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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-01-26 12:44:34 +0100
committerIngo Molnar <mingo@elte.hu>2012-01-27 13:28:48 +0100
commit39be350127ec60a078edffe5b4915dafba4ba514 (patch)
tree9b1ad6ee75c3b5842434b697b96ccdfbe1a40a2f /block
parentcb297a3e433dbdcf7ad81e0564e7b804c941ff0d (diff)
downloadlinux-linaro-stable-39be350127ec60a078edffe5b4915dafba4ba514.tar.gz
sched, block: Unify cache detection
The block layer has some code trying to determine if two CPUs share a cache, the scheduler has a similar function. Expose the function used by the scheduler and make the block layer use it, thereby removing the block layers usage of CONFIG_SCHED* and topology bits. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Jens Axboe <axboe@kernel.dk> Link: http://lkml.kernel.org/r/1327579450.2446.95.camel@twins
Diffstat (limited to 'block')
-rw-r--r--block/blk-softirq.c16
-rw-r--r--block/blk.h16
2 files changed, 8 insertions, 24 deletions
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 1366a89d8e66..467c8de88642 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -8,6 +8,7 @@
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
+#include <linux/sched.h>
#include "blk.h"
@@ -103,9 +104,10 @@ static struct notifier_block __cpuinitdata blk_cpu_notifier = {
void __blk_complete_request(struct request *req)
{
- int ccpu, cpu, group_cpu = NR_CPUS;
+ int ccpu, cpu;
struct request_queue *q = req->q;
unsigned long flags;
+ bool shared = false;
BUG_ON(!q->softirq_done_fn);
@@ -117,22 +119,20 @@ void __blk_complete_request(struct request *req)
*/
if (req->cpu != -1) {
ccpu = req->cpu;
- if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) {
- ccpu = blk_cpu_to_group(ccpu);
- group_cpu = blk_cpu_to_group(cpu);
- }
+ if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
+ shared = cpus_share_cache(cpu, ccpu);
} else
ccpu = cpu;
/*
- * If current CPU and requested CPU are in the same group, running
- * softirq in current CPU. One might concern this is just like
+ * If current CPU and requested CPU share a cache, run the softirq on
+ * the current CPU. One might concern this is just like
* QUEUE_FLAG_SAME_FORCE, but actually not. blk_complete_request() is
* running in interrupt handler, and currently I/O controller doesn't
* support multiple interrupts, so current CPU is unique actually. This
* avoids IPI sending from current CPU to the first CPU of a group.
*/
- if (ccpu == cpu || ccpu == group_cpu) {
+ if (ccpu == cpu || shared) {
struct list_head *list;
do_local:
list = &__get_cpu_var(blk_cpu_done);
diff --git a/block/blk.h b/block/blk.h
index 7efd772336de..df5b59acbdff 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -164,22 +164,6 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
return q->nr_congestion_off;
}
-static inline int blk_cpu_to_group(int cpu)
-{
- int group = NR_CPUS;
-#ifdef CONFIG_SCHED_MC
- const struct cpumask *mask = cpu_coregroup_mask(cpu);
- group = cpumask_first(mask);
-#elif defined(CONFIG_SCHED_SMT)
- group = cpumask_first(topology_thread_cpumask(cpu));
-#else
- return cpu;
-#endif
- if (likely(group < NR_CPUS))
- return group;
- return cpu;
-}
-
/*
* Contribute to IO statistics IFF:
*