_opt == 1) + goto done; sn2_ptc_deadlock_recovery(nasids, ibegin, i, mynasid, ptc0, data0, ptc1, data1); if (reset_max_active_on_deadlock()) max_active = 1; @@ -267,6 +297,7 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start, start += (1UL << nbits); } while (start < end); +done: itc2 = ia64_get_itc() - itc2; __get_cpu_var(ptcstats).shub_itc_clocks += itc2; if (itc2 > __get_cpu_var(ptcstats).shub_itc_clocks_max) @@ -279,6 +310,11 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start, spin_unlock_irqrestore(PTC_LOCK(shub1), flags); + if (flush_opt == 1 && deadlock) { + __get_cpu_var(ptcstats).deadlocks++; + sn2_ipi_flush_all_tlb(mm); + } + preempt_enable(); } @@ -425,24 +461,42 @@ static int sn2_ptc_seq_show(struct seq_file *file, void *data) if (!cpu) { seq_printf(file, - "# cpu ptc_l newrid ptc_flushes nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max not_my_mm deadlock2\n"); - seq_printf(file, "# ptctest %d\n", sn2_ptctest); + "# cpu ptc_l newrid ptc_flushes nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max not_my_mm deadlock2 ipi_fluches ipi_nsec\n"); + seq_printf(file, "# ptctest %d, flushopt %d\n", sn2_ptctest, sn2_flush_opt); } if (cpu < NR_CPUS && cpu_online(cpu)) { stat = &per_cpu(ptcstats, cpu); - seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n", cpu, stat->ptc_l, + seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n", cpu, stat->ptc_l, stat->change_rid, stat->shub_ptc_flushes, stat->nodes_flushed, stat->deadlocks, 1000 * stat->lock_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec, 1000 * stat->shub_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec, 1000 * stat->shub_itc_clocks_max / per_cpu(cpu_info, cpu).cyc_per_usec, stat->shub_ptc_flushes_not_my_mm, - stat->deadlocks2); + stat->deadlocks2, + stat->shub_ipi_flushes, + 1000 * stat->shub_ipi_flushes_itc_clocks / per_cpu(cpu_info, cpu).cyc_per_usec); } return 0; } +static ssize_t sn2_ptc_proc_write(struct file *file, const char __user *user, size_t count, loff_t *data) +{ + int cpu; + char optstr[64]; + + if (copy_from_user(optstr, user, count)) + return -EFAULT; + optstr[count - 1] = '\0'; + sn2_flush_opt = simple_strtoul(optstr, NULL, 0); + + for_each_online_cpu(cpu) + memset(&per_cpu(ptcstats, cpu), 0, sizeof(struct ptc_stats)); + + return count; +} + static struct seq_operations sn2_ptc_seq_ops = { .start = sn2_ptc_seq_start, .next = sn2_ptc_seq_next, @@ -458,6 +512,7 @@ static int sn2_ptc_proc_open(struct inode *inode, struct file *file) static const struct file_operations proc_sn2_ptc_operations = { .open = sn2_ptc_proc_open, .read = seq_read, + .write = sn2_ptc_proc_write, .llseek = seq_lseek, .release = seq_release, }; diff --git a/include/asm-ia64/hw_irq.h b/include/asm-ia64/hw_irq.h index 27f9df6..c054d7a 100644 --- a/include/asm-ia64/hw_irq.h +++ b/include/asm-ia64/hw_irq.h @@ -66,6 +66,7 @@ extern int ia64_last_device_vector; #define IA64_PERFMON_VECTOR 0xee /* performanc monitor interrupt vector */ #define IA64_TIMER_VECTOR 0xef /* use highest-prio group 15 interrupt for timer */ #define IA64_MCA_WAKEUP_VECTOR 0xf0 /* MCA wakeup (must be >MCA_RENDEZ_VECTOR) */ +#define IA64_IPI_LOCAL_TLB_FLUSH 0xfc /* SMP flush local TLB */ #define IA64_IPI_RESCHEDULE 0xfd /* SMP reschedule */ #define IA64_IPI_VECTOR 0xfe /* inter-processor interrupt vector */ diff --git a/include/asm-ia64/tlbflush.h b/include/asm-ia64/tlbflush.h index cf9acb9..e37f9fb 100644 --- a/include/asm-ia64/tlbflush.h +++ b/include/asm-ia64/tlbflush.h @@ -27,9 +27,11 @@ extern void local_flush_tlb_all (void); #ifdef CONFIG_SMP extern void smp_flush_tlb_all (void); extern void smp_flush_tlb_mm (struct mm_struct *mm); + extern void smp_flush_tlb_cpumask (cpumask_t xcpumask); # define flush_tlb_all() smp_flush_tlb_all() #else # define flush_tlb_all() local_flush_tlb_all() +# define smp_flush_tlb_cpumask(m) local_flush_tlb_all() #endif static inline void @@ -94,6 +96,15 @@ flush_tlb_pgtables (struct mm_struct *mm, unsigned long start, unsigned long end */ } +/* + * Flush the local TLB. Invoked from another cpu using an IPI. + */ +#ifdef CONFIG_SMP +void smp_local_flush_tlb(void); +#else +#define smp_local_flush_tlb() +#endif + #define flush_tlb_kernel_range(start, end) flush_tlb_all() /* XXX fix me */ #endif /* _ASM_IA64_TLBFLUSH_H */ -- cgit v0.10.2