[PATCH] Update cfq io scheduler to time sliced design

This updates the CFQ io scheduler to the new time sliced design (cfq
v3).  It provides full process fairness, while giving excellent
aggregate system throughput even for many competing processes.  It
supports io priorities, either inherited from the cpu nice value or set
directly with the ioprio_get/set syscalls.  The latter closely mimic
set/getpriority.

This import is based on my latest from -mm.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 8 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b54a0348a890..21a8674cd149 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -54,16 +54,23 @@ struct as_io_context {
 
 struct cfq_queue;
 struct cfq_io_context {
-        void (*dtor)(struct cfq_io_context *);
-        void (*exit)(struct cfq_io_context *);
-
-        struct io_context *ioc;
-
         /*
          * circular list of cfq_io_contexts belonging to a process io context
          */
         struct list_head list;
         struct cfq_queue *cfqq;
+        void *key;
+
+        struct io_context *ioc;
+
+        unsigned long last_end_request;
+        unsigned long last_queue;
+        unsigned long ttime_total;
+        unsigned long ttime_samples;
+        unsigned long ttime_mean;
+
+        void (*dtor)(struct cfq_io_context *);
+        void (*exit)(struct cfq_io_context *);
 };
 
 /*
@@ -73,7 +80,9 @@ struct cfq_io_context {
  */
 struct io_context {
         atomic_t refcount;
-        pid_t pid;
+        struct task_struct *task;
+
+        int (*set_ioprio)(struct io_context *, unsigned int);
 
         /*
          * For request batching
@@ -81,8 +90,6 @@ struct io_context {
         unsigned long last_waited; /* Time last woken after wait for request */
         int nr_batch_requests;     /* Number of requests left in the batch */
 
-        spinlock_t lock;
-
         struct as_io_context *aic;
         struct cfq_io_context *cic;
 };
@@ -134,6 +141,8 @@ struct request {
 
         void *elevator_private;
 
+        unsigned short ioprio;
+
         int rq_status;  /* should split this into a few status bits */
         struct gendisk *rq_disk;
         int errors;