Messages in this thread Patch in this message | | | Date | Wed, 23 May 2018 12:23:49 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 3/4] rcu: Use better variable names in funnel locking loop |
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On Wed, May 23, 2018 at 09:06:17AM -0700, Paul E. McKenney wrote: > On Tue, May 22, 2018 at 11:38:14PM -0700, Joel Fernandes wrote: > > From: "Joel Fernandes (Google)" <joel@joelfernandes.org> > > > > The funnel locking loop in rcu_start_this_gp uses rcu_root as a > > temporary variable while walking the combining tree. This causes a > > tiresome exercise of a code reader reminding themselves that rcu_root > > may not be root. Lets just call it rnp, and rename other variables as > > well to be more appropriate. > > > > Original patch: https://patchwork.kernel.org/patch/10396577/ > > > > Signed-off-by: Joel Fernandes <joel@joelfernandes.org> > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> > > I used to have double Signed-off-by back when I was seconded to Linaro. > But I am guessing that you want the second and don't need the first > one. Unless you tell me otherwise, I will remove the first one on > my next rebase. > > Anyway, the new variable names are much more clear, good stuff, > queued for further review and testing, thank you!
And it looks to me like I should fold in the patchlet below to change to rnp_start in a comment. Please let me know if this would mess things up.
Thanx, Paul
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commit 94ce05d9d110b8c34eca6641ca5221c1b150e99f Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Date: Wed May 23 12:22:01 2018 -0700
fixup! rcu: Use better variable names in funnel locking loop Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 65e49282429c..fdba8ab95e2c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1550,11 +1550,11 @@ static bool rcu_start_this_gp(struct rcu_node *rnp_start, struct rcu_data *rdp, /* * Use funnel locking to either acquire the root rcu_node * structure's lock or bail out if the need for this grace period - * has already been recorded -- or has already started. If there - * is already a grace period in progress in a non-leaf node, no - * recording is needed because the end of the grace period will - * scan the leaf rcu_node structures. Note that rnp->lock must - * not be released. + * has already been recorded -- or if that grace period has in + * fact already started. If there is already a grace period in + * progress in a non-leaf node, no recording is needed because the + * end of the grace period will scan the leaf rcu_node structures. + * Note that rnp_start->lock must not be released. */ raw_lockdep_assert_held_rcu_node(rnp_start); trace_rcu_this_gp(rnp_start, rdp, gp_seq_req, TPS("Startleaf"));
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