Re: [PATCH 2/4] signal: Make flush_sigqueue() use free_q to release memory

From: Waiman Long
Date: Fri Mar 22 2019 - 14:12:09 EST

On 03/22/2019 01:50 PM, Christopher Lameter wrote:
> On Fri, 22 Mar 2019, Waiman Long wrote:
>> I am looking forward to it.
> There is also alrady rcu being used in these paths. kfree_rcu() would not
> be enough? It is an estalished mechanism that is mature and well
> understood.
In this case, the memory objects are from kmem caches, so they can't
freed using kfree_rcu().

There are certainly overhead using the kfree_rcu(), or a
kfree_rcu()-like mechanism. Also I think the actual freeing is done at
SoftIRQ context which can be a problem if there are too many memory
objects to free.

I think what Oleg is trying to do is probably the most efficient way.