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Differential D51431

pmap_demote_{l2,pde}: never invalidate wired mappings
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Authored by alc on Jul 20 2025, 12:37 AM.
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markj
andrew
manu
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rG7502c1f27082: pmap_demote_{l2,pde}: never invalidate wired mappings
Summary

Rather than demoting a superpage mapping that hasn't been accessed, we ordinarily invalidate it. However, if the mapping is wired, invalidation is problematic because the page fault to reinstantiate the mapping could sleep.

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alc created this revision.Jul 20 2025, 12:37 AM
Herald added a reviewer: andrew. · View Herald TranscriptJul 20 2025, 12:37 AM
Herald added a reviewer: andrew. · View Herald Transcript
Herald added a reviewer: manu. · View Herald Transcript
Herald added a subscriber: emaste. · View Herald Transcript
alc requested review of this revision.Jul 20 2025, 12:37 AM
kib accepted this revision.Jul 20 2025, 1:02 AM
This revision is now accepted and ready to land.Jul 20 2025, 1:02 AM
markj accepted this revision.Jul 21 2025, 1:46 PM

I believe this makes D49442 unnecessary, at least as far as fixing the bug is concerned.

alc added a comment.Jul 23 2025, 5:58 PM
In D51431#1174792, @markj wrote:

I believe this makes D49442 unnecessary, at least as far as fixing the bug is concerned.

Yes.

Closed by commit rG7502c1f27082: pmap_demote_{l2,pde}: never invalidate wired mappings (authored by alc). · Explain WhyJul 23 2025, 6:03 PM
This revision was automatically updated to reflect the committed changes.
alc added a commit: rG7502c1f27082: pmap_demote_{l2,pde}: never invalidate wired mappings.
Herald added a subscriber: imp. · View Herald TranscriptJul 23 2025, 6:03 PM

Revision Contents
Changeset List

PathSize
sys/
amd64/
amd64/
21 lines
arm64/
arm64/
24 lines

Diff 158955

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sys/amd64/amd64/pmap.c

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sys/arm64/arm64/pmap.c

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