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radix_tree: for lookup_le find low bits better
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Authored by dougm on Jul 30 2023, 8:36 PM.
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Details

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alc
Summary

At one point, lookup_le needs to know if any of the first 'slot' bits in popmap are nonzero. Since we know that popmap is nonzero, this change reforms that test in a way that saves one byte on amd64.

As it happens, saving one byte in vm_radix_lookup_le means saving 15 nop bytes as well, so that the function shrinks by 16 bytes.

Test Plan

Tested by building a kernel.

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Event Timeline

dougm requested review of this revision.Jul 30 2023, 8:36 PM
dougm created this revision.

Shrink code size by 2 more bytes.

Update to leave out vm_radix.c.