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block: consolidate struct request timestamp fields

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Currently, struct request has four timestamp fields:

- A start time, set at get_request time, in jiffies, used for iostats
- An I/O start time, set at start_request time, in ktime nanoseconds,
  used for blk-stats (i.e., wbt, kyber, hybrid polling)
- Another start time and another I/O start time, used for cfq and bfq

These can all be consolidated into one start time and one I/O start
time, both in ktime nanoseconds, shaving off up to 16 bytes from struct
request depending on the kernel config.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Omar Sandoval
2018-05-09 02:08:53 -07:00
committed by Jens Axboe
parent 4bc6339a58
commit 522a777566
10 changed files with 30 additions and 76 deletions
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38
include/linux/blkdev.h
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@@ -205,7 +205,8 @@ struct request {
struct gendisk *rq_disk;
struct hd_struct *part;
unsigned long start_time;
/* Time that I/O was submitted to the kernel. */
u64 start_time_ns;
/* Time that I/O was submitted to the device. */
u64 io_start_time_ns;
@@ -277,8 +278,6 @@ struct request {
#ifdef CONFIG_BLK_CGROUP
struct request_list *rl; /* rl this rq is alloced from */
unsigned long long cgroup_start_time_ns;
unsigned long long cgroup_io_start_time_ns; /* when passed to hardware */
#endif
};
@@ -1798,39 +1797,6 @@ int kblockd_schedule_work(struct work_struct *work);
int kblockd_schedule_work_on(int cpu, struct work_struct *work);
int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
#ifdef CONFIG_BLK_CGROUP
static inline void set_start_time_ns(struct request *req)
{
req->cgroup_start_time_ns = ktime_get_ns();
}
static inline void set_io_start_time_ns(struct request *req)
{
req->cgroup_io_start_time_ns = ktime_get_ns();
}
static inline u64 rq_start_time_ns(struct request *req)
{
return req->cgroup_start_time_ns;
}
static inline u64 rq_io_start_time_ns(struct request *req)
{
return req->cgroup_io_start_time_ns;
}
#else
static inline void set_start_time_ns(struct request *req) {}
static inline void set_io_start_time_ns(struct request *req) {}
static inline u64 rq_start_time_ns(struct request *req)
{
return 0;
}
static inline u64 rq_io_start_time_ns(struct request *req)
{
return 0;
}
#endif
#define MODULE_ALIAS_BLOCKDEV(major,minor) \
MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \