From e44eed4faef6ee1bd1ae41dd27a8513d37681f7f Mon Sep 17 00:00:00 2001
From: liuchao <liuchao173@huawei.com>
Date: Tue, 17 Dec 2019 02:54:57 +0000
Subject: [PATCH] add switch to clear affinity hint

All irqs' affinity hints are cleared in update_affinity_hint and forced
to rebalance. In some scenarios, it will affect performance.
---
 hint_verify.c | 26 +++++++++++++++++++++++++-
 irqbalance.c  | 10 ++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/hint_verify.c b/hint_verify.c
index 0718078..11ef868 100644
--- a/hint_verify.c
+++ b/hint_verify.c
@@ -16,6 +16,7 @@ extern int keep_going;
 extern GMainLoop *main_loop;
 extern gboolean scan();
 extern int last_interval;
+extern int clear_affinity_hint;
 
 int real_sleep_interval;
 int sleep_interval_count;
@@ -57,7 +58,8 @@ void update_affinity_hint(struct irq_info *info, void *data __attribute__((unuse
 	if (!hint_enabled)
 		return;
 
-	cpus_clear(info->affinity_hint);
+	if (clear_affinity_hint)
+		cpus_clear(info->affinity_hint);
 	sprintf(path, "/proc/irq/%d/affinity_hint", info->irq);
 	file = fopen(path, "r");
 	if (!file)
@@ -80,6 +82,27 @@ void update_affinity_hint(struct irq_info *info, void *data __attribute__((unuse
 		free(line);
 }
 
+static void check_clear()
+{
+	char *line = NULL;
+	size_t size = 0;
+	FILE *file;
+
+	file = fopen("/etc/sysconfig/irqbalance_clear", "r");
+	if (!file)
+		return;
+	if (getline(&line, &size, file) <= 0)
+		goto out;
+	if (line != NULL && strstr(line, "0") != NULL)
+		clear_affinity_hint = 0;
+	else
+		clear_affinity_hint = 1;
+
+out:
+	fclose(file);
+	free(line);
+}
+
 /*
  * This function is the main loop of irqbalance, which include:
  * 1. scan opration for irq balancing;
@@ -104,6 +127,7 @@ gboolean poll_hint_affinity_and_scan(gpointer data __attribute__((unused)))
 	sleep_count++;
 
 	if (need_verify_flag && hint_changed()) {
+		check_clear();
 		for_each_irq(NULL, update_affinity_hint, NULL);
 		if (hint_has_changed) {
 			hint_has_changed = FALSE;
diff --git a/irqbalance.c b/irqbalance.c
index 05eaa29..77076fa 100644
--- a/irqbalance.c
+++ b/irqbalance.c
@@ -55,6 +55,7 @@ int foreground_mode;
 int numa_avail;
 int journal_logging = 0;
 int need_rescan;
+int clear_affinity_hint = 1;
 unsigned int log_mask = TO_ALL;
 const char *log_indent;
 unsigned long power_thresh = ULONG_MAX;
@@ -104,15 +105,16 @@ struct option lopts[] = {
 	{"loadlimit", 1, NULL, 'g'},
 	{"rulesconfig", 1, NULL, 'r'},
 	{"verifyhint", 1, NULL, 'v'},
+	{"notclearhint", 0, NULL, 'n'},
 	{0, 0, 0, 0}
 };
 
 static void usage(void)
 {
	log(TO_CONSOLE, LOG_INFO, "irqbalance [--oneshot | -o] [--debug | -d] [--foreground | -f] [--journal | -j] [--hintpolicy | -h <subset>]\n");
 	log(TO_CONSOLE, LOG_INFO, "	[--powerthresh= | -p <off> | <n>] [--banirq= | -i <n>] [--banmod= | -m <module>] [--policyscript= | -l <script>]\n");
 	log(TO_CONSOLE, LOG_INFO, "	[--pid= | -s <file>] [--deepestcache= | -c <n>] [--interval= | -t <n>] [--migrateval= | -e <n>] [--loadlimit= | -g <n>]\n");
-	log(TO_CONSOLE, LOG_INFO, "	[--rulesconfig= | -r <config>] [--verifyhint= | -v n]\n");
+	log(TO_CONSOLE, LOG_INFO, "	[--rulesconfig= | -r <config>] [--verifyhint= | -v n] [--notclearhint | -n]\n");
 }
 
 static void version(void)
@@ -126,7 +128,7 @@ static void parse_command_line(int argc, char **argv)
 	unsigned long val;
 
 	while ((opt = getopt_long(argc, argv,
-		"odfjVi:p:s:c:b:l:m:t:e:g:r:h:v:",
+		"odfjVni:p:s:c:b:l:m:t:e:g:r:h:v:",
 		lopts, &longind)) != -1) {
 
 		switch(opt) {
@@ -225,6 +227,9 @@ static void parse_command_line(int argc, char **argv)
 			case 'r':
 				rules_config_file = strdup(optarg);
 				break;
+			case 'n':
+				clear_affinity_hint = 0;
+				break;
 		}
 	}
 }
-- 
2.19.1