Re: [RFC GIT PULL rcu/next] RCU/hotplug fix

From: Jeffrey Hugo
Date: Thu Aug 24 2017 - 10:49:57 EST


On 8/24/2017 8:35 AM, Paul E. McKenney wrote:
On Thu, Aug 24, 2017 at 09:53:20AM +0200, Ingo Molnar wrote:

* Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx> wrote:

This commit has been exposed to 0day test robot and -next testing
and is available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git for-mingo

for you to fetch changes up to a58163d8ca2c8d288ee9f95989712f98473a5ac2:

rcu: Migrate callbacks earlier in the CPU-offline timeline (2017-07-25 13:03:43 -0700)

----------------------------------------------------------------
Paul E. McKenney (1):
rcu: Migrate callbacks earlier in the CPU-offline timeline

include/linux/rcupdate.h | 1 +
kernel/cpu.c | 1 +
kernel/rcu/tree.c | 209 +++++++++++++++++++++++++----------------------
3 files changed, 115 insertions(+), 96 deletions(-)

Pulled, thanks Paul!

Ingo


Ingo,

We've been keeping an eye on this fix, so I'm trying to ascertain it's status.
For my information, is this expected to hit Linus' tree in 4.13, or wait until
the 4.14 merge window?

It's for v4.14, it's a pretty large (and thus risky) commit that came in
relatively late. If it's problem-free it can be sent to -stable.

If Paul insists I can try and send it to Linus, but it's getting fairly late
in the cycle.

Hugo, I was interpreting your email of August 22nd as meaning that
the problem no longer existed in mainline:

https://marc.info/?l=linux-kernel&m=150343524911301&w=2

If my interpretation is correct, then this commit can wait until the
upcoming merge window. As Ingo says, I can send patches to -stable
(and backporting is required, BTW).

If my interpretation is incorrect, please let me know what the situation
really is.

Thanx, Paul


Sorry for any confusion. Yes, that interpretation is correct. I agree, it is late in the cycle, and I am not advocating for inclusion into 4.13. We have internal processes concerning upstream fixes, and it is helpful to identify exactly when a fix is expected to hit Linus' tree - none of which is particularly important or relevant to the community, I'm just trying to bridge a few gaps.

4.14 merge window is perfectly fine. I will plan on that. Thanks for the clarification, and a huge thanks for looking at the issue and solving it.

--
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.