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arch.7: Add a section describing the user address space
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Authored by markj on Apr 20 2025, 5:23 PM.
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Details

Summary

Provide some details about the user address space on each platform.
Document platforms which support multiple address spaces. I didn't
include 32-bit ABIs here, but maybe I should.

Diff Detail

Repository
rG FreeBSD src repository
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Build Status
Buildable 63601
Build 60485: arc lint + arc unit

Event Timeline

markj requested review of this revision.Apr 20 2025, 5:23 PM

I love this!

share/man/man7/arch.7
231

The width fields should contain the first longest rendered item in the column.

Fix column widths.

Mention that the KERN_PROC_VM_LAYOUT sysctl can be used to get more info about
a particular process.

share/man/man7/arch.7
255

This text would need an editing after D49913

266

Why is this sentence put under riscv paragraph? It is a generic statement.

markj marked 2 inline comments as done.

Re-order paragraphs.

share/man/man7/arch.7
255

Yes, I will keep this diff open until that one lands.

share/man/man7/arch.7
246
markj marked an inline comment as done.

Document vm.pmap.prefer_uva_la48

share/man/man7/arch.7
248

I believe this should be

.Xr sysctl 3
252
258

tunable can be used to force system into the 4-level paging mode, even if hardware supports 5-level paging. In particular, all processes would get 48bit AS.

268

Also proccontrol -m la48/la57 should be mentioned and cross-linked.

share/man/man7/arch.7
233

Should we use e.g. 256 TiB?

share/man/man7/arch.7
233

+1 for precise, internationally standardized units.

markj marked 7 inline comments as done.

Apply reviewer feedback.

This revision is now accepted and ready to land.Apr 30 2025, 1:28 PM