RCU branching for the v4.19 merge window

[Paul E. McKenney]

Hello, Steve!

Another year, another difficult-to-branch set of RCU commits.

In happy contrast to last year, I can make some branches (SRCU, some
of the torture commits, and a few miscellaneous commits), but I will
likely end up with several short branches and one huge one.  My thought
is to keep the long branch, but email the patches out in a few separate
serieses, with each depending on its predecessor.  For example, one series
from the big branch would be folding the ->gpnum and ->completed fields
into a single ->gp_seq, which helps the RCU-flavor consolidation task.
Another series suppresses some rare false-positive splats that have been
plaguing me for more than a year.  Yet another series within this huge
branch applies and optimizes funnel locking for grace-period startup.

The problem is that the conversion to ->gp_seq has a very large footprint,
which of course generates lots of conflicts.  I could of course collapse
these commits into a single commit, but if I did that I would also defer
to the merge window following v4.19 due to the resulting loss of bisection
within that change.

Any advice?

The commits are for-mingo..rcu/dev in my -rcu tree.

							Thanx, Paul