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Differential D22821

Don't relock the vm object after busy sleeps.
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Authored by jeff on Dec 15 2019, 2:53 AM.
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alc
kib
markj
dougm
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rS356059: Don't unnecessarily relock the vm object after sleeps. This results in a
Summary

A surprising amount of contention comes from waking up after busy sleep, locking the object, and then dropping immediately.

This change also makes it cleaner to sleep with an object read lock in some cases as well as avoiding touching the object after sleep which closes one of the type stability issues.

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rS FreeBSD src repository - subversion
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Event Timeline

jeff created this revision.Dec 15 2019, 2:53 AM
Harbormaster completed remote builds in B28159: Diff 65675.Dec 15 2019, 2:53 AM
jeff edited the summary of this revision. (Show Details)Dec 15 2019, 2:57 AM
jeff added reviewers: alc, doug_freebsd.con.com, kib, markj.
jeff set the repository for this revision to rS FreeBSD src repository - subversion.
Herald added a subscriber: imp. · View Herald TranscriptDec 15 2019, 2:57 AM
jeff edited reviewers, added: dougm; removed: doug_freebsd.con.com.Dec 15 2019, 2:57 AM
kib accepted this revision.Dec 15 2019, 7:55 PM
This revision is now accepted and ready to land.Dec 15 2019, 7:55 PM
markj accepted this revision.Dec 16 2019, 8:39 PM
markj added inline comments.
sys/vm/vm_page.c
1057 ↗(On Diff #65675)

It looks strange to me to compare a bool with 0. if (!_vm_page_busy_sleep(...)) would make more sense IMO.

jeff updated this revision to Diff 65898.Dec 21 2019, 7:42 PM

Comment a little better. Use bool appropriately.

This revision now requires review to proceed.Dec 21 2019, 7:42 PM
Harbormaster completed remote builds in B28282: Diff 65898.Dec 21 2019, 7:42 PM
kib accepted this revision.Dec 21 2019, 9:31 PM
This revision is now accepted and ready to land.Dec 21 2019, 9:31 PM
Closed by commit rS356059: Don't unnecessarily relock the vm object after sleeps. This results in a (authored by jeff). · Explain WhyDec 24 2019, 6:38 PM
This revision was automatically updated to reflect the committed changes.
jeff added a commit: rS356059: Don't unnecessarily relock the vm object after sleeps. This results in a.

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Changeset List

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head/
sys/
vm/
5 lines
37 lines

Diff 65962

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head/sys/vm/vm_fault.c

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head/sys/vm/vm_page.c

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