On 3 October 2026 17:17:19 BST, Kunwu Chan <[email protected]> wrote: >Add support for scaling atomic SRCU grace periods using >srcu_read_lock_atomic()/srcu_read_unlock_atomic() and >synchronize_srcu_atomic(). > >Suggested-by: Paul E. McKenney <[email protected]> >Signed-off-by: Kunwu Chan <[email protected]>
1: why didn't u cc me 2: why did you ommit my tag? I tend to review based on correctness, cuz idk pauls preferences, once I do I'll be a better rcu reviewer. >--- >Changes since v1: >- Rename srcu_atomic_ctlp to srcua and reuse srcu_ctlp for > SRCU operations, as suggested by Paul. >- Reuse the existing SRCU cleanup and completed helpers by > initializing srcu_ctlp in srcu_atomic_scale_init(). >- Add .stats using srcu_scale_stats(). >- Use "srcua" to match the existing "srcu" and "srcud" scale > type names. >- Use synchronize_srcu_atomic() for both normal and expedited > scale tests. > >v1: https://lore.kernel.org/all/[email protected]/ >Tested with kvm.sh --torture rcuscale scale_type=srcua on x86_64 and >arm64, alongside gp_exp=1 and PROVE_LOCKING=y: no warnings or lockdep >splats. >--- > kernel/rcu/rcuscale.c | 41 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 40 insertions(+), 1 deletion(-) > >diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c >index 1097ec15879c..b172882824ac 100644 >--- a/kernel/rcu/rcuscale.c >+++ b/kernel/rcu/rcuscale.c >@@ -293,6 +293,44 @@ static struct rcu_scale_ops srcud_ops = { > .name = "srcud" > }; > >+static struct srcu_struct srcua; >+ >+static int srcu_scale_atomic_read_lock(void) >+{ >+ return srcu_read_lock_atomic(srcu_ctlp); >+} >+ >+static void srcu_scale_atomic_read_unlock(int idx) >+{ >+ srcu_read_unlock_atomic(srcu_ctlp, idx); >+} >+ >+static void srcu_scale_atomic_synchronize(void) >+{ >+ synchronize_srcu_atomic(srcu_ctlp); >+} >+ >+static void srcu_atomic_scale_init(void) >+{ >+ srcu_ctlp = &srcua; >+ init_srcu_struct_atomic(srcu_ctlp); >+} >+ >+static struct rcu_scale_ops srcua_ops = { >+ .ptype = SRCU_FLAVOR, >+ .init = srcu_atomic_scale_init, >+ .cleanup = srcu_sync_scale_cleanup, >+ .readlock = srcu_scale_atomic_read_lock, >+ .readunlock = srcu_scale_atomic_read_unlock, >+ .get_gp_seq = srcu_scale_completed, >+ .gp_diff = rcu_seq_diff, >+ .exp_completed = srcu_scale_completed, >+ .sync = srcu_scale_atomic_synchronize, >+ .exp_sync = srcu_scale_atomic_synchronize, >+ .stats = srcu_scale_stats, >+ .name = "srcua" >+}; >+ > #ifdef CONFIG_TASKS_RCU > > /* >@@ -1110,7 +1148,8 @@ rcu_scale_init(void) > long i; > long j; > static struct rcu_scale_ops *scale_ops[] = { >- &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS >TASKS_TRACING_OPS >+ &rcu_ops, &srcu_ops, &srcua_ops, &srcud_ops, >+ TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS > }; > > if (!torture_init_begin(scale_type, verbose)) > >base-commit: d21906b0aa1e9573cdb5e7acaca44966b9d1dcd2 > --- Thanks! "I'm not a very positive person" - Linus torvalds
