vm_object: iterate to add pages in reconstruction
Needs ReviewPublic
Actions

Authored by dougm on Nov 21 2024, 8:39 AM.

Tags

None

Referenced Files

	F109850950: D47695.diff
	Mon, Feb 10, 8:23 AM

	Unknown Object (File)
	Mon, Jan 27, 2:46 PM

	Unknown Object (File)
	Mon, Jan 27, 2:44 PM

	Unknown Object (File)
	Mon, Jan 27, 2:33 PM

	Unknown Object (File)
	Mon, Jan 27, 12:26 AM

	Unknown Object (File)
	Jan 10 2025, 2:41 PM

	Unknown Object (File)
	Jan 2 2025, 6:23 AM

	Unknown Object (File)
	Dec 27 2024, 9:56 AM

View All 15 Files

Subscribers

kib

Details

Reviewers

markj
alc

Summary

Where vm_page_rename(), vm_object_collapse_scan(), and
vm_object_split() move pages from a source object to a destination,
use an iterator to add to the destination, as we already use an
iterator to remove from the source.

Also, remove a leftover, purposeless assignment.

Diff Detail

Lint

Lint Skipped

Unit

Tests Skipped

Event Timeline

dougm requested review of this revision.Nov 21 2024, 8:39 AM

dougm created this revision.

Drop the fix that @kib has committed separately.

markj added inline comments.Nov 28 2024, 1:56 PM

sys/vm/vm_page.c
2105	Shouldn't this result in a panic? A caller renaming a page over an existing page in the new object would be a bug.
sys/vm/vm_page.h
687–688	The parameter names don't match those in the function definition.

Add a panic when a page duplication is found. Match param names between definition and declaration.

Rebase, assuming this will be applied after D47829.

This change increased the cycles spent in both vm_object_split() and vm_object_collapse_scan() during a buildworld. It appears that we're not moving enough pages to overcome the startup costs of the iterator.