lkml.org 
[lkml]   [2020]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 tip/core/rcu 30/34] rcu-tasks: Make RCU tasks trace also wait for idle tasks
    Date
    From: "Paul E. McKenney" <paulmck@kernel.org>

    This commit scans the CPUs, adding each CPU's idle task to the list of
    tasks that need quiescent states.

    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
    ---
    kernel/rcu/tasks.h | 18 +++++++++++++-----
    1 file changed, 13 insertions(+), 5 deletions(-)

    diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
    index d1fa7715..27d2458 100644
    --- a/kernel/rcu/tasks.h
    +++ b/kernel/rcu/tasks.h
    @@ -15,7 +15,7 @@ struct rcu_tasks;
    typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);
    typedef void (*pregp_func_t)(void);
    typedef void (*pertask_func_t)(struct task_struct *t, struct list_head *hop);
    -typedef void (*postscan_func_t)(void);
    +typedef void (*postscan_func_t)(struct list_head *hop);
    typedef void (*holdouts_func_t)(struct list_head *hop, bool ndrpt, bool *frptp);
    typedef void (*postgp_func_t)(struct rcu_tasks *rtp);

    @@ -331,7 +331,7 @@ static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)
    rcu_read_unlock();

    set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);
    - rtp->postscan_func();
    + rtp->postscan_func(&holdouts);

    /*
    * Each pass through the following loop scans the list of holdout
    @@ -415,7 +415,7 @@ static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop)
    }

    /* Processing between scanning taskslist and draining the holdout list. */
    -void rcu_tasks_postscan(void)
    +void rcu_tasks_postscan(struct list_head *hop)
    {
    /*
    * Wait for tasks that are in the process of exiting. This
    @@ -932,9 +932,17 @@ static void rcu_tasks_trace_pertask(struct task_struct *t,
    trc_wait_for_one_reader(t, hop);
    }

    -/* Do intermediate processing between task and holdout scans. */
    -static void rcu_tasks_trace_postscan(void)
    +/*
    + * Do intermediate processing between task and holdout scans and
    + * pick up the idle tasks.
    + */
    +static void rcu_tasks_trace_postscan(struct list_head *hop)
    {
    + int cpu;
    +
    + for_each_possible_cpu(cpu)
    + rcu_tasks_trace_pertask(idle_task(cpu), hop);
    +
    // Re-enable CPU hotplug now that the tasklist scan has completed.
    cpus_read_unlock();

    --
    2.9.5
    \
     
     \ /
      Last update: 2020-03-27 23:41    [W:4.239 / U:0.704 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site