[IA64-SGI] Update TLB flushing code for SN platform

This patch finishes support for SHUB2 (the new chipset). Most of the
changes are performance related. A few changes are workarounds for
"interesting" chipset features.

Some temporary debugging code has also been deleted.

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

1 files changed, 75 insertions, 121 deletions

diff --git a/arch/ia64/sn/kernel/sn2/sn2_smp.c b/arch/ia64/sn/kernel/sn2/sn2_smp.c
index 471bbaa65d1b..f153a4c35c70 100644
--- a/arch/ia64/sn/kernel/sn2/sn2_smp.c
+++ b/arch/ia64/sn/kernel/sn2/sn2_smp.c
@@ -5,7 +5,7 @@
  * 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.
+ * Copyright (C) 2000-2006 Silicon Graphics, Inc. All rights reserved.
  */
 
 #include <linux/init.h>
@@ -46,104 +46,28 @@ 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);
+void sn2_ptc_deadlock_recovery(short *, short, short, int, volatile unsigned long *, unsigned long,
+        volatile unsigned long *, unsigned long);
 
-#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!
+ * Note: some is the following is captured here to make degugging easier
+ * (the macros make more sense if you see the debug patch - not posted)
  */
-
-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
+#define local_node_uses_ptc_ga(sh1)     ((sh1) ? 1 : 0)
+#define max_active_pio(sh1)             ((sh1) ? 32 : 7)
+#define reset_max_active_on_deadlock()  1
+#define PTC_LOCK(sh1)                   ((sh1) ? &sn2_global_ptc_lock : &sn_nodepda->ptc_lock)
 
-static inline int ptc_lock(unsigned long *flagp)
+static inline void ptc_lock(int sh1, unsigned long *flagp)
 {
-        spin_lock_irqsave(&sn2_global_ptc_lock, *flagp);
-        return 0;
+        spin_lock_irqsave(PTC_LOCK(sh1), *flagp);
 }
 
-static inline void ptc_unlock(unsigned long flags, int opt)
+static inline void ptc_unlock(int sh1, unsigned long flags)
 {
-        spin_unlock_irqrestore(&sn2_global_ptc_lock, flags);
+        spin_unlock_irqrestore(PTC_LOCK(sh1), flags);
 }
-#endif
 
 struct ptc_stats {
         unsigned long ptc_l;
@@ -151,27 +75,30 @@ struct ptc_stats {
         unsigned long shub_ptc_flushes;
         unsigned long nodes_flushed;
         unsigned long deadlocks;
+        unsigned long deadlocks2;
         unsigned long lock_itc_clocks;
         unsigned long shub_itc_clocks;
         unsigned long shub_itc_clocks_max;
+        unsigned long shub_ptc_flushes_not_my_mm;
 };
 
 static inline unsigned long wait_piowc(void)
 {
-        volatile unsigned long *piows, zeroval;
-        unsigned long ws;
+        volatile unsigned long *piows;
+        unsigned long zeroval, 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;
+        return (ws & SH_PIO_WRITE_STATUS_WRITE_DEADLOCK_MASK) != 0;
 }
 
 void sn_tlb_migrate_finish(struct mm_struct *mm)
 {
-        if (mm == current->mm)
+        /* flush_tlb_mm is inefficient if more than 1 users of mm */
+        if (mm == current->mm && mm && atomic_read(&mm->mm_users) == 1)
                 flush_tlb_mm(mm);
 }
 
@@ -201,12 +128,14 @@ 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 && current->mm);
+        int i, ibegin, shub1, cnode, mynasid, cpu, lcpu = 0, nasid;
+        int mymm = (mm == current->active_mm && mm == current->mm);
+        int use_cpu_ptcga;
         volatile unsigned long *ptc0, *ptc1;
-        unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value;
+        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;
 
         nodes_clear(nodes_flushed);
         i = 0;
@@ -267,41 +196,56 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
         
 
         mynasid = get_nasid();
+        use_cpu_ptcga = local_node_uses_ptc_ga(shub1);
+        max_active = max_active_pio(shub1);
 
         itc = ia64_get_itc();
-        opt = ptc_lock(&flags);
+        ptc_lock(shub1, &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;
+        if (!mymm)
+                 __get_cpu_var(ptcstats).shub_ptc_flushes_not_my_mm++;
 
+        if (use_cpu_ptcga && !mymm) {
+                old_rr = ia64_get_rr(start);
+                ia64_set_rr(start, (old_rr & 0xff) | (rr_value << 8));
+                ia64_srlz_d();
+        }
+
+        wait_piowc();
         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++) {
+                deadlock = 0;
+                active = 0;
+                for (ibegin = 0, i = 0; i < nix; i++) {
                         nasid = nasids[i];
-                        if ((!(sn2_ptctest & 3)) && unlikely(nasid == mynasid && mymm)) {
+                        if (use_cpu_ptcga && unlikely(nasid == mynasid)) {
                                 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;
+                                pio_atomic_phys_write_mmrs(ptc0, data0, ptc1, data1);
+                                active++;
+                        }
+                        if (active >= max_active || i == (nix - 1)) {
+                                if ((deadlock = wait_piowc())) {
+                                        sn2_ptc_deadlock_recovery(nasids, ibegin, i, mynasid, ptc0, data0, ptc1, data1);
+                                        if (reset_max_active_on_deadlock())
+                                                max_active = 1;
+                                }
+                                active = 0;
+                                ibegin = i + 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;
@@ -309,7 +253,12 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
         if (itc2 > __get_cpu_var(ptcstats).shub_itc_clocks_max)
                 __get_cpu_var(ptcstats).shub_itc_clocks_max = itc2;
 
-        ptc_unlock(flags, opt);
+        if (old_rr) {
+                ia64_set_rr(start, old_rr);
+                ia64_srlz_d();
+        }
+
+        ptc_unlock(shub1, flags);
 
         preempt_enable();
 }
@@ -321,27 +270,30 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
  * 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,
+void sn2_ptc_deadlock_recovery(short *nasids, short ib, short ie, 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,
+        extern unsigned long 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;
+        unsigned long *piows, zeroval, n;
 
         __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++) {
+
+        for (i=ib; i <= ie; i++) {
                 nasid = nasids[i];
-                if (!(sn2_ptctest & 3) && nasid == mynasid)
+                if (local_node_uses_ptc_ga(is_shub1()) && 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);
+
+                n = sn2_ptc_deadlock_recovery_core(ptc0, data0, ptc1, data1, piows, zeroval);
+                __get_cpu_var(ptcstats).deadlocks2 += n;
         }
 
 }
@@ -452,20 +404,22 @@ static int sn2_ptc_seq_show(struct seq_file *file, void *data)
         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,
+                           "# 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);
         }
 
         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,
+                seq_printf(file, "cpu %d %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);
+                                1000 * stat->shub_itc_clocks_max / per_cpu(cpu_info, cpu).cyc_per_usec,
+                                stat->shub_ptc_flushes_not_my_mm,
+                                stat->deadlocks2);
         }
-
         return 0;
 }
 
@@ -476,7 +430,7 @@ static struct seq_operations sn2_ptc_seq_ops = {
         .show = sn2_ptc_seq_show
 };
 
-int sn2_ptc_proc_open(struct inode *inode, struct file *file)
+static int sn2_ptc_proc_open(struct inode *inode, struct file *file)
 {
         return seq_open(file, &sn2_ptc_seq_ops);
 }