diff options
Diffstat (limited to 'block/blk-settings.c')
| -rw-r--r-- | block/blk-settings.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 5ea3de48afba..4f6eb4bb1723 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -372,6 +372,19 @@ void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) } EXPORT_SYMBOL(blk_queue_alignment_offset); +void blk_queue_update_readahead(struct request_queue *q) +{ + /* + * For read-ahead of large files to be effective, we need to read ahead + * at least twice the optimal I/O size. + */ + q->backing_dev_info->ra_pages = + max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES); + q->backing_dev_info->io_pages = + queue_max_sectors(q) >> (PAGE_SHIFT - 9); +} +EXPORT_SYMBOL_GPL(blk_queue_update_readahead); + /** * blk_limits_io_min - set minimum request size for a device * @limits: the queue limits @@ -450,6 +463,8 @@ EXPORT_SYMBOL(blk_limits_io_opt); void blk_queue_io_opt(struct request_queue *q, unsigned int opt) { blk_limits_io_opt(&q->limits, opt); + q->backing_dev_info->ra_pages = + max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES); } EXPORT_SYMBOL(blk_queue_io_opt); @@ -631,8 +646,7 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, top, bottom); } - t->backing_dev_info->io_pages = - t->limits.max_sectors >> (PAGE_SHIFT - 9); + blk_queue_update_readahead(disk->queue); } EXPORT_SYMBOL(disk_stack_limits); |