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Note when we tick.

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To help implement a policy of 'queue all trims until next I/O sched
tick' policy to help coalesce them, note when we tick so we can do
something special on the first call after the tick to get more work.

Sponsored by: Netflix
This commit is contained in:
Warner Losh 2018-02-22 05:43:50 +00:00
parent f2b9885036
commit c9878d6d63
1 changed files with 18 additions and 11 deletions
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29
sys/cam/cam_iosched.c
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@ -59,6 +59,19 @@ __FBSDID("$FreeBSD$");
static MALLOC_DEFINE(M_CAMSCHED, "CAM I/O Scheduler",
"CAM I/O Scheduler buffers");
/*
* Trim or similar currently pending completion. Should only be set for
* those drivers wishing only one Trim active at a time.
*/
#define CAM_IOSCHED_FLAG_TRIM_ACTIVE (1ul << 0)
/* Callout active, and needs to be torn down */
#define CAM_IOSCHED_FLAG_CALLOUT_ACTIVE (1ul << 1)
/* Timer has just ticked */
#define CAM_IOSCHED_FLAG_TICK (1ul << 2)
/* Periph drivers set these flags to indicate work */
#define CAM_IOSCHED_FLAG_WORK_FLAGS ((0xffffu) << 16)
/*
* Default I/O scheduler for FreeBSD. This implementation is just a thin-vineer
* over the bioq_* interface, with notions of separate calls for normal I/O and
@ -574,6 +587,7 @@ cam_iosched_ticker(void *arg)
cam_iosched_limiter_tick(&isc->write_stats);
cam_iosched_limiter_tick(&isc->trim_stats);
isc->flags |= CAM_IOSCHED_FLAGS_TICK;
cam_iosched_schedule(isc, isc->periph);
/*
@ -701,17 +715,6 @@ cam_iosched_cl_maybe_steer(struct control_loop *clp)
}
#endif
/*
* Trim or similar currently pending completion. Should only be set for
* those drivers wishing only one Trim active at a time.
*/
#define CAM_IOSCHED_FLAG_TRIM_ACTIVE (1ul << 0)
/* Callout active, and needs to be torn down */
#define CAM_IOSCHED_FLAG_CALLOUT_ACTIVE (1ul << 1)
/* Periph drivers set these flags to indicate work */
#define CAM_IOSCHED_FLAG_WORK_FLAGS ((0xffffu) << 16)
#ifdef CAM_IOSCHED_DYNAMIC
static void
cam_iosched_io_metric_update(struct cam_iosched_softc *isc,
@ -1322,6 +1325,10 @@ struct bio *
cam_iosched_next_bio(struct cam_iosched_softc *isc)
{
struct bio *bp;
bool wastick;
wastick = !!(isc->flags & CAM_IOSCHED_FLAGS_TICK);
isc->flags &= ~CAM_IOSCHED_FLAGS_TICK;
/*
* See if we have a trim that can be scheduled. We can only send one