Re: [PATCH 1/7] mm: allocate mm_cpumask dynamically based on nr_cpu_ids

From: Ingo Molnar
Date: Sun Jul 15 2018 - 18:59:58 EST



* Rik van Riel <riel@xxxxxxxxxxx> wrote:

> The mm_struct always contains a cpumask bitmap, regardless of
> CONFIG_CPUMASK_OFFSTACK. That means the first step can be to
> simplify things, and simply have one bitmask at the end of the
> mm_struct for the mm_cpumask.
>
> This does necessitate moving everything else in mm_struct into
> an anonymous sub-structure, which can be randomized when struct
> randomization is enabled.
>
> The second step is to determine the correct size for the
> mm_struct slab object from the size of the mm_struct
> (excluding the cpu bitmap) and the size the cpumask.
>
> For init_mm we can simply allocate the maximum size this
> kernel is compiled for, since we only have one init_mm
> in the system, anyway.
>
> Pointer magic by Mike Galbraith, to evade -Wstringop-overflow
> getting confused by the dynamically sized array.
>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
> Signed-off-by: Mike Galbraith <efault@xxxxxx>

Is this an Acked-by in disguise, or did this patch route via Mike?

Thanks,

Ingo