Re: [PATCH v5 1/8] alpha: load the MMU context when switch_mm() switches the current task

[Magnus Lindholm]

Hi Matt,

On Sun, Oct 11, 2026 at 1:32 AM Matt Turner <mattst88@xxxxxxxxx> wrote:
>
> On Sat, Oct 10, 2026 at 04:24:27PM +0200, Magnus Lindholm wrote:
> > do_shoot_lazy_tlb(), which switches to init_mm from an IPI. None explicitly
> > loads the context, so the task can carry on running
> > under whatever was loaded before while current->mm says otherwise.
>
> Two small things if you touch this changelog again when applying,
> neither worth a v6.
>
> The second line above is short.
>
> "while current->mm says otherwise" only describes kthread_use_mm(). The
> other two callers change active_mm and leave current->mm NULL.
>
> > Signed-off-by: Magnus Lindholm <linmag7@xxxxxxxxx>
> > Tested-by: Matt Turner <mattst88@xxxxxxxxx>
> > Reviewed-by: Matt Turner <mattst88@xxxxxxxxx>
>
> Your Signed-off-by is last on patches 2-8 and first here.

Thanks, I've reworded the changelog in for-next to distinguish
kthread_use_mm(), which changes current->mm, from the other two callers,
which change active_mm while leaving current->mm NULL. I've also fixed
the line wrapping. There are no code changes for this patch.

The combined TLB v5 and MMU v4 stack has now also completed an extended
SMP compaction soak on the ES40, with three CPUs online and
CONFIG_COMPACTION=y.

Over an hour, all 23 cycles passed:
  - 207 lost-store rounds
  - 207 stale-read rounds
  - 230 shared-mapping writeback rounds on ext4

Compaction was triggered repeatedly during each cycle, and
pgmigrate_success increased by 193374. Continuous kernel logging showed
no new warnings or errors, only the expected drop_caches notices from
the writeback test. The writeback settings were restored and checked
after every cycle.

Thanks,
Magnus