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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-09-28 18:46:33 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-10-05 23:02:04 +0400 |
| commit | a0b6c9a78c41dc36732d6e1e90f0f2f57b29816f (patch) | |
| tree | 4e68c76c95a74e1c8f3360c10e2c3496b7a7df0d /kernel/rcutree.h | |
| parent | 3d76c082907e8f83c5d5c4572f38d53ad8f00c4b (diff) | |
| download | linux-a0b6c9a78c41dc36732d6e1e90f0f2f57b29816f.tar.xz | |
rcu: Clean up code based on review feedback from Josh Triplett, part 4
These issues identified during an old-fashioned face-to-face code
review extending over many hours. This group improves an existing
abstraction and introduces two new ones. It also fixes an RCU
stall-warning bug found while making the other changes.
o Make RCU_INIT_FLAVOR() declare its own variables, removing
the need to declare them at each call site.
o Create an rcu_for_each_leaf() macro that scans the leaf
nodes of the rcu_node tree.
o Create an rcu_for_each_node_breadth_first() macro that does
a breadth-first traversal of the rcu_node tree, AKA
stepping through the array in index-number order.
o If all CPUs corresponding to a given leaf rcu_node
structure go offline, then any tasks queued on that leaf
will be moved to the root rcu_node structure. Therefore,
the stall-warning code must dump out tasks queued on the
root rcu_node structure as well as those queued on the leaf
rcu_node structures.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12541491934126-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index e6ab31cc28ba..676eecd371d9 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -106,6 +106,18 @@ struct rcu_node { /* blocked_tasks[] array. */ } ____cacheline_internodealigned_in_smp; +/* + * Do a full breadth-first scan of the rcu_node structures for the + * specified rcu_state structure. + */ +#define rcu_for_each_node_breadth_first(rsp, rnp) \ + for ((rnp) = &(rsp)->node[0]; \ + (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) + +#define rcu_for_each_leaf_node(rsp, rnp) \ + for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \ + (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) + /* Index values for nxttail array in struct rcu_data. */ #define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */ #define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */ |