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blk-throttle: choose a small throtl_slice for SSD

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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@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Shaohua Li 2017-03-27 10:51:38 -07:00 committed by Jens Axboe
parent 297e3d8547
commit d61fcfa4bb
3 changed files with 24 additions and 3 deletions
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2
block/blk-sysfs.c
View File

@ -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) {

23
block/blk-throttle.c
View File

@ -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)
{

2
block/blk.h
View File

@ -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);