From: Zhaoyang Huang <[email protected]>
The 'over-sized' bio under blk throttle control will be delayed to
launch which breaks original IO timing and have the immediate BW be
not within the bps limit. Introduce a helper function to calculate block
device's budgt which provide the allowed bytes for current bio.
Signed-off-by: Zhaoyang Huang <[email protected]>
---
block/blk-throttle.c | 44 ++++++++++++++++++++++++++++++++++++++
include/linux/blk-cgroup.h | 10 +++++++++
2 files changed, 54 insertions(+)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index f4850a6f860b..41c75258183d 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -10,6 +10,7 @@
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/blktrace_api.h>
+#include <linux/cgroup.h>
#include "blk.h"
#include "blk-cgroup-rwstat.h"
#include "blk-stat.h"
@@ -2365,6 +2366,49 @@ void blk_throtl_bio_endio(struct bio *bio)
}
#endif
+unsigned long blk_throttle_budgt(struct block_device *bdev)
+{
+ struct request_queue *q = bdev_get_queue(bdev);
+ struct blkcg *blkcg;
+ struct blkcg_gq *blkg;
+ struct throtl_grp *tg;
+ long long bytes_allowed = 0;
+ unsigned long jiffy_elapsed, jiffy_elapsed_rnd;
+ u64 bps_limit;
+
+ if (!q)
+ return U64_MAX;
+
+ rcu_read_lock();
+ spin_lock_irq(&q->queue_lock);
+ blkcg = css_to_blkcg(task_css(current, io_cgrp_id));
+ if (!blkcg)
+ goto out;
+
+ blkg = blkg_lookup(blkcg, q);
+ if (!blkg || !blkg_tryget(blkg))
+ goto out;
+
+ tg = blkg_to_tg(blkg);
+ bps_limit = tg_bps_limit(tg, READ);
+ if (bps_limit == U64_MAX)
+ goto out;
+
+ jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[READ];
+ if (!jiffy_elapsed)
+ jiffy_elapsed_rnd = tg->td->throtl_slice;
+
+ jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice);
+ bytes_allowed = calculate_bytes_allowed(bps_limit, jiffy_elapsed_rnd) +
+ tg->carryover_bytes[READ];
+ blkg_put(blkg);
+out:
+ spin_unlock_irq(&q->queue_lock);
+ rcu_read_unlock();
+ return bytes_allowed;
+}
+
+
int blk_throtl_init(struct gendisk *disk)
{
struct request_queue *q = disk->queue;
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index dd5841a42c33..ba79fa464e0a 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -15,10 +15,12 @@
*/
#include <linux/types.h>
+#include <linux/limits.h>
struct bio;
struct cgroup_subsys_state;
struct gendisk;
+struct block_device;
#define FC_APPID_LEN 129
@@ -45,6 +47,14 @@ static inline struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)
}
#endif /* CONFIG_BLK_CGROUP */
+#ifdef CONFIG_BLK_DEV_THROTTLING
+unsigned long blk_throttle_budgt(struct block_device *bdev);
+#else
+static inline unsigned long blk_throttle_budgt(struct block_device *bdev)
+{
+ return U64_MAX;
+}
+#endif
int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len);
char *blkcg_get_fc_appid(struct bio *bio);
--
2.25.1