Irqbalance checks sysfs interface instead of kernel command line
for isolated and adaptive-ticks CPUS. These CPUs are banned by
default. This behavior can be overriden by using IRQBALANCE_BANNED_CPUS
enviroment variable.
Signed-off-by: Petr Holasek <pholasek at redhat.com>
---
cputree.c | 57 +++++++++++++++++++++++++++++++++------------------------
1 file changed, 33 insertions(+), 24 deletions(-)
diff --git a/cputree.c b/cputree.c
index 5a2b69d..a188ead 100644
--- a/cputree.c
+++ b/cputree.c
@@ -59,17 +59,21 @@ cpumask_t cpu_possible_map;
cpumask_t unbanned_cpus;
/*
- * By default do not place IRQs on CPUs the kernel keeps isolated,
- * as specified through the isolcpus= boot commandline. Users can
+ * By default do not place IRQs on CPUs the kernel keeps isolated or
+ * nohz_full, as specified through the boot commandline. Users can
* override this with the IRQBALANCE_BANNED_CPUS environment variable.
*/
static void setup_banned_cpus(void)
{
FILE *file;
- char *c, *line = NULL;
+ char *line = NULL;
size_t size = 0;
- const char *isolcpus = "isolcpus=";
char buffer[4096];
+ cpumask_t nohz_full;
+ cpumask_t isolated_cpus;
+
+ cpus_clear(isolated_cpus);
+ cpus_clear(nohz_full);
/* A manually specified cpumask overrides auto-detection. */
if (getenv("IRQBALANCE_BANNED_CPUS")) {
@@ -77,30 +81,35 @@ static void setup_banned_cpus(void)
goto out;
}
- file = fopen("/proc/cmdline", "r");
- if (!file)
- goto out;
-
- if (getline(&line, &size, file) <= 0)
- goto out2;
-
- if ((c = strstr(line, isolcpus))) {
- char *end;
- int len;
-
- c += strlen(isolcpus);
- for (end = c; *end != ' ' && *end != '\0' && *end != '\n'; end++);
- len = end - c;
+ file = fopen("/sys/devices/system/cpu/isolated", "r");
+ if (file) {
+ if (getline(&line, &size, file) > 0) {
+ cpulist_parse(line, size, isolated_cpus);
+ free(line);
+ line = NULL;
+ size = 0;
+ }
+ fclose(file);
+ }
- cpulist_parse(c, len, banned_cpus);
+ file = fopen("/sys/devices/system/cpu/nohz_full", "r");
+ if (file) {
+ if (getline(&line, &size, file) > 0) {
+ cpulist_parse(line, size, nohz_full);
+ free(line);
+ line = NULL;
+ size = 0;
+ }
+ fclose(file);
}
- out2:
- fclose(file);
- out:
- cpumask_scnprintf(buffer, 4096, banned_cpus);
+ cpus_or(banned_cpus, nohz_full, isolated_cpus);
+
+out:
+ cpumask_scnprintf(buffer, 4096, isolated_cpus);
log(TO_CONSOLE, LOG_INFO, "Isolated CPUs: %s\n", buffer);
- free(line);
+ cpumask_scnprintf(buffer, 4096, nohz_full);
+ log(TO_CONSOLE, LOG_INFO, "Adaptive-ticks CPUs: %s\n", buffer);
}
static struct topo_obj* add_cache_domain_to_package(struct topo_obj *cache,
--
2.4.3
