Hi,
在 2023/11/21 18:11, Ming Lei 写道:
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.
This patch looks good, do you want me do take it for a v3 for the
other patchset?
And by the way, can we also move 'int bd_writers' to near 'atomic_t
bd_fsfreeze_count' to save 8 bytes(int 64bit platform)?
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 07abd0165226..a47ab9249bdd 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -63,11 +63,11 @@ struct block_device {
int bd_holders;
struct kobject *bd_holder_dir;
+ int bd_writers;
atomic_t bd_fsfreeze_count; /* number of freeze
requests */
struct mutex bd_fsfreeze_mutex; /* serialize
freeze/thaw */
struct partition_meta_info *bd_meta_info;
- int bd_writers;
Thanks,
Kuai
Cc: Yu Kuai <yukuai3@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
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 */
+
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;
