11–13 Dec 2025
Asia/Tokyo timezone

CMA allocations fail due to pinned MOVABLE pages

Not scheduled
20m
Kernel Memory Management MC Kernel Memory Management MC

Speakers

Juan Yescas (Google) Kalesh Singh (Google)

Description

When device drivers reserve big blocks of MIGRATE_CMA pages, the underutilized MIGRATE_CMA can be used for MIGRATE_MOVABLE requests and these pages can be short-term pin for DMA, so if we require MIGRATE_CMA pages, the allocations might fail.

This topic has been discussed in:

https://lore.kernel.org/all/882b566c-34d6-4e68-9447-6c74a0693f18@redhat.com/T/#u

https://lore.kernel.org/all/CAJDx_rhu5jj6EEhnPQGa6qDDWTDm-6Ac0ucUA2HVT-9yRvCNhQ@mail.gmail.com/

The goal of the talk is to discuss the different solutions for the problem and pick the most adequate for this issue.

Primary authors

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