On Wed, 21 Feb 2018 09:18:35 -0800 Shakeel Butt <shake...@google.com> wrote:
> On Wed, Feb 21, 2018 at 8:09 AM, Christopher Lameter <c...@linux.com> wrote: > > Another way to solve this is to switch the user context right? > > > > Isnt it possible to avoid these patches if do the allocation in another > > task context instead? > > > > Sorry, can you please explain what you mean by 'switch the user > context'. Is there any example in kernel which does something similar? > > Another way is by adding a field 'remote_memcg_to_charge' in > task_struct and set it before the allocation and in memcontrol.c, > first check if current->remote_memcg_to_charge is set otherwise use > the memcg of current. Also if we provide a wrapper to do that for the > user, there will be a lot less plumbing. > > Please let me know if you prefer this approach. That would be a lot simpler. Passing function arguments via task_struct is a bit dirty but is sometimes sooo effective. You should've seen how much mess task_struct.journal_info avoided! And reclaim_state. And one always wonders whether we should do a local save/restore before modifying the task_struct field, so it nests. What do others think? Maybe we can rename task_struct.reclaim_state to `struct task_mm_state *task_mm_state", add remote_memcg_to_charge to struct task_mm_state and avoid bloating the task_struct?
