From e2d74ac0664c89757bde8fb18c98cd7bf53da61c Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 28 Mar 2006 08:59:01 +0200 Subject: [PATCH] [BLOCK] cfq-iosched: change cfq io context linking from list to tree On setups with many disks, we spend a considerable amount of time looking up the process-disk mapping on each queue of io. Testing with a NULL based block driver, this costs 40-50% reduction in throughput for 1000 disks. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index c179966f1a2..ed0ffa67356 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -55,13 +55,11 @@ struct as_io_context { struct cfq_queue; struct cfq_io_context { - /* - * circular list of cfq_io_contexts belonging to a process io context - */ - struct list_head list; - struct cfq_queue *cfqq[2]; + struct rb_node rb_node; void *key; + struct cfq_queue *cfqq[2]; + struct io_context *ioc; unsigned long last_end_request; @@ -72,8 +70,8 @@ struct cfq_io_context { struct list_head queue_list; - void (*dtor)(struct cfq_io_context *); - void (*exit)(struct cfq_io_context *); + void (*dtor)(struct io_context *); /* destructor */ + void (*exit)(struct io_context *); /* called on task exit */ }; /* @@ -94,7 +92,7 @@ struct io_context { int nr_batch_requests; /* Number of requests left in the batch */ struct as_io_context *aic; - struct cfq_io_context *cic; + struct rb_root cic_root; }; void put_io_context(struct io_context *ioc); -- cgit v1.2.3