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block: use ktime_get_ns() instead of sched_clock() for cfq and bfq

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cfq and bfq have some internal fields that use sched_clock() which can
trivially use ktime_get_ns() instead. Their timestamp fields in struct
request can also use ktime_get_ns(), which resolves the 8 year old
comment added by commit 28f4197e5d ("block: disable preemption before
using sched_clock()").

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 02:08:51 -07:00 • committed by Jens Axboe
parent 544ccc8dc9
commit 84c7afcebe
4 changed files with 57 additions and 63 deletions
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21
include/linux/blkdev.h
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@ -1799,42 +1799,33 @@ 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
/*
* This should not be using sched_clock(). A real patch is in progress
* to fix this up, until that is in place we need to disable preemption
* around sched_clock() in this function and set_io_start_time_ns().
*/
static inline void set_start_time_ns(struct request *req)
{
preempt_disable();
req->cgroup_start_time_ns = sched_clock();
preempt_enable();
req->cgroup_start_time_ns = ktime_get_ns();
}
static inline void set_io_start_time_ns(struct request *req)
{
preempt_disable();
req->cgroup_io_start_time_ns = sched_clock();
preempt_enable();
req->cgroup_io_start_time_ns = ktime_get_ns();
}
static inline uint64_t rq_start_time_ns(struct request *req)
static inline u64 rq_start_time_ns(struct request *req)
{
return req->cgroup_start_time_ns;
}
static inline uint64_t rq_io_start_time_ns(struct request *req)
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 uint64_t rq_start_time_ns(struct request *req)
static inline u64 rq_start_time_ns(struct request *req)
{
return 0;
}
static inline uint64_t rq_io_start_time_ns(struct request *req)
static inline u64 rq_io_start_time_ns(struct request *req)
{
return 0;
}