kernel-ark/arch/ia64/sn/kernel/sn2/sn2_smp.c
Dean Roe c1902aae32 [IA64] - Avoid slow TLB purges on SGI Altix systems
flush_tlb_all() can be a scaling issue on large SGI Altix systems
since it uses the global call_lock and always executes on all cpus.
When a process enters flush_tlb_range() to purge TLBs for another
process, it is possible to avoid flush_tlb_all() and instead allow
sn2_global_tlb_purge() to purge TLBs only where necessary.

This patch modifies flush_tlb_range() so that this case can be handled
by platform TLB purge functions and updates ia64_global_tlb_purge()
accordingly.  sn2_global_tlb_purge() now calculates the region register
value from the mm argument introduced with this patch.

Signed-off-by: Dean Roe <roe@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-10-27 14:44:58 -07:00

513 lines
13 KiB
C

/*
* SN2 Platform specific SMP Support
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2000-2005 Silicon Graphics, Inc. All rights reserved.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/nodemask.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/sal.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/tlb.h>
#include <asm/numa.h>
#include <asm/hw_irq.h>
#include <asm/current.h>
#include <asm/sn/sn_cpuid.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/addrs.h>
#include <asm/sn/shub_mmr.h>
#include <asm/sn/nodepda.h>
#include <asm/sn/rw_mmr.h>
DEFINE_PER_CPU(struct ptc_stats, ptcstats);
DECLARE_PER_CPU(struct ptc_stats, ptcstats);
static __cacheline_aligned DEFINE_SPINLOCK(sn2_global_ptc_lock);
void sn2_ptc_deadlock_recovery(short *, short, int, volatile unsigned long *, unsigned long data0,
volatile unsigned long *, unsigned long data1);
#ifdef DEBUG_PTC
/*
* ptctest:
*
* xyz - 3 digit hex number:
* x - Force PTC purges to use shub:
* 0 - no force
* 1 - force
* y - interupt enable
* 0 - disable interrupts
* 1 - leave interuupts enabled
* z - type of lock:
* 0 - global lock
* 1 - node local lock
* 2 - no lock
*
* Note: on shub1, only ptctest == 0 is supported. Don't try other values!
*/
static unsigned int sn2_ptctest = 0;
static int __init ptc_test(char *str)
{
get_option(&str, &sn2_ptctest);
return 1;
}
__setup("ptctest=", ptc_test);
static inline int ptc_lock(unsigned long *flagp)
{
unsigned long opt = sn2_ptctest & 255;
switch (opt) {
case 0x00:
spin_lock_irqsave(&sn2_global_ptc_lock, *flagp);
break;
case 0x01:
spin_lock_irqsave(&sn_nodepda->ptc_lock, *flagp);
break;
case 0x02:
local_irq_save(*flagp);
break;
case 0x10:
spin_lock(&sn2_global_ptc_lock);
break;
case 0x11:
spin_lock(&sn_nodepda->ptc_lock);
break;
case 0x12:
break;
default:
BUG();
}
return opt;
}
static inline void ptc_unlock(unsigned long flags, int opt)
{
switch (opt) {
case 0x00:
spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
break;
case 0x01:
spin_unlock_irqrestore(&sn_nodepda->ptc_lock, flags);
break;
case 0x02:
local_irq_restore(flags);
break;
case 0x10:
spin_unlock(&sn2_global_ptc_lock);
break;
case 0x11:
spin_unlock(&sn_nodepda->ptc_lock);
break;
case 0x12:
break;
default:
BUG();
}
}
#else
#define sn2_ptctest 0
static inline int ptc_lock(unsigned long *flagp)
{
spin_lock_irqsave(&sn2_global_ptc_lock, *flagp);
return 0;
}
static inline void ptc_unlock(unsigned long flags, int opt)
{
spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
}
#endif
struct ptc_stats {
unsigned long ptc_l;
unsigned long change_rid;
unsigned long shub_ptc_flushes;
unsigned long nodes_flushed;
unsigned long deadlocks;
unsigned long lock_itc_clocks;
unsigned long shub_itc_clocks;
unsigned long shub_itc_clocks_max;
};
static inline unsigned long wait_piowc(void)
{
volatile unsigned long *piows, zeroval;
unsigned long ws;
piows = pda->pio_write_status_addr;
zeroval = pda->pio_write_status_val;
do {
cpu_relax();
} while (((ws = *piows) & SH_PIO_WRITE_STATUS_PENDING_WRITE_COUNT_MASK) != zeroval);
return ws;
}
void sn_tlb_migrate_finish(struct mm_struct *mm)
{
if (mm == current->mm)
flush_tlb_mm(mm);
}
/**
* sn2_global_tlb_purge - globally purge translation cache of virtual address range
* @mm: mm_struct containing virtual address range
* @start: start of virtual address range
* @end: end of virtual address range
* @nbits: specifies number of bytes to purge per instruction (num = 1<<(nbits & 0xfc))
*
* Purges the translation caches of all processors of the given virtual address
* range.
*
* Note:
* - cpu_vm_mask is a bit mask that indicates which cpus have loaded the context.
* - cpu_vm_mask is converted into a nodemask of the nodes containing the
* cpus in cpu_vm_mask.
* - if only one bit is set in cpu_vm_mask & it is the current cpu & the
* process is purging its own virtual address range, then only the
* local TLB needs to be flushed. This flushing can be done using
* ptc.l. This is the common case & avoids the global spinlock.
* - if multiple cpus have loaded the context, then flushing has to be
* done with ptc.g/MMRs under protection of the global ptc_lock.
*/
void
sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
unsigned long end, unsigned long nbits)
{
int i, opt, shub1, cnode, mynasid, cpu, lcpu = 0, nasid, flushed = 0;
int mymm = (mm == current->active_mm);
volatile unsigned long *ptc0, *ptc1;
unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value;
short nasids[MAX_NUMNODES], nix;
nodemask_t nodes_flushed;
nodes_clear(nodes_flushed);
i = 0;
for_each_cpu_mask(cpu, mm->cpu_vm_mask) {
cnode = cpu_to_node(cpu);
node_set(cnode, nodes_flushed);
lcpu = cpu;
i++;
}
if (i == 0)
return;
preempt_disable();
if (likely(i == 1 && lcpu == smp_processor_id() && mymm)) {
do {
ia64_ptcl(start, nbits << 2);
start += (1UL << nbits);
} while (start < end);
ia64_srlz_i();
__get_cpu_var(ptcstats).ptc_l++;
preempt_enable();
return;
}
if (atomic_read(&mm->mm_users) == 1 && mymm) {
flush_tlb_mm(mm);
__get_cpu_var(ptcstats).change_rid++;
preempt_enable();
return;
}
itc = ia64_get_itc();
nix = 0;
for_each_node_mask(cnode, nodes_flushed)
nasids[nix++] = cnodeid_to_nasid(cnode);
rr_value = (mm->context << 3) | REGION_NUMBER(start);
shub1 = is_shub1();
if (shub1) {
data0 = (1UL << SH1_PTC_0_A_SHFT) |
(nbits << SH1_PTC_0_PS_SHFT) |
(rr_value << SH1_PTC_0_RID_SHFT) |
(1UL << SH1_PTC_0_START_SHFT);
ptc0 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH1_PTC_0);
ptc1 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH1_PTC_1);
} else {
data0 = (1UL << SH2_PTC_A_SHFT) |
(nbits << SH2_PTC_PS_SHFT) |
(1UL << SH2_PTC_START_SHFT);
ptc0 = (long *)GLOBAL_MMR_PHYS_ADDR(0, SH2_PTC +
(rr_value << SH2_PTC_RID_SHFT));
ptc1 = NULL;
}
mynasid = get_nasid();
itc = ia64_get_itc();
opt = ptc_lock(&flags);
itc2 = ia64_get_itc();
__get_cpu_var(ptcstats).lock_itc_clocks += itc2 - itc;
__get_cpu_var(ptcstats).shub_ptc_flushes++;
__get_cpu_var(ptcstats).nodes_flushed += nix;
do {
if (shub1)
data1 = start | (1UL << SH1_PTC_1_START_SHFT);
else
data0 = (data0 & ~SH2_PTC_ADDR_MASK) | (start & SH2_PTC_ADDR_MASK);
for (i = 0; i < nix; i++) {
nasid = nasids[i];
if ((!(sn2_ptctest & 3)) && unlikely(nasid == mynasid && mymm)) {
ia64_ptcga(start, nbits << 2);
ia64_srlz_i();
} else {
ptc0 = CHANGE_NASID(nasid, ptc0);
if (ptc1)
ptc1 = CHANGE_NASID(nasid, ptc1);
pio_atomic_phys_write_mmrs(ptc0, data0, ptc1,
data1);
flushed = 1;
}
}
if (flushed
&& (wait_piowc() &
(SH_PIO_WRITE_STATUS_WRITE_DEADLOCK_MASK))) {
sn2_ptc_deadlock_recovery(nasids, nix, mynasid, ptc0, data0, ptc1, data1);
}
start += (1UL << nbits);
} while (start < end);
itc2 = ia64_get_itc() - itc2;
__get_cpu_var(ptcstats).shub_itc_clocks += itc2;
if (itc2 > __get_cpu_var(ptcstats).shub_itc_clocks_max)
__get_cpu_var(ptcstats).shub_itc_clocks_max = itc2;
ptc_unlock(flags, opt);
preempt_enable();
}
/*
* sn2_ptc_deadlock_recovery
*
* Recover from PTC deadlocks conditions. Recovery requires stepping thru each
* TLB flush transaction. The recovery sequence is somewhat tricky & is
* coded in assembly language.
*/
void sn2_ptc_deadlock_recovery(short *nasids, short nix, int mynasid, volatile unsigned long *ptc0, unsigned long data0,
volatile unsigned long *ptc1, unsigned long data1)
{
extern void sn2_ptc_deadlock_recovery_core(volatile unsigned long *, unsigned long,
volatile unsigned long *, unsigned long, volatile unsigned long *, unsigned long);
short nasid, i;
unsigned long *piows, zeroval;
__get_cpu_var(ptcstats).deadlocks++;
piows = (unsigned long *) pda->pio_write_status_addr;
zeroval = pda->pio_write_status_val;
for (i=0; i < nix; i++) {
nasid = nasids[i];
if (!(sn2_ptctest & 3) && nasid == mynasid)
continue;
ptc0 = CHANGE_NASID(nasid, ptc0);
if (ptc1)
ptc1 = CHANGE_NASID(nasid, ptc1);
sn2_ptc_deadlock_recovery_core(ptc0, data0, ptc1, data1, piows, zeroval);
}
}
/**
* sn_send_IPI_phys - send an IPI to a Nasid and slice
* @nasid: nasid to receive the interrupt (may be outside partition)
* @physid: physical cpuid to receive the interrupt.
* @vector: command to send
* @delivery_mode: delivery mechanism
*
* Sends an IPI (interprocessor interrupt) to the processor specified by
* @physid
*
* @delivery_mode can be one of the following
*
* %IA64_IPI_DM_INT - pend an interrupt
* %IA64_IPI_DM_PMI - pend a PMI
* %IA64_IPI_DM_NMI - pend an NMI
* %IA64_IPI_DM_INIT - pend an INIT interrupt
*/
void sn_send_IPI_phys(int nasid, long physid, int vector, int delivery_mode)
{
long val;
unsigned long flags = 0;
volatile long *p;
p = (long *)GLOBAL_MMR_PHYS_ADDR(nasid, SH_IPI_INT);
val = (1UL << SH_IPI_INT_SEND_SHFT) |
(physid << SH_IPI_INT_PID_SHFT) |
((long)delivery_mode << SH_IPI_INT_TYPE_SHFT) |
((long)vector << SH_IPI_INT_IDX_SHFT) |
(0x000feeUL << SH_IPI_INT_BASE_SHFT);
mb();
if (enable_shub_wars_1_1()) {
spin_lock_irqsave(&sn2_global_ptc_lock, flags);
}
pio_phys_write_mmr(p, val);
if (enable_shub_wars_1_1()) {
wait_piowc();
spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
}
}
EXPORT_SYMBOL(sn_send_IPI_phys);
/**
* sn2_send_IPI - send an IPI to a processor
* @cpuid: target of the IPI
* @vector: command to send
* @delivery_mode: delivery mechanism
* @redirect: redirect the IPI?
*
* Sends an IPI (InterProcessor Interrupt) to the processor specified by
* @cpuid. @vector specifies the command to send, while @delivery_mode can
* be one of the following
*
* %IA64_IPI_DM_INT - pend an interrupt
* %IA64_IPI_DM_PMI - pend a PMI
* %IA64_IPI_DM_NMI - pend an NMI
* %IA64_IPI_DM_INIT - pend an INIT interrupt
*/
void sn2_send_IPI(int cpuid, int vector, int delivery_mode, int redirect)
{
long physid;
int nasid;
physid = cpu_physical_id(cpuid);
nasid = cpuid_to_nasid(cpuid);
/* the following is used only when starting cpus at boot time */
if (unlikely(nasid == -1))
ia64_sn_get_sapic_info(physid, &nasid, NULL, NULL);
sn_send_IPI_phys(nasid, physid, vector, delivery_mode);
}
#ifdef CONFIG_PROC_FS
#define PTC_BASENAME "sgi_sn/ptc_statistics"
static void *sn2_ptc_seq_start(struct seq_file *file, loff_t * offset)
{
if (*offset < NR_CPUS)
return offset;
return NULL;
}
static void *sn2_ptc_seq_next(struct seq_file *file, void *data, loff_t * offset)
{
(*offset)++;
if (*offset < NR_CPUS)
return offset;
return NULL;
}
static void sn2_ptc_seq_stop(struct seq_file *file, void *data)
{
}
static int sn2_ptc_seq_show(struct seq_file *file, void *data)
{
struct ptc_stats *stat;
int cpu;
cpu = *(loff_t *) data;
if (!cpu) {
seq_printf(file, "# ptc_l change_rid shub_ptc_flushes shub_nodes_flushed deadlocks lock_nsec shub_nsec shub_nsec_max\n");
seq_printf(file, "# ptctest %d\n", sn2_ptctest);
}
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\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);
}
return 0;
}
static struct seq_operations sn2_ptc_seq_ops = {
.start = sn2_ptc_seq_start,
.next = sn2_ptc_seq_next,
.stop = sn2_ptc_seq_stop,
.show = sn2_ptc_seq_show
};
int sn2_ptc_proc_open(struct inode *inode, struct file *file)
{
return seq_open(file, &sn2_ptc_seq_ops);
}
static struct file_operations proc_sn2_ptc_operations = {
.open = sn2_ptc_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static struct proc_dir_entry *proc_sn2_ptc;
static int __init sn2_ptc_init(void)
{
if (!(proc_sn2_ptc = create_proc_entry(PTC_BASENAME, 0444, NULL))) {
printk(KERN_ERR "unable to create %s proc entry", PTC_BASENAME);
return -EINVAL;
}
proc_sn2_ptc->proc_fops = &proc_sn2_ptc_operations;
spin_lock_init(&sn2_global_ptc_lock);
return 0;
}
static void __exit sn2_ptc_exit(void)
{
remove_proc_entry(PTC_BASENAME, NULL);
}
module_init(sn2_ptc_init);
module_exit(sn2_ptc_exit);
#endif /* CONFIG_PROC_FS */