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Differential D7192

Implement mtx_trylock_spin(9).
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Authored by kib on Jul 12 2016, 3:23 AM.
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rS303211: Implement mtx_trylock_spin(9).

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rS FreeBSD src repository - subversion
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kib updated this revision to Diff 18306.Jul 12 2016, 3:23 AM
kib retitled this revision from to Implement mtx_trylock_spin(9)..
kib updated this object.
kib edited the test plan for this revision. (Show Details)
kib added a reviewer: jhb.
kib set the repository for this revision to rS FreeBSD src repository - subversion.
Herald added a subscriber: imp. · View Herald TranscriptJul 12 2016, 3:23 AM
jhb added inline comments.Jul 15 2016, 8:39 PM
sys/kern/kern_mutex.c
296 ↗(On Diff #18306)

Please use 'mtx_trylock_spin' in these kassert messages.

306 ↗(On Diff #18306)

Try-lock operations don't generally invoke checkorder since they can't block (so can't deadlock). They also don't define new orders either.

kib updated this revision to Diff 18479.Jul 15 2016, 9:29 PM
kib marked 2 inline comments as done.

Remove CHECKORDER call.
Change function names in the kassert messages.
Fix UP compilation.

kib updated this revision to Diff 18492.Jul 17 2016, 2:53 AM

Bde requests:
add comment into mutex.h
change assert for recursion.

jhb accepted this revision.Jul 18 2016, 12:49 PM
jhb edited edge metadata.

Implementation looks fine. I missed earlier though that mutex.9 should be updated as well.

This revision is now accepted and ready to land.Jul 18 2016, 12:49 PM
kib added a comment.Jul 18 2016, 1:44 PM
In D7192#150431, @jhb wrote:

Implementation looks fine. I missed earlier though that mutex.9 should be updated as well.

Sure, I waited until the code changes are accepted.

kib updated this revision to Diff 18507.Jul 18 2016, 1:45 PM
kib edited edge metadata.

Document mtx_trylock_spin(9).

This revision now requires review to proceed.Jul 18 2016, 1:45 PM
Herald added a reviewer: manpages. · View Herald TranscriptJul 18 2016, 1:45 PM
kib updated this revision to Diff 18508.Jul 18 2016, 1:48 PM
kib edited edge metadata.

Install symlink.

Herald edited edge metadata. · View Herald TranscriptJul 18 2016, 1:48 PM
jhb accepted this revision.Jul 18 2016, 2:34 PM
jhb edited edge metadata.
jhb added inline comments.
share/man/man9/mutex.9
44 ↗(On Diff #18508)

Also mtx_trylock_spin_flags?

This revision is now accepted and ready to land.Jul 18 2016, 2:34 PM
kib added inline comments.Jul 18 2016, 3:04 PM
share/man/man9/mutex.9
44 ↗(On Diff #18508)

MTX_RECURSE is not supported, and MTX_QUIT is useless.

I did not mentioned mtx_trylock_spin_flags() because I do not see how it could be useful. Its presence is just an implementation detail (cannot avoid defining it without breaking all ten layers of macros).

I will add that if you consider that important.

jhb added inline comments.Jul 18 2016, 5:11 PM
share/man/man9/mutex.9
44 ↗(On Diff #18508)

Ok. The only one I thought could be useful would be MTX_QUIET since it does use LOCK_LOG_TRY.

kib updated this revision to Diff 18535.Jul 19 2016, 6:02 AM
kib edited edge metadata.

Document mtx_trlock_spin_flags.

Mention mtx_trylock* in the description of MTX_RECURSE flag.

This revision now requires review to proceed.Jul 19 2016, 6:02 AM
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jhb accepted this revision.Jul 22 2016, 8:59 PM
jhb edited edge metadata.
jhb added inline comments.
share/man/man9/mutex.9
468 ↗(On Diff #18535)

Perhaps "support recursion; that is, attempting to acquire an already-owned mutex fails."

This does seem to be a bit of an odd bit of the API (perhaps its my fault or perhaps we inherited it from BSD/OS?)

This revision is now accepted and ready to land.Jul 22 2016, 8:59 PM
kib added inline comments.Jul 23 2016, 5:29 AM
share/man/man9/mutex.9
468 ↗(On Diff #18535)

It can be changed to support recursion, but all uses of trylock must be audited. I think it is not critical in any way.

Closed by commit rS303211: Implement mtx_trylock_spin(9). (authored by kib). · Explain WhyJul 23 2016, 5:31 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

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head/
share/
man/
man9/
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46 lines
sys/
kern/
28 lines
sys/
44 lines

Diff 18697

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head/share/man/man9/Makefile

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head/share/man/man9/mutex.9

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head/sys/kern/kern_mutex.c

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head/sys/sys/mutex.h

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