Re: [PATCH] sched/core: Don't use dying mm as active_mm for kernel threads

[Waiman Long <longman@redhat.com>]

On 7/26/19 7:45 PM, Waiman Long wrote:
> It was found that a dying mm_struct where the owning task has exited can
> stay on as active_mm of kernel threads as long as no other user tasks
> run on those CPUs that use it as active_mm. This prolongs the life time
> of dying mm holding up memory and other resources that cannot be freed.
>
> Fix that by forcing the kernel threads to use init_mm as the active_mm
> if the previous active_mm is dying.
>
> Signed-off-by: Waiman Long <longman@redhat.com>
> ---
>  kernel/sched/core.c | 13 +++++++++++--
>  mm/init-mm.c        |  2 ++
>  2 files changed, 13 insertions(+), 2 deletions(-)


Sorry, I didn't realize that mm->owner depends on CONFIG_MEMCG. I will
need to refresh the patch and send out v2 when I am done testing.

Cheers,
Longman