Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 17/22] EXP: rcu: Abstract addition of debugging information to assertion | Date | Sun, 22 Apr 2018 19:32:22 -0700 |
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Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcu/tree.c | 18 ++---------------- kernel/rcu/tree.h | 1 + kernel/rcu/tree_plugin.h | 29 +++++++++++++++++++++++++++++ 3 files changed, 32 insertions(+), 16 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 6ad2ac34558f..3bfd1519d378 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2147,22 +2147,8 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) */ rcu_for_each_node_breadth_first(rsp, rnp) { raw_spin_lock_irq_rcu_node(rnp); -#ifdef CONFIG_PREEMPT_RCU - if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp))) { - int i; - struct task_struct *t; - - pr_info("%s: grp: %d-%d level: %d ->gp_tasks %p ->exp_tasks %p &->blkd_tasks: %p offset: %u\n", __func__, rnp->grplo, rnp->grphi, rnp->level, rnp->gp_tasks, rnp->exp_tasks, &rnp->blkd_tasks, (unsigned int)offsetof(typeof(*rnp), blkd_tasks)); - pr_cont("\t->blkd_tasks"); - i = 0; - list_for_each_entry(t, &rnp->blkd_tasks, rcu_node_entry) { - pr_cont(" %p", t); - if (++i >= 10) - break; - } - pr_cont("\n"); - } -#endif /* #ifdef CONFIG_PREEMPT_RCU */ + if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp))) + dump_blkd_tasks(rnp, 10); WARN_ON_ONCE(rnp->qsmask); WRITE_ONCE(rnp->completed, rsp->gpnum); rdp = this_cpu_ptr(rsp->rda); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 0b3a90ebe225..23ae7c00d3c5 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -428,6 +428,7 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); static void rcu_preempt_check_callbacks(void); void call_rcu(struct rcu_head *head, rcu_callback_t func); static void __init __rcu_init_preempt(void); +static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck); static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags); static void rcu_preempt_boost_start_gp(struct rcu_node *rnp); static void invoke_rcu_callbacks_kthread(void); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index b999032e9466..a2ae6b49f900 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -841,6 +841,27 @@ void exit_rcu(void) __rcu_read_unlock(); } +/* + * Dump the blocked-tasks state, but limit the list dump to the + * specified number of elements. + */ +static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck) +{ + int i; + struct list_head *lhp; + + lockdep_assert_held(&rnp->lock); + pr_info("%s: grp: %d-%d level: %d ->gp_tasks %p ->exp_tasks %p &->blkd_tasks: %p offset: %u\n", __func__, rnp->grplo, rnp->grphi, rnp->level, rnp->gp_tasks, rnp->exp_tasks, &rnp->blkd_tasks, (unsigned int)offsetof(typeof(*rnp), blkd_tasks)); + pr_cont("\t->blkd_tasks"); + i = 0; + list_for_each(lhp, &rnp->blkd_tasks) { + pr_cont(" %p", lhp); + if (++i >= 10) + break; + } + pr_cont("\n"); +} + #else /* #ifdef CONFIG_PREEMPT_RCU */ static struct rcu_state *const rcu_state_p = &rcu_sched_state; @@ -949,6 +970,14 @@ void exit_rcu(void) { } +/* + * Dump the guaranteed-empty blocked-tasks state. Trust but verify. + */ +static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck) +{ + WARN_ON_ONCE(!list_empty(&rnp->blkd_tasks)); +} + #endif /* #else #ifdef CONFIG_PREEMPT_RCU */ #ifdef CONFIG_RCU_BOOST -- 2.5.2
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