[PATCH V7 10/18] blk-throttle: choose a small throtl_slice for SSD
From: Shaohua Li
Date: Mon Mar 27 2017 - 13:55:43 EST
The throtl_slice is 100ms by default. This is a long time for SSD, a lot
of IO can run. To make cgroups have smoother throughput, we choose a
small value (20ms) for SSD.
Signed-off-by: Shaohua Li <shli@xxxxxx>
---
block/blk-sysfs.c | 2 ++
block/blk-throttle.c | 23 ++++++++++++++++++++---
block/blk.h | 2 ++
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index b315e62..7f090dd 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -906,6 +906,8 @@ int blk_register_queue(struct gendisk *disk)
blk_wb_init(q);
+ blk_throtl_register_queue(q);
+
if (q->request_fn || (q->mq_ops && q->elevator)) {
ret = elv_register_queue(q);
if (ret) {
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 93841da..d00c1c1 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -18,8 +18,9 @@ static int throtl_grp_quantum = 8;
/* Total max dispatch from all groups in one round */
static int throtl_quantum = 32;
-/* Throttling is performed over 100ms slice and after that slice is renewed */
-#define DFL_THROTL_SLICE (HZ / 10)
+/* Throttling is performed over a slice and after that slice is renewed */
+#define DFL_THROTL_SLICE_HD (HZ / 10)
+#define DFL_THROTL_SLICE_SSD (HZ / 50)
#define MAX_THROTL_SLICE (HZ)
static struct blkcg_policy blkcg_policy_throtl;
@@ -1961,7 +1962,6 @@ int blk_throtl_init(struct request_queue *q)
q->td = td;
td->queue = q;
- td->throtl_slice = DFL_THROTL_SLICE;
td->limit_valid[LIMIT_MAX] = true;
td->limit_index = LIMIT_MAX;
@@ -1982,6 +1982,23 @@ void blk_throtl_exit(struct request_queue *q)
kfree(q->td);
}
+void blk_throtl_register_queue(struct request_queue *q)
+{
+ struct throtl_data *td;
+
+ td = q->td;
+ BUG_ON(!td);
+
+ if (blk_queue_nonrot(q))
+ td->throtl_slice = DFL_THROTL_SLICE_SSD;
+ else
+ td->throtl_slice = DFL_THROTL_SLICE_HD;
+#ifndef CONFIG_BLK_DEV_THROTTLING_LOW
+ /* if no low limit, use previous default */
+ td->throtl_slice = DFL_THROTL_SLICE_HD;
+#endif
+}
+
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page)
{
diff --git a/block/blk.h b/block/blk.h
index bcd3de6..13070c3 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -319,10 +319,12 @@ static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
extern void blk_throtl_drain(struct request_queue *q);
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
+extern void blk_throtl_register_queue(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline void blk_throtl_drain(struct request_queue *q) { }
static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline void blk_throtl_exit(struct request_queue *q) { }
+static inline void blk_throtl_register_queue(struct request_queue *q) { }
#endif /* CONFIG_BLK_DEV_THROTTLING */
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
--
2.9.3