Re: [PATCH v2 00/12] mm: make userland page table freeing RCU-safe

On Tue, 08 Sep 2026 13:32:09 +0100 "Lorenzo Stoakes (ARM)" [off-list ref] wrote:

The majority of architectures in the kernel defer page table freeing until
an RCU grace period has elapsed, this series converts all remaining
architectures to do so too and eliminates CONFIG_MMU_GATHER_RCU_TABLE_FREE
altogether.

This is important because it enables safe lockless page table walking under
RCU alone.

Doing so allows for reduced lock contention, avoids lock ordering concerns
and enables fast, efficient and correct page table walking as a result.

Additionally it removes a bunch of code and architecture-specific behaviour
which is always a beneficial thing to do.

Thanks.  It's early and unreviewed, but this is mainly an
if-it-compiles-its-good thing, so I'll add it for exposure to the
build/checker universe.

However some arches required extra attention - sh-X2, m68k-motorola and
sparc32.

OK.  Please lmk later if you think additional reviewer/tester attention
is desirable in these areas.