Re: [PATCH 0/4 v2] rcu/nocb: Shrinker related boring fixes

From: Paul E. McKenney
Date: Mon Apr 24 2023 - 13:35:33 EST


On Wed, Mar 29, 2023 at 06:01:59PM +0200, Frederic Weisbecker wrote:
> Changes since v1 (https://lore.kernel.org/lkml/20230322194456.2331527-1-frederic@xxxxxxxxxx/):
>
> * Use mutex_trylock() to avoid inverted dependency chain against
> allocations.
>
> * WARN if an rdp is part of nocb mask but is not offloaded
>
> Tested through shrinker debugfs interface.

I pulled this one in, thank you!

As discussed, we do need some way to test lazy callbacks, but that should
not block this series. And it might well be a separate test.

Thanx, Paul

> Frederic Weisbecker (4):
> rcu/nocb: Protect lazy shrinker against concurrent (de-)offloading
> rcu/nocb: Fix shrinker race against callback enqueuer
> rcu/nocb: Recheck lazy callbacks under the ->nocb_lock from shrinker
> rcu/nocb: Make shrinker to iterate only NOCB CPUs
>
> kernel/rcu/tree_nocb.h | 52 ++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 47 insertions(+), 5 deletions(-)
>
> --
> 2.34.1
>