Differential D22036

Reduce the scope of the object lock in fault.
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Authored by jeff on Oct 15 2019, 4:01 AM.

Details

Reviewers

kib
markj
alc

Commits

rS354156: Drop the object lock earlier in fault and don't relock it after pmap_enter().

Summary

This avoids reacquiring the object lock after fault is complete because we can now unbusy and pip wakeup without it.

It also releases the lock earlier in CoW and avoids an expensive copy while the object lock is held.

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Tests Not Applicable

Event Timeline

jeff created this revision.Oct 15 2019, 4:01 AM

Harbormaster completed remote builds in B27038: Diff 63284.Oct 15 2019, 4:02 AM

jeff edited the summary of this revision. (Show Details)Oct 15 2019, 4:07 AM

jeff added reviewers: kib, markj, alc.

I find the names fault_deallocate() and unlock_and_deallocate() confusing. I don't have a good alternative at the moment though.

sys/vm/vm_fault.c
193 ↗	(On Diff #63284)	Presumably this unlock can also be moved up?

This revision is now accepted and ready to land.Oct 15 2019, 2:42 PM

kib accepted this revision.Oct 16 2019, 12:38 PM

kib added inline comments.

sys/vm/vm_fault.c
185 ↗	(On Diff #63284)	I would suggest faultstate_deallocate.

Closed by commit rS354156: Drop the object lock earlier in fault and don't relock it after pmap_enter(). (authored by jeff). · Explain WhyOct 29 2019, 8:46 PM

This revision was automatically updated to reflect the committed changes.

jeff added a commit: rS354156: Drop the object lock earlier in fault and don't relock it after pmap_enter()..

Herald added a subscriber: imp. · View Herald TranscriptOct 29 2019, 8:46 PM

Revision Contents
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head/

sys/

vm/

vm_fault.c

17 lines

Diff 63764

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Reduce the scope of the object lock in fault.ClosedPublicActions