Messages in this thread | | | Subject | Re: [PATCH v3 1/3] block: move .bd_inode into 1st cacheline of block_device | From | Yu Kuai <> | Date | Wed, 22 Nov 2023 19:17:31 +0800 |
| |
Hi,
在 2023/11/22 18:31, Yu Kuai 写道: > From: Ming Lei <ming.lei@redhat.com> > > The .bd_inode field of block_device is used in IO fast path of > blkdev_write_iter() and blkdev_llseek(), so it is more efficient to keep > it into the 1st cacheline. > > .bd_openers is only touched in open()/close(), and .bd_size_lock is only > for updating bdev capacity, which is in slow path too. > > So swap .bd_inode layout with .bd_openers & .bd_size_lock to move > .bd_inode into the 1st cache line. > > Cc: Yu Kuai <yukuai3@huawei.com> > Signed-off-by: Ming Lei <ming.lei@redhat.com> > Signed-off-by: Yu Kuai <yukuai3@huawei.com> > --- > include/linux/blk_types.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index d5c5e59ddbd2..f7d40692dd94 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -49,9 +49,10 @@ struct block_device { > bool bd_write_holder; > bool bd_has_submit_bio; > dev_t bd_dev; > + struct inode *bd_inode; /* will die */
Now that we're here, and bdev->bd_inode is always point to the field inode of struct bdev_inode, which is next to the field bdev, and the comment "will die" have been exist for a long time.
Maybe I can try to replace all the reference of bdev->bd_inode with a helper, and then remove this field, then it'll be acceptable to add a new field "unsigned long bd_flags".
Thanks, Kuai
> + > atomic_t bd_openers; > spinlock_t bd_size_lock; /* for bd_inode->i_size updates */ > - struct inode * bd_inode; /* will die */ > void * bd_claiming; > void * bd_holder; > const struct blk_holder_ops *bd_holder_ops; >
| |