patch-2.4.21 linux-2.4.21/arch/alpha/kernel/smp.c

• Lines: 192
• Date: 2003-06-13 07:51:29.000000000 -0700
• Orig file: linux-2.4.20/arch/alpha/kernel/smp.c
• Orig date: 2002-08-02 17:39:42.000000000 -0700

diff -urN linux-2.4.20/arch/alpha/kernel/smp.c linux-2.4.21/arch/alpha/kernel/smp.c
@@ -77,11 +77,10 @@
 /* cpus reported in the hwrpb */
 static unsigned long hwrpb_cpu_present_mask __initdata = 0;
 
-static int max_cpus = -1;	/* Command-line limitation.  */
+static int max_cpus = NR_CPUS;	/* Command-line limitation.  */
 int smp_num_probed;		/* Internal processor count */
 int smp_num_cpus = 1;		/* Number that came online.  */
 int smp_threads_ready;		/* True once the per process idle is forked. */
-cycles_t cacheflush_time;
 
 int __cpu_number_map[NR_CPUS];
 int __cpu_logical_map[NR_CPUS];
@@ -104,7 +103,7 @@
 	return 1;
 }
 
-__setup("maxcpus", maxcpus);
+__setup("maxcpus=", maxcpus);
 
 
 /*
@@ -175,6 +174,9 @@
 	/* Get our local ticker going. */
 	smp_setup_percpu_timer(cpuid);
 
+	/* Call platform-specific callin, if specified */
+	if (alpha_mv.smp_callin) alpha_mv.smp_callin();
+
 	/* Must have completely accurate bogos.  */
 	__sti();
 
@@ -184,20 +186,20 @@
 	 */
 	wait_boot_cpu_to_stop(cpuid);
 	mb();
- try_again:
+
 	calibrate_delay();
 
 	smp_store_cpu_info(cpuid);
 
 	{
 #define LPJ(c) ((long)cpu_data[c].loops_per_jiffy)
-	  static int tries = 3;
 	  long diff = LPJ(boot_cpuid) - LPJ(cpuid);
 	  if (diff < 0) diff = -diff;
 				
-	  if (diff > LPJ(boot_cpuid)/10 && --tries) {
-	    printk("Bogus BogoMIPS for cpu %d - retrying...\n", cpuid);
-	    goto try_again;
+	  if (diff > LPJ(boot_cpuid)/10) {
+	  	printk("Bogus BogoMIPS for cpu %d - trusting boot CPU\n",
+		       cpuid);
+		loops_per_jiffy = LPJ(cpuid) = LPJ(boot_cpuid);
 	  }
 	}
 
@@ -225,64 +227,6 @@
 	cpu_idle();
 }
 
-
-/*
- * Rough estimation for SMP scheduling, this is the number of cycles it
- * takes for a fully memory-limited process to flush the SMP-local cache.
- *
- * We are not told how much cache there is, so we have to guess.
- */
-static void __init
-smp_tune_scheduling (int cpuid)
-{
-	struct percpu_struct *cpu;
-	unsigned long on_chip_cache;
-	unsigned long freq;
-
-	cpu = (struct percpu_struct*)((char*)hwrpb + hwrpb->processor_offset
-				      + cpuid * hwrpb->processor_size);
-	switch (cpu->type)
-	{
-	case EV45_CPU:
-		on_chip_cache = 16 + 16;
-		break;
-
-	case EV5_CPU:
-	case EV56_CPU:
-		on_chip_cache = 8 + 8 + 96;
-		break;
-
-	case PCA56_CPU:
-		on_chip_cache = 16 + 8;
-		break;
-
-	case EV6_CPU:
-	case EV67_CPU:
-		on_chip_cache = 64 + 64;
-		break;
-
-	default:
-		on_chip_cache = 8 + 8;
-		break;
-	}
-
-	freq = hwrpb->cycle_freq ? : est_cycle_freq;
-
-#if 0
-	/* Magic estimation stolen from x86 port.  */
-	cacheflush_time = freq / 1024L * on_chip_cache / 5000L;
-
-        printk("Using heuristic of %d cycles.\n",
-               cacheflush_time);
-#else
-	/* Magic value to force potential preemption of other CPUs.  */
-	cacheflush_time = INT_MAX;
-
-        printk("Using heuristic of %d cycles.\n",
-               cacheflush_time);
-#endif
-}
-
 /*
  * Send a message to a secondary's console.  "START" is one such
  * interesting message.  ;-)
@@ -622,7 +566,6 @@
 	current->processor = boot_cpuid;
 
 	smp_store_cpu_info(boot_cpuid);
-	smp_tune_scheduling(boot_cpuid);
 	smp_setup_percpu_timer(boot_cpuid);
 
 	init_idle();
@@ -641,6 +584,9 @@
 
 	cpu_count = 1;
 	for (i = 0; i < NR_CPUS; i++) {
+		if (cpu_count >= max_cpus)
+			break;
+
 		if (i == boot_cpuid)
 			continue;
 
@@ -666,8 +612,8 @@
 	}
 	printk(KERN_INFO "SMP: Total of %d processors activated "
 	       "(%lu.%02lu BogoMIPS).\n",
-	       cpu_count, (bogosum + 2500) / (500000/HZ),
-	       ((bogosum + 2500) / (5000/HZ)) % 100);
+	       cpu_count, bogosum / (500000/HZ),
+	       (bogosum / (5000/HZ)) % 100);
 
 	smp_num_cpus = cpu_count;
 }
@@ -922,11 +868,36 @@
 	       && time_before (jiffies, timeout))
 		barrier();
 
-	/* We either got one or timed out -- clear the lock.  */
+	/* If there's no response yet, log a message but allow a longer
+	 * timeout period -- if we get a response this time, log
+	 * a message saying when we got it.. 
+	 */
+	if (atomic_read(&data.unstarted_count) > 0) {
+		long start_time = jiffies;
+		printk(KERN_ERR "%s: initial timeout -- trying long wait\n",
+		       __FUNCTION__);
+		timeout = jiffies + 30 * HZ;
+		while (atomic_read(&data.unstarted_count) > 0
+		       && time_before(jiffies, timeout))
+			barrier();
+		if (atomic_read(&data.unstarted_count) <= 0) {
+			long delta = jiffies - start_time;
+			printk(KERN_ERR 
+			       "%s: response %ld.%ld seconds into long wait\n",
+			       __FUNCTION__, delta / HZ,
+			       (100 * (delta - ((delta / HZ) * HZ))) / HZ);
+		}
+	}
+
+	/* We either got one or timed out -- clear the lock. */
 	mb();
 	smp_call_function_data = 0;
-	if (atomic_read (&data.unstarted_count) > 0)
-		return -ETIMEDOUT;
+
+	/* 
+	 * If after both the initial and long timeout periods we still don't
+	 * have a response, something is very wrong...
+	 */
+	BUG_ON(atomic_read (&data.unstarted_count) > 0);
 
 	/* Wait for a complete response, if needed.  */
 	if (wait) {