[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>

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);
 }