On Tue, Sep 22, 2020 at 11:43:26PM +0200, Frederic Weisbecker wrote: > On Mon, Sep 21, 2020 at 05:27:32PM -0700, Paul E. McKenney wrote: > > On Mon, Sep 21, 2020 at 02:43:40PM +0200, Frederic Weisbecker wrote: > > > This simplify the usage of this API and avoid checking the kernel > > > config from the callers. > > > > > > Suggested-by: Paul E. McKenney <paul...@kernel.org> > > > Signed-off-by: Frederic Weisbecker <frede...@kernel.org> > > > Cc: Paul E. McKenney <paul...@kernel.org> > > > Cc: Josh Triplett <j...@joshtriplett.org> > > > Cc: Steven Rostedt <rost...@goodmis.org> > > > Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> > > > Cc: Lai Jiangshan <jiangshan...@gmail.com> > > > Cc: Joel Fernandes <j...@joelfernandes.org> > > > > Nice cleanup! I clearly should have done it this way to start with. > > > > Any reason I shouldn't pull this into -rcu right now? > > I think that very one can be applied indeed.
Very well! I had to hand-apply it due to recent -rcu thrash, and as usual I could not resist wordsmithing the commit log. Please let me know if I messed anything up. Thanx, Paul ------------------------------------------------------------------------ commit 99a2a9b00b1f44019e5667cdbd44b8eb82e9f0a9 Author: Frederic Weisbecker <frede...@kernel.org> Date: Mon Sep 21 14:43:40 2020 +0200 rcu: Implement rcu_segcblist_is_offloaded() config dependent This commit simplifies the use of the rcu_segcblist_is_offloaded() API so that its callers no longer need to check the RCU_NOCB_CPU Kconfig option. Note that rcu_segcblist_is_offloaded() is defined in the header file, which means that the generated code should be just as efficient as before. Suggested-by: Paul E. McKenney <paul...@kernel.org> Signed-off-by: Frederic Weisbecker <frede...@kernel.org> Cc: Paul E. McKenney <paul...@kernel.org> Cc: Josh Triplett <j...@joshtriplett.org> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Cc: Lai Jiangshan <jiangshan...@gmail.com> Cc: Joel Fernandes <j...@joelfernandes.org> Signed-off-by: Paul E. McKenney <paul...@kernel.org> diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 5c293af..492262b 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -62,7 +62,7 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) /* Is the specified rcu_segcblist offloaded? */ static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp) { - return rsclp->offloaded; + return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded; } /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2424e2a..6d9ec8e 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1609,8 +1609,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp) { bool ret = false; bool need_qs; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); raw_lockdep_assert_held_rcu_node(rnp); @@ -2054,8 +2053,7 @@ static void rcu_gp_cleanup(void) needgp = true; } /* Advance CBs to reduce false positives below. */ - offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) { WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT); WRITE_ONCE(rcu_state.gp_req_activity, jiffies); @@ -2254,8 +2252,7 @@ rcu_report_qs_rdp(struct rcu_data *rdp) unsigned long flags; unsigned long mask; bool needwake = false; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); struct rcu_node *rnp; WARN_ON_ONCE(rdp->cpu != smp_processor_id()); @@ -2423,8 +2420,7 @@ static void rcu_do_batch(struct rcu_data *rdp) { int div; unsigned long flags; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); struct rcu_head *rhp; struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl); long bl, count; @@ -2681,8 +2677,7 @@ static __latent_entropy void rcu_core(void) unsigned long flags; struct rcu_data *rdp = raw_cpu_ptr(&rcu_data); struct rcu_node *rnp = rdp->mynode; - const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - rcu_segcblist_is_offloaded(&rdp->cblist); + const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist); if (cpu_is_offline(smp_processor_id())) return; @@ -2984,8 +2979,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func) rcu_segcblist_n_cbs(&rdp->cblist)); /* Go handle any RCU core processing required. */ - if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) && - unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) { + if (unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) { __call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */ } else { __call_rcu_core(rdp, head, flags); @@ -3739,8 +3733,7 @@ static int rcu_pending(int user) /* Has RCU gone idle with this CPU needing another grace period? */ if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) && - (!IS_ENABLED(CONFIG_RCU_NOCB_CPU) || - !rcu_segcblist_is_offloaded(&rdp->cblist)) && + !rcu_segcblist_is_offloaded(&rdp->cblist) && !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL)) return 1;