padata: simplify serialization mechanism
We count the number of processed objects on a percpu basis,
so we need to go through all the percpu reorder queues to calculate
the sequence number of the next object that needs serialization.
This patch changes this to count the number of processed objects
global. So we can calculate the sequence number and the percpu
reorder queue of the next object that needs serialization without
searching through the percpu reorder queues. This avoids some
accesses to memory of foreign cpus.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/linux/padata.h b/include/linux/padata.h
index e4c17f9..8844b85 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -67,7 +67,6 @@
* @pwork: work struct for parallelization.
* @swork: work struct for serialization.
* @pd: Backpointer to the internal control structure.
- * @num_obj: Number of objects that are processed by this cpu.
* @cpu_index: Index of the cpu.
*/
struct padata_queue {
@@ -77,7 +76,6 @@
struct work_struct pwork;
struct work_struct swork;
struct parallel_data *pd;
- atomic_t num_obj;
int cpu_index;
};
@@ -93,6 +91,7 @@
* @max_seq_nr: Maximal used sequence number.
* @cpumask: cpumask in use.
* @lock: Reorder lock.
+ * @processed: Number of already processed objects.
* @timer: Reorder timer.
*/
struct parallel_data {
@@ -103,7 +102,8 @@
atomic_t refcnt;
unsigned int max_seq_nr;
cpumask_var_t cpumask;
- spinlock_t lock;
+ spinlock_t lock ____cacheline_aligned;
+ unsigned int processed;
struct timer_list timer;
};