Author: imp
Date: Fri Sep 15 20:16:06 2017
New Revision: 323625
URL: https://svnweb.freebsd.org/changeset/base/323625
Log:
Allow multiple TRIMs to be done for nda
Don't call cam_iosched_trim_done or cam_iosched_submit_trim for nda
since its hardware can handle almost an arbitrary number of TRIMs and
we don't have to be careful to only ever do one.
Sponsored by: Netflix
Modified:
head/sys/cam/nvme/nvme_da.c
Modified: head/sys/cam/nvme/nvme_da.c
==============================================================================
--- head/sys/cam/nvme/nvme_da.c Fri Sep 15 20:15:55 2017 (r323624)
+++ head/sys/cam/nvme/nvme_da.c Fri Sep 15 20:16:06 2017 (r323625)
@@ -920,7 +920,12 @@ ndastart(struct cam_periph *periph, union ccb *start_c
nda_nvme_trim(softc, &start_ccb->nvmeio, dsm_range, 1);
start_ccb->ccb_h.ccb_state = NDA_CCB_TRIM;
start_ccb->ccb_h.flags |= CAM_UNLOCKED;
- cam_iosched_submit_trim(softc->cam_iosched); /* XXX
*/
+ /*
+ * Note: We can have multiple TRIMs in flight, so we
don't call
+ * cam_iosched_submit_trim(softc->cam_iosched);
+ * since that forces the I/O scheduler to only schedule
one at a time.
+ * On NVMe drives, this is a performance disaster.
+ */
goto out;
}
case BIO_FLUSH:
@@ -1013,7 +1018,11 @@ ndadone(struct cam_periph *periph, union ccb *done_ccb
TAILQ_INIT(&queue);
TAILQ_CONCAT(&queue, &softc->trim_req.bps, bio_queue);
#endif
- cam_iosched_trim_done(softc->cam_iosched);
+ /*
+ * Since we can have multiple trims in flight, we don't
+ * need to call this here.
+ * cam_iosched_trim_done(softc->cam_iosched);
+ */
ndaschedule(periph);
cam_periph_unlock(periph);
#ifdef notyet
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