[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 <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 60 insertions, 5 deletions

diff --git a/arch/ia64/sn/kernel/sn2/sn2_smp.c b/arch/ia64/sn/kernel/sn2/sn2_smp.c
index 601747b1e22a..5d318b579fb1 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,
 };