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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2010-11-29 21:56:39 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-05-05 23:16:54 -0700 |
| commit | 12f5f524cafef3ab689929b118f2dfb8bf2be321 (patch) | |
| tree | 639473556b6edf9b79e0a18d5ba58f80eea76519 /kernel/rcutree.h | |
| parent | e59fb3120becfb36b22ddb8bd27d065d3cdca499 (diff) | |
| download | linux-12f5f524cafef3ab689929b118f2dfb8bf2be321.tar.gz linux-12f5f524cafef3ab689929b118f2dfb8bf2be321.tar.bz2 linux-12f5f524cafef3ab689929b118f2dfb8bf2be321.zip | |
rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the
rcu_node structure into a single ->blkd_tasks list with ->gp_tasks
and ->exp_tasks tail pointers. This is in preparation for RCU priority
boosting, which will add a third dimension to the combinatorial explosion
in the ->blocked_tasks[] case, but simply a third pointer in the new
->blkd_tasks case.
Also update documentation to reflect blocked_tasks[] merge
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index bd891def3303..5a439c180e69 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -107,7 +107,7 @@ struct rcu_node { /* an rcu_data structure, otherwise, each */ /* bit corresponds to a child rcu_node */ /* structure. */ - unsigned long expmask; /* Groups that have ->blocked_tasks[] */ + unsigned long expmask; /* Groups that have ->blkd_tasks */ /* elements that need to drain to allow the */ /* current expedited grace period to */ /* complete (only for TREE_PREEMPT_RCU). */ @@ -120,11 +120,20 @@ struct rcu_node { u8 grpnum; /* CPU/group number for next level up. */ u8 level; /* root is at level 0. */ struct rcu_node *parent; - struct list_head blocked_tasks[4]; - /* Tasks blocked in RCU read-side critsect. */ - /* Grace period number (->gpnum) x blocked */ - /* by tasks on the (x & 0x1) element of the */ - /* blocked_tasks[] array. */ + struct list_head blkd_tasks; + /* Tasks blocked in RCU read-side critical */ + /* section. Tasks are placed at the head */ + /* of this list and age towards the tail. */ + struct list_head *gp_tasks; + /* Pointer to the first task blocking the */ + /* current grace period, or NULL if there */ + /* is no such task. */ + struct list_head *exp_tasks; + /* Pointer to the first task blocking the */ + /* current expedited grace period, or NULL */ + /* if there is no such task. If there */ + /* is no current expedited grace period, */ + /* then there can cannot be any such task. */ } ____cacheline_internodealigned_in_smp; /* |