Hi Frederic,

Thanks a lot for the detailed feedback on all patches, I will send the
next version soon with requested changes.


On Thu, May 28, 2026 at 1:14 PM Frederic Weisbecker [off-list ref] wrote:

Hi,

Le Fri, Apr 17, 2026 at 04:11:48PM -0700, Puranjay Mohan a écrit :

quoted

RCU callbacks only track normal grace period sequence numbers. This
means callbacks must wait for normal GPs even when expedited GPs have
already elapsed.

This series tracks both normal and expedited GP sequences in the
callback infrastructure using struct rcu_gp_oldstate, so callbacks
advance when either GP type completes.

What is the motivation behind this? When most callbacks don't have much latency
requirements between queue and invocation?

Right now there's an asymmetry: synchronize_rcu_expedited() callers
get fast object freeing, but call_rcu() callers never benefit from
those same grace periods even though they prove the exact same thing.
This series closes that gap, the callback infrastructure treats a
grace period as a grace period regardless of how it was driven. The
practical effect is faster memory reclaim: objects that could already
be safely freed stop sitting around waiting for the next normal GP.
I'll make this motivation clearer in the next version.

Thanks,
Puranjay