From: "Paul E. McKenney" paulmck@kernel.org
This commit creates a new srcu-fast option for the refscale.scale_type module parameter that selects srcu_read_lock_fast() and srcu_read_unlock_fast().
Signed-off-by: Paul E. McKenney paulmck@kernel.org Cc: Alexei Starovoitov ast@kernel.org Cc: Andrii Nakryiko andrii@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Kent Overstreet kent.overstreet@linux.dev Cc: bpf@vger.kernel.org Signed-off-by: Boqun Feng boqun.feng@gmail.com --- kernel/rcu/refscale.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 1b47376acdc4..f11a7c2af778 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -216,6 +216,36 @@ static const struct ref_scale_ops srcu_ops = { .name = "srcu" };
+static void srcu_fast_ref_scale_read_section(const int nloops) +{ + int i; + struct srcu_ctr __percpu *scp; + + for (i = nloops; i >= 0; i--) { + scp = srcu_read_lock_fast(srcu_ctlp); + srcu_read_unlock_fast(srcu_ctlp, scp); + } +} + +static void srcu_fast_ref_scale_delay_section(const int nloops, const int udl, const int ndl) +{ + int i; + struct srcu_ctr __percpu *scp; + + for (i = nloops; i >= 0; i--) { + scp = srcu_read_lock_fast(srcu_ctlp); + un_delay(udl, ndl); + srcu_read_unlock_fast(srcu_ctlp, scp); + } +} + +static const struct ref_scale_ops srcu_fast_ops = { + .init = rcu_sync_scale_init, + .readsection = srcu_fast_ref_scale_read_section, + .delaysection = srcu_fast_ref_scale_delay_section, + .name = "srcu-fast" +}; + static void srcu_lite_ref_scale_read_section(const int nloops) { int i; @@ -1163,7 +1193,7 @@ ref_scale_init(void) long i; int firsterr = 0; static const struct ref_scale_ops *scale_ops[] = { - &rcu_ops, &srcu_ops, &srcu_lite_ops, RCU_TRACE_OPS RCU_TASKS_OPS + &rcu_ops, &srcu_ops, &srcu_fast_ops, &srcu_lite_ops, RCU_TRACE_OPS RCU_TASKS_OPS &refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops, &sched_clock_ops, &clock_ops, &jiffies_ops, &typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops,