raid5: sysfs entry to control worker thread number
Add a sysfs entry to control running workqueue thread number. If
group_thread_cnt is set to 0, we will disable workqueue offload handling of
stripes.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 32fa113..d79ecd9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5145,10 +5145,70 @@
static struct md_sysfs_entry
raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
+static ssize_t
+raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf = mddev->private;
+ if (conf)
+ return sprintf(page, "%d\n", conf->worker_cnt_per_group);
+ else
+ return 0;
+}
+
+static int alloc_thread_groups(struct r5conf *conf, int cnt);
+static ssize_t
+raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
+{
+ struct r5conf *conf = mddev->private;
+ unsigned long new;
+ int err;
+ struct r5worker_group *old_groups;
+ int old_group_cnt;
+
+ if (len >= PAGE_SIZE)
+ return -EINVAL;
+ if (!conf)
+ return -ENODEV;
+
+ if (kstrtoul(page, 10, &new))
+ return -EINVAL;
+
+ if (new == conf->worker_cnt_per_group)
+ return len;
+
+ mddev_suspend(mddev);
+
+ old_groups = conf->worker_groups;
+ old_group_cnt = conf->worker_cnt_per_group;
+
+ conf->worker_groups = NULL;
+ err = alloc_thread_groups(conf, new);
+ if (err) {
+ conf->worker_groups = old_groups;
+ conf->worker_cnt_per_group = old_group_cnt;
+ } else {
+ if (old_groups)
+ kfree(old_groups[0].workers);
+ kfree(old_groups);
+ }
+
+ mddev_resume(mddev);
+
+ if (err)
+ return err;
+ return len;
+}
+
+static struct md_sysfs_entry
+raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
+ raid5_show_group_thread_cnt,
+ raid5_store_group_thread_cnt);
+
static struct attribute *raid5_attrs[] = {
&raid5_stripecache_size.attr,
&raid5_stripecache_active.attr,
&raid5_preread_bypass_threshold.attr,
+ &raid5_group_thread_cnt.attr,
NULL,
};
static struct attribute_group raid5_attrs_group = {