Handle most object reference count updates without object locks.
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Authored by jeff on Nov 20 2019, 12:32 AM.

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Reviewers

kib
markj
alc
dougm

Commits

rS355122: Use atomics in more cases for object references. We now can completely

Summary

This patch moves to only requiring the object lock on the last ref (or second to last for anonymous objects) as well as the first ref of a vnode object.

The object lock wouldn't be required for the first vnode ref except to serialize with vnode_pager_dealloc() which could race and drop a vref that is not yet acquired. I'm not sure if this is even possible anymore and if it is not vm_object_reference() could be simplified.

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Build Status

Buildable 27770
Build 25959: arc lint + arc unit

Event Timeline

jeff created this revision.Nov 20 2019, 12:32 AM

Harbormaster completed remote builds in B27650: Diff 64598.Nov 20 2019, 12:32 AM

jeff retitled this revision from Experimental object reference changes to Handle most object reference count updates without object locks..Nov 20 2019, 12:40 AM

jeff edited the summary of this revision. (Show Details)

jeff added reviewers: kib, markj, alc, dougm.

jeff set the repository for this revision to rS FreeBSD src repository - subversion.

Herald added a subscriber: imp. · View Herald TranscriptNov 20 2019, 12:40 AM

jeff added inline comments.Nov 20 2019, 12:42 AM