From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754109AbeDWCfb (ORCPT ); Sun, 22 Apr 2018 22:35:31 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44250 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753945AbeDWCbW (ORCPT ); Sun, 22 Apr 2018 22:31:22 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel.opensrc@gmail.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 14/22] rcu: Add leaf-node macros Date: Sun, 22 Apr 2018 19:32:19 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20180423023150.GA21533@linux.vnet.ibm.com> References: <20180423023150.GA21533@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18042302-0056-0000-0000-0000044375FA X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008903; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000257; SDB=6.01021888; UDB=6.00521536; IPR=6.00801123; MB=3.00020718; MTD=3.00000008; XFM=3.00000015; UTC=2018-04-23 02:31:19 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042302-0057-0000-0000-000008877F33 Message-Id: <1524450747-22778-14-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-23_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804230025 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This commit adds rcu_first_leaf_node() that returns a pointer to the first leaf rcu_node structure in the specified RCU flavor and an rcu_is_leaf_node() that returns true iff the specified rcu_node structure is a leaf. This commit also uses these macros where appropriate. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 11 ++++++++--- kernel/rcu/tree.c | 4 ++-- kernel/rcu/tree_plugin.h | 4 ++-- 3 files changed, 12 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 7a693e31184a..5b5bb9ee2e20 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -270,6 +270,12 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) } } +/* Returns first leaf rcu_node of the specified RCU flavor. */ +#define rcu_first_leaf_node(rsp) ((rsp)->level[rcu_num_lvls - 1]) + +/* Is this rcu_node a leaf? */ +#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1) + /* * Do a full breadth-first scan of the rcu_node structures for the * specified rcu_state structure. @@ -284,8 +290,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) * rcu_node tree with but one rcu_node structure, this loop is a no-op. */ #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ - for ((rnp) = &(rsp)->node[0]; \ - (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++) + for ((rnp) = &(rsp)->node[0]; !rcu_is_leaf_node(rsp, rnp); (rnp)++) /* * Scan the leaves of the rcu_node hierarchy for the specified rcu_state @@ -294,7 +299,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) * It is still a leaf node, even if it is also the root node. */ #define rcu_for_each_leaf_node(rsp, rnp) \ - for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \ + for ((rnp) = rcu_first_leaf_node(rsp); \ (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 19d9475d74f2..08b72dd02d88 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2405,7 +2405,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, return; } WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */ - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1 && + WARN_ON_ONCE(!rcu_is_leaf_node(rnp) && rcu_preempt_blocked_readers_cgp(rnp)); rnp->qsmask &= ~mask; trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, @@ -4063,7 +4063,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) init_swait_queue_head(&rsp->gp_wq); init_swait_queue_head(&rsp->expedited_wq); - rnp = rsp->level[rcu_num_lvls - 1]; + rnp = rcu_first_leaf_node(rsp); for_each_possible_cpu(i) { while (i > rnp->grphi) rnp++; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index d37b9bb3f481..b999032e9466 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -182,7 +182,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) raw_lockdep_assert_held_rcu_node(rnp); WARN_ON_ONCE(rdp->mynode != rnp); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); /* * Decide where to queue the newly blocked task. In theory, @@ -533,7 +533,7 @@ void rcu_read_unlock_special(struct task_struct *t) rnp = t->rcu_blocked_node; raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ WARN_ON_ONCE(rnp != t->rcu_blocked_node); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); empty_norm = !rcu_preempt_blocked_readers_cgp(rnp); empty_exp = sync_rcu_preempt_exp_done(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ -- 2.5.2