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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.

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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.

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rS FreeBSD src repository
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Event Timeline

jeff created this revision.Oct 15 2019, 4:01 AM
jeff edited the summary of this revision. (Show Details)Oct 15 2019, 4:07 AM
jeff added reviewers: kib, markj, alc.
markj accepted this revision.Oct 15 2019, 2:42 PM

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.

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Mhead/sys/vm/vm_fault.c (17 lines)

Diff 63764

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head/sys/vm/vm_fault.c

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