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Differential D45331

vm_phys: use ilog2(x) instead of fls(x)-1
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Authored by dougm on May 24 2024, 7:33 AM.
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alc
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rG543d55d79109: vm_phys: use ilog2(x) instead of fls(x)-1
Summary

One of these changes saves two instructions on an amd64 GENERIC-NODEBUG build. The rest are entirely cosmetic, because the compiler can deduce that x is nonzero, and avoid the needless test.

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rG FreeBSD src repository
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dougm requested review of this revision.May 24 2024, 7:33 AM
dougm created this revision.
alc accepted this revision.Jun 4 2024, 5:01 PM
alc added a subscriber: markj.

Please coordinate this with @markj given his lazy init change.

This revision is now accepted and ready to land.Jun 4 2024, 5:01 PM
markj added a comment.Jun 4 2024, 5:51 PM
In D45331#1037497, @alc wrote:

Please coordinate this with @markj given his lazy init change.

Please go ahead. It'll be easy to rebase past this patch and I need to retest before pushing.

Closed by commit rG543d55d79109: vm_phys: use ilog2(x) instead of fls(x)-1 (authored by dougm). · Explain WhyJun 4 2024, 6:08 PM
This revision was automatically updated to reflect the committed changes.
dougm added a commit: rG543d55d79109: vm_phys: use ilog2(x) instead of fls(x)-1.
Herald added a subscriber: imp. · View Herald TranscriptJun 4 2024, 6:08 PM

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sys/
vm/
10 lines

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sys/vm/vm_phys.c

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