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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 26 Mar 2019 23:22:27 -0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x2QNMQOU8913014 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 26 Mar 2019 23:22:26 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 48856B206C; Tue, 26 Mar 2019 23:22:26 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 16DE1B2067; Tue, 26 Mar 2019 23:22:26 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.188]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 26 Mar 2019 23:22:26 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id D3EE516C610F; Tue, 26 Mar 2019 16:22:26 -0700 (PDT) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, 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@joelfernandes.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 07/11] rcu: Move FAST_NO_HZ stall-warning code to tree_stall.h Date: Tue, 26 Mar 2019 16:22:21 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190326232208.GA20384@linux.ibm.com> References: <20190326232208.GA20384@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19032623-0064-0000-0000-000003C06EC8 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010820; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000282; SDB=6.01180136; UDB=6.00617574; IPR=6.00960851; MB=3.00026169; MTD=3.00000008; XFM=3.00000015; UTC=2019-03-26 23:22:31 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19032623-0065-0000-0000-00003CD8B779 Message-Id: <20190326232225.21332-7-paulmck@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-26_15:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=13 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903260157 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This commit further consolidates the stall-warning code by moving print_cpu_stall_info() and its helper functions along with zero_cpu_stall_ticks() to kernel/rcu/tree_stall.h. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.h | 1 - kernel/rcu/tree_plugin.h | 80 ---------------------------------------- kernel/rcu/tree_stall.h | 80 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+), 81 deletions(-) diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index d73472af49e7..49bf3b00bb50 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -416,7 +416,6 @@ static void rcu_prepare_for_idle(void); static bool rcu_preempt_has_tasks(struct rcu_node *rnp); static bool rcu_preempt_need_deferred_qs(struct task_struct *t); static void rcu_preempt_deferred_qs(struct task_struct *t); -static void print_cpu_stall_info(int cpu); static void zero_cpu_stall_ticks(struct rcu_data *rdp); static bool rcu_nocb_cpu_needs_barrier(int cpu); static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 2df5bb04fd7a..a1f9d7c15bd8 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1528,86 +1528,6 @@ static void rcu_cleanup_after_idle(void) #endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */ -#ifdef CONFIG_RCU_FAST_NO_HZ - -static void print_cpu_stall_fast_no_hz(char *cp, int cpu) -{ - struct rcu_data *rdp = &per_cpu(rcu_data, cpu); - - sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c", - rdp->last_accelerate & 0xffff, jiffies & 0xffff, - ".l"[rdp->all_lazy], - ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)], - ".D"[!rdp->tick_nohz_enabled_snap]); -} - -#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */ - -static void print_cpu_stall_fast_no_hz(char *cp, int cpu) -{ - *cp = '\0'; -} - -#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */ - -/* - * Print out diagnostic information for the specified stalled CPU. - * - * If the specified CPU is aware of the current RCU grace period, then - * print the number of scheduling clock interrupts the CPU has taken - * during the time that it has been aware. Otherwise, print the number - * of RCU grace periods that this CPU is ignorant of, for example, "1" - * if the CPU was aware of the previous grace period. - * - * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info. - */ -static void print_cpu_stall_info(int cpu) -{ - unsigned long delta; - char fast_no_hz[72]; - struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); - char *ticks_title; - unsigned long ticks_value; - - /* - * We could be printing a lot while holding a spinlock. Avoid - * triggering hard lockup. - */ - touch_nmi_watchdog(); - - ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq); - if (ticks_value) { - ticks_title = "GPs behind"; - } else { - ticks_title = "ticks this GP"; - ticks_value = rdp->ticks_this_gp; - } - print_cpu_stall_fast_no_hz(fast_no_hz, cpu); - delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq); - pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n", - cpu, - "O."[!!cpu_online(cpu)], - "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)], - "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)], - !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' : - rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' : - "!."[!delta], - ticks_value, ticks_title, - rcu_dynticks_snap(rdp) & 0xfff, - rdp->dynticks_nesting, rdp->dynticks_nmi_nesting, - rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), - READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart, - fast_no_hz); -} - -/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */ -static void zero_cpu_stall_ticks(struct rcu_data *rdp) -{ - rdp->ticks_this_gp = 0; - rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id()); - WRITE_ONCE(rdp->last_fqs_resched, jiffies); -} - #ifdef CONFIG_RCU_NOCB_CPU /* diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 7ef3b596e45f..19b915380a6f 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -223,6 +223,86 @@ static void panic_on_rcu_stall(void) panic("RCU Stall\n"); } +#ifdef CONFIG_RCU_FAST_NO_HZ + +static void print_cpu_stall_fast_no_hz(char *cp, int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_data, cpu); + + sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c", + rdp->last_accelerate & 0xffff, jiffies & 0xffff, + ".l"[rdp->all_lazy], + ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)], + ".D"[!rdp->tick_nohz_enabled_snap]); +} + +#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */ + +static void print_cpu_stall_fast_no_hz(char *cp, int cpu) +{ + *cp = '\0'; +} + +#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */ + +/* + * Print out diagnostic information for the specified stalled CPU. + * + * If the specified CPU is aware of the current RCU grace period, then + * print the number of scheduling clock interrupts the CPU has taken + * during the time that it has been aware. Otherwise, print the number + * of RCU grace periods that this CPU is ignorant of, for example, "1" + * if the CPU was aware of the previous grace period. + * + * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info. + */ +static void print_cpu_stall_info(int cpu) +{ + unsigned long delta; + char fast_no_hz[72]; + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + char *ticks_title; + unsigned long ticks_value; + + /* + * We could be printing a lot while holding a spinlock. Avoid + * triggering hard lockup. + */ + touch_nmi_watchdog(); + + ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq); + if (ticks_value) { + ticks_title = "GPs behind"; + } else { + ticks_title = "ticks this GP"; + ticks_value = rdp->ticks_this_gp; + } + print_cpu_stall_fast_no_hz(fast_no_hz, cpu); + delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq); + pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n", + cpu, + "O."[!!cpu_online(cpu)], + "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)], + "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)], + !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' : + rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' : + "!."[!delta], + ticks_value, ticks_title, + rcu_dynticks_snap(rdp) & 0xfff, + rdp->dynticks_nesting, rdp->dynticks_nmi_nesting, + rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu), + READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart, + fast_no_hz); +} + +/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */ +static void zero_cpu_stall_ticks(struct rcu_data *rdp) +{ + rdp->ticks_this_gp = 0; + rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id()); + WRITE_ONCE(rdp->last_fqs_resched, jiffies); +} + static void print_other_cpu_stall(unsigned long gp_seq) { int cpu; -- 2.17.1