ufs: try to elide the interlock in ufs_itimes
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Authored by mjg on Sep 10 2022, 9:33 PM.

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kib
mckusick

Commits

rG60457d1ea068: ufs: try to elide the interlock in ufs_itimes
rGca63cbbe9554: ufs: always call ufs_itimes on close
rG04f095a49165: ufs: try to elide the interlock in ufs_itimes
rGbe931de6c99f: ufs: always call ufs_itimes on close

Summary

Especially if the fs is mounted noatime none of the flags tend to be set.

While here dedup code with ufsfifo_close.

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rG FreeBSD src repository

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mjg requested review of this revision.Sep 10 2022, 9:33 PM

mjg created this revision.

Then why checking for v_usecount > 1 at all? It can go to 1 at any time.

I'm guessing the original code was avoiding the call, expecting for it to happen in ufs_inactive later. This retains the ultimately racy nature, except avoids the interlock.

I agree, it probably was an attempt for micro-optimization, I do not see any other reason. Then, since inactivation is not guaranteed to occur now, while close is, I think the check for v_usecount should be removed.

mjg updated this revision to Diff 110485.Sep 12 2022, 11:29 PM

mjg retitled this revision from ufs: do a lockless usecount check in ufs_close to ufs: try to elide the interlock in ufs_itimes.

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

kib accepted this revision.Sep 13 2022, 10:17 AM

This revision is now accepted and ready to land.Sep 13 2022, 10:17 AM

With updates, looks good.

Closed by commit rGbe931de6c99f: ufs: always call ufs_itimes on close (authored by mjg). · Explain WhySep 14 2022, 6:13 PM

This revision was automatically updated to reflect the committed changes.

mjg added a commit: rGbe931de6c99f: ufs: always call ufs_itimes on close.

Herald added a subscriber: imp. · View Herald TranscriptSep 14 2022, 6:13 PM

mjg added a commit: rG04f095a49165: ufs: try to elide the interlock in ufs_itimes.Sep 14 2022, 6:13 PM

mjg added a commit: rGca63cbbe9554: ufs: always call ufs_itimes on close.Aug 24 2023, 11:25 PM