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author | Paul E. McKenney <paulmck@kernel.org> | 2022-05-16 17:56:16 -0700 |
---|---|---|
committer | Paul E. McKenney <paulmck@kernel.org> | 2022-06-20 09:22:28 -0700 |
commit | 434c9eefb959c36331a93617ea95df903469b99f (patch) | |
tree | 4ca98f3c279c7595a906f3a8b9f8e315befd418c | |
parent | f90f19da88bfe32dd1fdfd104de4c0526a3be701 (diff) | |
download | linux-stable-434c9eefb959c36331a93617ea95df903469b99f.tar.gz linux-stable-434c9eefb959c36331a93617ea95df903469b99f.tar.bz2 linux-stable-434c9eefb959c36331a93617ea95df903469b99f.zip |
rcu-tasks: Add data structures for lightweight grace periods
This commit adds fields to task_struct and to rcu_tasks_percpu that will
be used to avoid the task-list scan for RCU Tasks Trace grace periods,
and also initializes these fields.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: KP Singh <kpsingh@kernel.org>
-rw-r--r-- | include/linux/sched.h | 2 | ||||
-rw-r--r-- | init/init_task.c | 1 | ||||
-rw-r--r-- | kernel/fork.c | 1 | ||||
-rw-r--r-- | kernel/rcu/tasks.h | 4 |
4 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index e6eb5871593e..b88caf54e168 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -844,6 +844,8 @@ struct task_struct { int trc_ipi_to_cpu; union rcu_special trc_reader_special; struct list_head trc_holdout_list; + struct list_head trc_blkd_node; + int trc_blkd_cpu; #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ struct sched_info sched_info; diff --git a/init/init_task.c b/init/init_task.c index 73cc8f03511a..ff6c4b9bfe6b 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -157,6 +157,7 @@ struct task_struct init_task .trc_reader_nesting = 0, .trc_reader_special.s = 0, .trc_holdout_list = LIST_HEAD_INIT(init_task.trc_holdout_list), + .trc_blkd_node = LIST_HEAD_INIT(init_task.trc_blkd_node), #endif #ifdef CONFIG_CPUSETS .mems_allowed_seq = SEQCNT_SPINLOCK_ZERO(init_task.mems_allowed_seq, diff --git a/kernel/fork.c b/kernel/fork.c index 9d44f2d46c69..1950eb870244 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1814,6 +1814,7 @@ static inline void rcu_copy_process(struct task_struct *p) p->trc_reader_nesting = 0; p->trc_reader_special.s = 0; INIT_LIST_HEAD(&p->trc_holdout_list); + INIT_LIST_HEAD(&p->trc_blkd_node); #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ } diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 64eb4d7b142e..fd4508af055e 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -29,6 +29,7 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp); * @rtp_work: Work queue for invoking callbacks. * @rtp_irq_work: IRQ work queue for deferred wakeups. * @barrier_q_head: RCU callback for barrier operation. + * @rtp_blkd_tasks: List of tasks blocked as readers. * @cpu: CPU number corresponding to this entry. * @rtpp: Pointer to the rcu_tasks structure. */ @@ -40,6 +41,7 @@ struct rcu_tasks_percpu { struct work_struct rtp_work; struct irq_work rtp_irq_work; struct rcu_head barrier_q_head; + struct list_head rtp_blkd_tasks; int cpu; struct rcu_tasks *rtpp; }; @@ -256,6 +258,8 @@ static void cblist_init_generic(struct rcu_tasks *rtp) INIT_WORK(&rtpcp->rtp_work, rcu_tasks_invoke_cbs_wq); rtpcp->cpu = cpu; rtpcp->rtpp = rtp; + if (!rtpcp->rtp_blkd_tasks.next) + INIT_LIST_HEAD(&rtpcp->rtp_blkd_tasks); raw_spin_unlock_rcu_node(rtpcp); // irqs remain disabled. } raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags); |