powerpc: Use set_cpus_allowed_ptr

[safe/jmp/linux-2.6] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f27e535..fc98a48 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -7,6 +7,7 @@
  *  Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
  */
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/blkdev.h>
 #include <linux/elevator.h>
 #include <linux/jiffies.h>
@@ -19,7 +20,7 @@
  * tunables
  */
 /* max queue in one round of service */
-static const int cfq_quantum = 4;
+static const int cfq_quantum = 8;
 static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
 /* maximum backwards seek, in KiB */
 static const int cfq_back_max = 16 * 1024;
@@ -78,11 +79,12 @@ struct cfq_rb_root {
        struct rb_root rb;
        struct rb_node *left;
        unsigned count;
+       unsigned total_weight;
        u64 min_vdisktime;
        struct rb_node *active;
-       unsigned total_weight;
 };
-#define CFQ_RB_ROOT    (struct cfq_rb_root) { RB_ROOT, NULL, 0, 0, }
+#define CFQ_RB_ROOT    (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
+                       .count = 0, .min_vdisktime = 0, }
 
 /*
  * Per process-grouping structure
@@ -2197,6 +2199,19 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
        return dispatched;
 }
 
+static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
+       struct cfq_queue *cfqq)
+{
+       /* the queue hasn't finished any request, can't estimate */
+       if (cfq_cfqq_slice_new(cfqq))
+               return 1;
+       if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched,
+               cfqq->slice_end))
+               return 1;
+
+       return 0;
+}
+
 static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
        unsigned int max_dispatch;
@@ -2213,7 +2228,7 @@ static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
        if (cfqd->rq_in_flight[BLK_RW_SYNC] && !cfq_cfqq_sync(cfqq))
                return false;
 
-       max_dispatch = cfqd->cfq_quantum;
+       max_dispatch = max_t(unsigned int, cfqd->cfq_quantum / 2, 1);
        if (cfq_class_idle(cfqq))
                max_dispatch = 1;
 
@@ -2230,13 +2245,22 @@ static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
                /*
                 * We have other queues, don't allow more IO from this one
                 */
-               if (cfqd->busy_queues > 1)
+               if (cfqd->busy_queues > 1 && cfq_slice_used_soon(cfqd, cfqq))
                        return false;
 
                /*
                 * Sole queue user, no limit
                 */
-               max_dispatch = -1;
+               if (cfqd->busy_queues == 1)
+                       max_dispatch = -1;
+               else
+                       /*
+                        * Normally we start throttling cfqq when cfq_quantum/2
+                        * requests have been dispatched. But we can drive
+                        * deeper queue depths at the beginning of slice
+                        * subjected to upper limit of cfq_quantum.
+                        * */
+                       max_dispatch = cfqd->cfq_quantum;
        }
 
        /*