linuxkpi: Add `split_page()`
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Authored by dumbbell on Mon, Aug 10, 5:31 PM.

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linuxkpi

Summary

This function is supposed to split large pages into an array of PAGE_SIZE-sized pages, with correct refcounting. This is apparently used to allow some drivers to free a part of a large page only.

I don't think we use large pages in linuxkpi. Therefore, this new function is curently a no-op.

The DRM drivers TTM memory manager started to use it in Linux 6.15.

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dumbbell created this revision.Mon, Aug 10, 5:31 PM

Herald added subscribers: emaste, imp. · View Herald TranscriptMon, Aug 10, 5:31 PM

dumbbell requested review of this revision.Mon, Aug 10, 5:31 PM

I don't think we use large pages in linuxkpi. Therefore, this new function is curently a no-op.

Is there a way we can add either a compile-time error or KASSERT to ensure this remains the case?

dumbbell added a parent revision: D58761: linuxkpi: Include <linux/page-flags.h> from <linux/mm.h>.Mon, Aug 10, 5:34 PM

dumbbell added a child revision: D58763: linuxkpi: Add several folio-related functions.

In D58762#1348310, @emaste wrote:

I don't think we use large pages in linuxkpi. Therefore, this new function is curently a no-op.

Is there a way we can add either a compile-time error or KASSERT to ensure this remains the case?

Or at least at the pr_debug("%s:TODO\n", func). I really should make that a macro and replace all occurrences.

emaste added a project: linuxkpi.Mon, Aug 17, 4:58 PM

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sys/

compat/

linuxkpi/

common/

include/

linux/

mm.h

5 lines

Diff 183797

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sys/compat/linuxkpi/common/include/linux/mm.h

linuxkpi: Add `split_page()`Needs ReviewPublicActions