From fd24d8f30012a02f7d107174bb460eb641d8cbce Mon Sep 17 00:00:00 2001
From: Neil Horman <nhorman@tuxdriver.com>
Date: Thu, 9 Aug 2012 14:18:23 -0400
Subject: [PATCH] Improve rescan ability for newly allocated interrupts

When an interrupt is registered after irqbalance starts we just add it as a misc
interrupt, even if its something that we want to balance.  Instead, lets add the
irq to a temp list, force a rescan, then make sure the newly discovered irqs get
added properly on the rescan.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
---
 classify.c       | 33 ++++++++++++++++++++++++++++++---
 irqbalance.h     |  2 +-
 procinterrupts.c | 14 ++++----------
 3 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/classify.c b/classify.c
index 3c76cea..1ae4ff9 100644
--- a/classify.c
+++ b/classify.c
@@ -52,6 +52,7 @@ static short class_codes[MAX_CLASS] = {
 };
 
 static GList *interrupts_db;
+static GList *new_irq_list;
 static GList *banned_irqs;
 
 #define SYSDEV_DIR "/sys/bus/pci/devices"
@@ -326,6 +327,8 @@ void rebuild_irq_db(void)
 {
 	DIR *devdir = opendir(SYSDEV_DIR);
 	struct dirent *entry;
+	GList *gentry;
+	struct irq_info *ninfo, *iinfo;
 
 	free_irq_db();
 		
@@ -341,22 +344,46 @@ void rebuild_irq_db(void)
 	build_one_dev_entry(entry->d_name);
 
 	} while (entry != NULL);
+
 	closedir(devdir);
+
+	if (!new_irq_list)
+		return;
+	gentry = g_list_first(new_irq_list);	
+	while(gentry) {
+		ninfo = gentry->data;
+		iinfo = get_irq_info(ninfo->irq);
+		new_irq_list = g_list_remove(gentry, ninfo);
+		if (!iinfo) {
+			if (debug_mode)
+				printf("Adding untracked IRQ %d to database\n", ninfo->irq);
+			interrupts_db = g_list_append(interrupts_db, ninfo);
+		} else 
+			free(ninfo);
+
+		gentry = g_list_first(new_irq_list);
+	}
+	g_list_free(new_irq_list);
+	new_irq_list = NULL;
+		
 }
 
-struct irq_info *add_misc_irq(int irq)
+struct irq_info *add_new_irq(int irq)
 {
-	struct irq_info *new;
+	struct irq_info *new, *nnew;
 
 	new = calloc(sizeof(struct irq_info), 1);
-	if (!new)
+	nnew = calloc(sizeof(struct irq_info), 1);
+	if (!new || !nnew)
 		return NULL;
 
 	new->irq = irq;
 	new->type = IRQ_TYPE_LEGACY;
 	new->class = IRQ_OTHER;
 	new->numa_node = get_numa_node(-1);
+	memcpy(nnew, new, sizeof(struct irq_info));
 	interrupts_db = g_list_append(interrupts_db, new);
+	new_irq_list = g_list_append(new_irq_list, nnew);
 	return new;
 }
 
diff --git a/irqbalance.h b/irqbalance.h
index 636a69e..e46f31f 100644
--- a/irqbalance.h
+++ b/irqbalance.h
@@ -108,7 +108,7 @@ extern void add_banned_irq(int irq);
 extern void for_each_irq(GList *list, void (*cb)(struct irq_info *info,  void *data), void *data);
 extern struct irq_info *get_irq_info(int irq);
 extern void migrate_irq(GList **from, GList **to, struct irq_info *info);
-extern struct irq_info *add_misc_irq(int irq);
+extern struct irq_info *add_new_irq(int irq);
 #define irq_numa_node(irq) ((irq)->numa_node)
 
 
diff --git a/procinterrupts.c b/procinterrupts.c
index f1d6745..431fffa 100644
--- a/procinterrupts.c
+++ b/procinterrupts.c
@@ -84,16 +84,10 @@ void parse_proc_interrupts(void)
 		number = strtoul(line, NULL, 10);
 		info = get_irq_info(number);
 		if (!info) {
-			/*
- 			 * If this is our 0th pass through this routine
- 			 * this is an irq that wasn't reported in sysfs
- 			 * and we should just add it.  If we've been running
- 			 * a while then this irq just appeared and its time  
- 			 * to rescan our irqs
- 			 */
-			if (cycle_count)
-				need_rescan = 1;
-			info = add_misc_irq(number);
+			if (!cycle_count)
+				continue;
+			need_rescan = 1;
+			info = add_new_irq(number);
 		}
 
 		count = 0;