Attributes that use vmstat can now use attr->value2 to specify an optional
accuracy. Based on the provided value, we will setup appropriate vmstat
thresholds.
Signed-off-by: Anton Vorontsov <anton.voront...@linaro.org>
---
include/linux/vmevent.h | 5 +++++
mm/vmevent.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 61 insertions(+)
diff --git a/include/linux/vmevent.h b/include/linux/vmevent.h
index b1c4016..b8c1394 100644
--- a/include/linux/vmevent.h
+++ b/include/linux/vmevent.h
@@ -46,6 +46,11 @@ struct vmevent_attr {
__u64 value;
/*
+ * Some attributes accept two configuration values.
+ */
+ __u64 value2;
+
+ /*
* Type of profiled attribute from VMEVENT_ATTR_XXX
*/
__u32 type;
diff --git a/mm/vmevent.c b/mm/vmevent.c
index 8c0fbe6..8113bda 100644
--- a/mm/vmevent.c
+++ b/mm/vmevent.c
@@ -28,8 +28,13 @@ struct vmevent_watch {
/* poll */
wait_queue_head_t waitq;
+
+ struct list_head node;
};
+static LIST_HEAD(vmevent_watchers);
+static DEFINE_SPINLOCK(vmevent_watchers_lock);
+
typedef u64 (*vmevent_attr_sample_fn)(struct vmevent_watch *watch,
struct vmevent_attr *attr);
@@ -259,12 +264,57 @@ out:
return ret;
}
+#ifdef CONFIG_SMP
+
+static void vmevent_set_thresholds(void)
+{
+ struct vmevent_watch *w;
+ struct zone *zone;
+ u64 thres = ULLONG_MAX;
+
+ spin_lock(&vmevent_watchers_lock);
+
+ list_for_each_entry(w, &vmevent_watchers, node) {
+ int i;
+
+ for (i = 0; i < w->config.counter; i++) {
+ struct vmevent_attr *attr = &w->config.attrs[i];
+
+ if (attr->type != VMEVENT_ATTR_NR_FREE_PAGES)
+ continue;
+ if (!attr->value2)
+ continue;
+ thres = min(thres, attr->value2);
+ }
+ }
+
+ if (thres == ULLONG_MAX)
+ thres = 0;
+
+ thres = (thres + PAGE_SIZE - 1) / PAGE_SIZE;
+
+ for_each_populated_zone(zone)
+ set_zone_stat_thresholds(zone, NULL, thres);
+
+ spin_unlock(&vmevent_watchers_lock);
+}
+
+#else
+static inline void vmevent_set_thresholds(void) {}
+#endif /* CONFIG_SMP */
+
static int vmevent_release(struct inode *inode, struct file *file)
{
struct vmevent_watch *watch = file->private_data;
cancel_delayed_work_sync(&watch->work);
+ spin_lock(&vmevent_watchers_lock);
+ list_del(&watch->node);
+ spin_unlock(&vmevent_watchers_lock);
+
+ vmevent_set_thresholds();
+
kfree(watch);
return 0;
@@ -328,6 +378,10 @@ static int vmevent_setup_watch(struct vmevent_watch *watch)
watch->sample_attrs = attrs;
watch->nr_attrs = nr;
+ spin_lock(&vmevent_watchers_lock);
+ list_add(&watch->node, &vmevent_watchers);
+ spin_unlock(&vmevent_watchers_lock);
+
return 0;
}
@@ -363,6 +417,8 @@ SYSCALL_DEFINE1(vmevent_fd,
if (err)
goto err_free;
+ vmevent_set_thresholds();
+
fd = get_unused_fd_flags(O_RDONLY);
if (fd < 0) {
err = fd;
--
1.7.12.1
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