From e6a1c874a064e7d07f24986aba7cd537b7f4a25d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 10 Aug 2006 09:00:21 +0200 Subject: [PATCH] [PATCH] struct request: shrink and optimize some more Move some members around and unionize completion_data and rb_node since they cannot ever be used at the same time. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 8a3e309e0842..a1e288069e2e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -211,6 +211,8 @@ struct request { struct list_head queuelist; struct list_head donelist; + request_queue_t *q; + unsigned int cmd_flags; enum rq_cmd_type_bits cmd_type; @@ -219,12 +221,12 @@ struct request { */ sector_t sector; /* next sector to submit */ + sector_t hard_sector; /* next sector to complete */ unsigned long nr_sectors; /* no. of sectors left to submit */ + unsigned long hard_nr_sectors; /* no. of sectors left to complete */ /* no. of sectors left to submit in the current segment */ unsigned int current_nr_sectors; - sector_t hard_sector; /* next sector to complete */ - unsigned long hard_nr_sectors; /* no. of sectors left to complete */ /* no. of sectors left to complete in the current segment */ unsigned int hard_cur_sectors; @@ -232,7 +234,15 @@ struct request { struct bio *biotail; struct hlist_node hash; /* merge hash */ - struct rb_node rb_node; /* sort/lookup */ + /* + * The rb_node is only used inside the io scheduler, requests + * are pruned when moved to the dispatch queue. So let the + * completion_data share space with the rb_node. + */ + union { + struct rb_node rb_node; /* sort/lookup */ + void *completion_data; + }; /* * two pointers are available for the IO schedulers, if they need @@ -241,8 +251,6 @@ struct request { void *elevator_private; void *elevator_private2; - void *completion_data; - struct gendisk *rq_disk; unsigned long start_time; @@ -260,8 +268,6 @@ struct request { unsigned short ioprio; - request_queue_t *q; - void *special; char *buffer;