drm/pagemap: Add a drm_pagemap cache and shrinker

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Pagemaps are costly to set up and tear down, and they consume a lot
of system memory for the struct pages. Ideally they should be
created only when needed.

Add a caching mechanism to allow doing just that: Create the drm_pagemaps
when needed for migration. Keep them around to avoid destruction and
re-creation latencies and destroy inactive/unused drm_pagemaps on memory
pressure using a shrinker.

Only add the helper functions. They will be hooked up to the xe driver
in the upcoming patch.

v2:
- Add lockdep checking for drm_pagemap_put(). (Matt Brost)
- Add a copyright notice. (Matt Brost)

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> # For merging through drm-xe.
Link: https://patch.msgid.link/20251219113320.183860-8-thomas.hellstrom@linux.intel.com

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This commit is contained in:

Thomas Hellström 2025-12-19 12:33:03 +01:00

parent a26084328a

commit 77f14f2f2d

5 changed files with 613 additions and 18 deletions

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3

drivers/gpu/drm/Makefile

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83

drivers/gpu/drm/drm_pagemap.c

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450

drivers/gpu/drm/drm_pagemap_util.c

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53

include/drm/drm_pagemap.h

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42

include/drm/drm_pagemap_util.h

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