Patch 11/23 - Bitmaps, Cpumasks and Nodemasks

[Paul Jackson]

P11.cpumask_sparc_simplify - Simplify some sparc64 cpumask loop code
        Make use of for_each_cpu_mask() macro to simplify and optimize
        a couple of sparc64 per-CPU loops.  This code change has _not_
        been tested or reviewed.  Feedback welcome.  There is non-trivial
        risk that I still don't understand the logic here.

Index: 2.6.5.bitmap/arch/sparc64/kernel/smp.c
===================================================================
--- 2.6.5.bitmap.orig/arch/sparc64/kernel/smp.c	2004-04-05 02:41:32.000000000 -0700
+++ 2.6.5.bitmap/arch/sparc64/kernel/smp.c	2004-04-08 04:18:02.000000000 -0700
@@ -406,14 +406,8 @@
 	int i;
 
 	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
-	for (i = 0; i < NR_CPUS; i++) {
-		if (cpu_isset(i, mask)) {
-			spitfire_xcall_helper(data0, data1, data2, pstate, i);
-			cpu_clear(i, mask);
-			if (cpus_empty(mask))
-				break;
-		}
-	}
+	for_each_cpu_mask(i, mask)
+		spitfire_xcall_helper(data0, data1, data2, pstate, i);
 }
 
 /* Cheetah now allows to send the whole 64-bytes of data in the interrupt
@@ -456,25 +450,19 @@
 
 	nack_busy_id = 0;
 	{
-		cpumask_t work_mask = mask;
 		int i;
 
-		for (i = 0; i < NR_CPUS; i++) {
-			if (cpu_isset(i, work_mask)) {
-				u64 target = (i << 14) | 0x70;
-
-				if (!is_jalapeno)
-					target |= (nack_busy_id << 24);
-				__asm__ __volatile__(
-					"stxa	%%g0, [%0] %1\n\t"
-					"membar	#Sync\n\t"
-					: /* no outputs */
-					: "r" (target), "i" (ASI_INTR_W));
-				nack_busy_id++;
- 				cpu_clear(i, work_mask);
-				if (cpus_empty(work_mask))
-					break;
-			}
+		for_each_cpu_mask(i, mask) {
+			u64 target = (i << 14) | 0x70;
+
+			if (!is_jalapeno)
+				target |= (nack_busy_id << 24);
+			__asm__ __volatile__(
+				"stxa	%%g0, [%0] %1\n\t"
+				"membar	#Sync\n\t"
+				: /* no outputs */
+				: "r" (target), "i" (ASI_INTR_W));
+			nack_busy_id++;
 		}
 	}
 
@@ -507,7 +495,6 @@
 			printk("CPU[%d]: mondo stuckage result[%016lx]\n",
 			       smp_processor_id(), dispatch_stat);
 		} else {
-			cpumask_t work_mask = mask;
 			int i, this_busy_nack = 0;
 
 			/* Delay some random time with interrupts enabled
@@ -518,22 +505,17 @@
 			/* Clear out the mask bits for cpus which did not
 			 * NACK us.
 			 */
-			for (i = 0; i < NR_CPUS; i++) {
-				if (cpu_isset(i, work_mask)) {
-					u64 check_mask;
-
-					if (is_jalapeno)
-						check_mask = (0x2UL << (2*i));
-					else
-						check_mask = (0x2UL <<
-							      this_busy_nack);
-					if ((dispatch_stat & check_mask) == 0)
-						cpu_clear(i, mask);
-					this_busy_nack += 2;
-					cpu_clear(i, work_mask);
-					if (cpus_empty(work_mask))
-						break;
-				}
+			for_each_cpu_mask(i, mask) {
+				u64 check_mask;
+
+				if (is_jalapeno)
+					check_mask = (0x2UL << (2*i));
+				else
+					check_mask = (0x2UL <<
+						      this_busy_nack);
+				if ((dispatch_stat & check_mask) == 0)
+					cpu_clear(i, mask);
+				this_busy_nack += 2;
 			}
 
 			goto retry;


-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@xxxxxxx> 1.650.933.1373
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