From 87192a2a49c475cf322cb143e0fa63b0102d8567 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 12 Jan 2012 17:20:34 -0800 Subject: [PATCH] vfs: cache request_queue in struct block_device This makes it possible to get from the inode to the request_queue with one less cache miss. Used in followon optimization. The livetime of the pointer is the same as the gendisk. This assumes that the queue will always stay the same in the gendisk while it's visible to block_devices. I think that's safe correct? Signed-off-by: Andi Kleen Acked-by: Jeff Moyer Cc: Jens Axboe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/block_dev.c | 3 +++ include/linux/fs.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/fs/block_dev.c b/fs/block_dev.c index afe74dda632b..0e575d1304b4 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1139,6 +1139,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) mutex_lock_nested(&bdev->bd_mutex, for_part); if (!bdev->bd_openers) { bdev->bd_disk = disk; + bdev->bd_queue = disk->queue; bdev->bd_contains = bdev; if (!partno) { struct backing_dev_info *bdi; @@ -1159,6 +1160,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) disk_put_part(bdev->bd_part); bdev->bd_part = NULL; bdev->bd_disk = NULL; + bdev->bd_queue = NULL; mutex_unlock(&bdev->bd_mutex); disk_unblock_events(disk); put_disk(disk); @@ -1232,6 +1234,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) disk_put_part(bdev->bd_part); bdev->bd_disk = NULL; bdev->bd_part = NULL; + bdev->bd_queue = NULL; bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info); if (bdev != bdev->bd_contains) __blkdev_put(bdev->bd_contains, mode, 1); diff --git a/include/linux/fs.h b/include/linux/fs.h index e694bd4434a4..4bc8169fb5a1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -660,6 +660,7 @@ struct address_space { * must be enforced here for CRIS, to let the least significant bit * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON. */ +struct request_queue; struct block_device { dev_t bd_dev; /* not a kdev_t - it's a search key */ @@ -682,6 +683,7 @@ struct block_device { unsigned bd_part_count; int bd_invalidated; struct gendisk * bd_disk; + struct request_queue * bd_queue; struct list_head bd_list; /* * Private data. You must have bd_claim'ed the block_device -- GitLab