On Thu, Mar 05, 2026 at 10:22:35AM -0800, Boqun Feng wrote:
> Hi Paul,
>
> On Wed, Mar 04, 2026 at 04:01:19PM -0800, Paul E. McKenney wrote:
> > As of v7.0-rc1, architectures that support preemption, including x86 and
> > arm64, no longer support CONFIG_PREEMPT_NONE or CONFIG_PREEMPT_VOLUNTARY.
> > Attempting to build kernels with these two Kconfig options results in
> > .config errors. This commit therefore switches such rcutorture scenarios
> > to CONFIG_PREEMPT_LAZY.
> >
> > Signed-off-by: Paul E. McKenney <[email protected]>
> >
> > ---
> >
> > Changes since v2:
> >
> > o Fold in c69ac5693540 ("rcutorture: Adjust scenarios for default
> > lazy preemption")
> >
>
> I'm not sure I got what the "Fold" here means? I think you didn't do the
> fold? Because..
>
> > Changes since v1:
> >
> > o Add CONFIG_PREEMPT_DYNAMIC=n in order to test non-preemptible RCU.
> >
> > o Remove CONFIG_PREEMPT_COUNT=n because it conflicts with
> > CONFIG_PREEMPT_LAZY=y.
> >
> > o Remove some stray conflicting CONFIG_PREEMPT_LAZY=n instances.
> >
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N
> > b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N
> > index 07f5e0a70ae70..f943cdfb0a741 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-N
> > @@ -2,7 +2,9 @@ CONFIG_RCU_TRACE=n
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=4
> > CONFIG_HOTPLUG_CPU=y
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_DYNAMIC=n
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > #CHECK#CONFIG_RCU_EXPERT=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-T
> > b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-T
> > index c70cf0405f248..06e4d1030279c 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-T
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-T
> > @@ -1,5 +1,6 @@
> > CONFIG_SMP=n
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-U
> > b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-U
> > index bc9eeabaa1b18..71da6e3e94886 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/SRCU-U
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/SRCU-U
> > @@ -1,5 +1,6 @@
> > CONFIG_SMP=n
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > @@ -7,4 +8,3 @@ CONFIG_PREEMPT_DYNAMIC=n
> > CONFIG_RCU_TRACE=n
> > CONFIG_DEBUG_LOCK_ALLOC=n
> > CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
> > -CONFIG_PREEMPT_COUNT=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TASKS02
> > b/tools/testing/selftests/rcutorture/configs/rcu/TASKS02
> > index 2f9fcffff5ae3..dd2bd4e08da4e 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TASKS02
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TASKS02
> > @@ -1,5 +1,6 @@
> > CONFIG_SMP=n
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TINY01
> > b/tools/testing/selftests/rcutorture/configs/rcu/TINY01
> > index bd5ed7b0da5f0..2be53bf60d65b 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TINY01
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TINY01
> > @@ -1,9 +1,9 @@
> > CONFIG_SMP=n
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > -CONFIG_PREEMPT_LAZY=n
>
> This is the line that was introduced by the said commit, hence this
> patch is still separate from that commit I think?
I *think* I have them folded/squashed correctly.
I pushed this out to my -rcu "dev" branch. The relevant commits are,
in order of increasing time of commit:
c69ac5693540 ("rcutorture: Adjust scenarios for default lazy preemption")
86126bc6d7ad ("rcutorture: Update due to x86 not supporting none/voluntary
preemption")
5631c1565493 ("Revert "rcutorture: Adjust scenarios for default lazy
preemption"")
6fd95cee7427 ("Revert "rcutorture: Update due to x86 not supporting
none/voluntary preemption"")
17c52d7b31a1 ("rcutorture: Update due to x86 not supporting none/voluntary
preemption")
The first was applied by Joel to the shared RCU tree, the second is in my
-rcu tree, and the last three are consecutive commits in my -rcu tree.
The following command gives no output, which I was interpreting as my
having done it correctly. But please double-check.
git diff 5631c1565493^..17c52d7b31a1
Thanx, Paul
> Regards,
> Boqun
>
> > #CHECK#CONFIG_TINY_RCU=y
> > CONFIG_HZ_PERIODIC=n
> > CONFIG_NO_HZ_IDLE=y
> > @@ -12,4 +12,3 @@ CONFIG_RCU_TRACE=n
> > #CHECK#CONFIG_RCU_STALL_COMMON=n
> > CONFIG_DEBUG_LOCK_ALLOC=n
> > CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
> > -CONFIG_PREEMPT_COUNT=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TINY02
> > b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
> > index 30439f6fc20e6..be8860342ef71 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TINY02
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TINY02
> > @@ -1,5 +1,6 @@
> > CONFIG_SMP=n
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
> > b/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
> > index 18efab346381a..8fb124c28f283 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TRACE01
> > @@ -1,7 +1,8 @@
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=5
> > CONFIG_HOTPLUG_CPU=y
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE04
> > b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
> > index 34aee1acb8662..ac857d5bcb222 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE04
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
> > @@ -1,11 +1,12 @@
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=8
> > +CONFIG_PREEMPT_LAZY=y
> > CONFIG_PREEMPT_NONE=n
> > -CONFIG_PREEMPT_VOLUNTARY=y
> > +CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > -CONFIG_PREEMPT_LAZY=n
> > #CHECK#CONFIG_TREE_RCU=y
> > +#CHECK#CONFIG_PREEMPT_RCU=n
> > CONFIG_HZ_PERIODIC=n
> > CONFIG_NO_HZ_IDLE=n
> > CONFIG_NO_HZ_FULL=y
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE05
> > b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
> > index 0513aa33c32c4..61d15b1b54d16 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE05
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
> > @@ -1,9 +1,10 @@
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=8
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_DYNAMIC=n
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > -CONFIG_PREEMPT_LAZY=n
> > #CHECK#CONFIG_TREE_RCU=y
> > CONFIG_HZ_PERIODIC=n
> > CONFIG_NO_HZ_IDLE=y
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE06
> > b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
> > index cc3ea23c76557..0e090bb68a0f6 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE06
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
> > @@ -1,10 +1,12 @@
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=8
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_DYNAMIC=n
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > -CONFIG_PREEMPT_LAZY=n
> > #CHECK#CONFIG_TREE_RCU=y
> > +#CHECK#CONFIG_PREEMPT_RCU=n
> > CONFIG_HZ_PERIODIC=n
> > CONFIG_NO_HZ_IDLE=y
> > CONFIG_NO_HZ_FULL=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE10
> > b/tools/testing/selftests/rcutorture/configs/rcu/TREE10
> > index 420632b030dc4..b2ce37861e71a 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE10
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE10
> > @@ -6,6 +6,7 @@ CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_PREEMPT_DYNAMIC=n
> > #CHECK#CONFIG_TREE_RCU=y
> > +CONFIG_PREEMPT_RCU=n
> > CONFIG_HZ_PERIODIC=n
> > CONFIG_NO_HZ_IDLE=y
> > CONFIG_NO_HZ_FULL=n
> > diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL
> > b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL
> > index 5d546efa68e83..696fba9968c60 100644
> > --- a/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL
> > +++ b/tools/testing/selftests/rcutorture/configs/rcu/TRIVIAL
> > @@ -1,6 +1,8 @@
> > CONFIG_SMP=y
> > CONFIG_NR_CPUS=8
> > -CONFIG_PREEMPT_NONE=y
> > +CONFIG_PREEMPT_DYNAMIC=n
> > +CONFIG_PREEMPT_LAZY=y
> > +CONFIG_PREEMPT_NONE=n
> > CONFIG_PREEMPT_VOLUNTARY=n
> > CONFIG_PREEMPT=n
> > CONFIG_HZ_PERIODIC=n
> >
