da(4): Short-circuit unnecessary BIO_FLUSH commands
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Authored by asomers on Nov 15 2017, 4:57 PM.

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Reviewers

scottl
imp

Commits

rS326779: MFC r326036:
rS326036: da(4): Short-circuit unnecessary BIO_FLUSH commands

Summary

da(4): Short-circuit unnecessary BIO_FLUSH commands

sys/cam/scsi/scsi_da.c
Complete BIO_FLUSH commands immediately if the da(4) device hasn't
been written since the last flush. If we haven't written to the
device, there is no reason to send a flush.

Submitted by: gibbs

Test Plan

ZFS test suite

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

asomers created this revision.Nov 15 2017, 4:57 PM

Herald added a subscriber: imp. · View Herald TranscriptNov 15 2017, 4:57 PM

Harbormaster completed remote builds in B12760: Diff 35285.Nov 15 2017, 4:57 PM

Same thing for the ata version?

Otherwise seems sane.

In D13106#272468, @imp wrote:

Same thing for the ata version?

Otherwise seems sane.

adastart is not totally symmetric with dastart. My naive attempt to port the change is causing deadlocks. Unless somebody else wants to try, I'm inclined to commit it just for da.

@imp, do you approve this revision?

As far as I can tell, this rev is fine. I get the ada issues and while I would like to see the same sort of thing done there, I accept that it's harder.

This revision is now accepted and ready to land.Nov 20 2017, 10:21 PM

Closed by commit rS326036: da(4): Short-circuit unnecessary BIO_FLUSH commands (authored by asomers). · Explain WhyNov 20 2017, 10:27 PM

This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

Path

Size

head/

sys/

cam/

scsi/

scsi_da.c

21 lines

Diff 35508

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head/sys/cam/scsi/scsi_da.c

da(4): Short-circuit unnecessary BIO_FLUSH commandsClosedPublicActions