Re: linux-next: manual merge of the rcu tree with the block tree

From: Jens Axboe
Date: Fri Feb 12 2021 - 10:28:12 EST


On 2/11/21 10:38 AM, Paul E. McKenney wrote:
> On Thu, Feb 11, 2021 at 04:48:52PM +1100, Stephen Rothwell wrote:
>> Hi all,
>>
>> Today's linux-next merge of the rcu tree got conflicts in:
>>
>> include/linux/rcupdate.h
>> kernel/rcu/tree.c
>> kernel/rcu/tree_plugin.h
>>
>> between commits:
>>
>> 3a7b5c87a0b2 ("rcu/nocb: Perform deferred wake up before last idle's need_resched() check")
>> e4234f21d2ea ("rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callers")
>> 14bbd41d5109 ("entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point")
>
> Frederic had me move these out of the section of the -rcu commits for
> the v5.12 merge window, saying that they were not yet ready.
>
> Jens, are these needed to prevent failures in the block tree? If so,
> there were some commits added late in v5.11 that might also get rid
> of your failures. If those v5.11 commits don't help the block tree,
> let's figure out what we need to do here... ;-)

I pulled these in from sched/core looks like, because there was a dependency
for 2 block fixes from Sebastian:

https://git.kernel.dk/cgit/linux-block/log/?h=for-5.12/block-ipi

But I think I made a mistake in that it should've been sched/smp instead,
which would likely get rid of this issue too? I'll rebase it, it's just
a single topic branch with just those two patches on top.

--
Jens Axboe