Differential D56185

pmap: Do not use PMAP_LOCK_INIT with kernel_pmap
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Authored by markj on Mar 31 2026, 3:16 PM.

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Details

Reviewers

alc
kib
andrew
manu

Commits

rG90fc3831af15: pmap: Do not use PMAP_LOCK_INIT with kernel_pmap
rGc6a1c1260f02: pmap: Do not use PMAP_LOCK_INIT with kernel_pmap

Summary

The kernel_pmap lock is a bit special: it does not need the DUPOK flag,
and it really belongs to a different lock class. If it belongs to the
same class as regular pmap locks, than witness may report warnings when
performing UMA allocations under a regular pmap lock, if the allocation
triggers a pmap_growkernel() call.

Replace instances of PMAP_LOCK_INIT(kernel_pmap) with inline mtx_init()
calls to silence some witness warnings I see with some uncommitted test
programs.

Diff Detail

Repository

rG FreeBSD src repository

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Build Status

Buildable 71862
Build 68745: arc lint + arc unit

Event Timeline

markj created this revision.Mar 31 2026, 3:16 PM

Herald added a reviewer: andrew. · View Herald TranscriptMar 31 2026, 3:16 PM

Herald added a reviewer: andrew. · View Herald Transcript

Herald added a reviewer: manu. · View Herald Transcript

Herald added subscribers: riscv, jhibbits, emaste, imp. · View Herald Transcript

markj requested review of this revision.Mar 31 2026, 3:16 PM

Harbormaster completed remote builds in B71862: Diff 174641.Mar 31 2026, 3:16 PM

"... pmap locks, than witness ..." -> "... pmap locks, then witness ..."

This revision is now accepted and ready to land.Mar 31 2026, 3:20 PM

kib accepted this revision.Apr 1 2026, 2:09 AM

Closed by commit rGc6a1c1260f02: pmap: Do not use PMAP_LOCK_INIT with kernel_pmap (authored by markj). · Explain WhyApr 9 2026, 1:45 AM

This revision was automatically updated to reflect the committed changes.

markj added a commit: rGc6a1c1260f02: pmap: Do not use PMAP_LOCK_INIT with kernel_pmap.

markj added a commit: rG90fc3831af15: pmap: Do not use PMAP_LOCK_INIT with kernel_pmap.Apr 18 2026, 10:35 AM

Revision Contents
Changeset List

Path

Size

sys/

amd64/

amd64/

2 lines

arm/

arm/

2 lines

arm64/

arm64/

2 lines

i386/

i386/

2 lines

powerpc/

aim/

2 lines

2 lines

2 lines

booke/

2 lines

riscv/

riscv/

2 lines

Diff 174641

sys/amd64/amd64/pmap.c

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sys/arm/arm/pmap-v6.c

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sys/arm64/arm64/pmap.c

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sys/i386/i386/pmap.c

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sys/powerpc/aim/mmu_oea.c

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sys/powerpc/aim/mmu_oea64.c

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sys/powerpc/aim/mmu_radix.c

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sys/powerpc/booke/pmap.c

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sys/riscv/riscv/pmap.c

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