Re: [PATCH 1/2] dm-bufio: improve the performance of __dm_bufio_prefetch

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Apr 02, 2025 at 03:09:34PM +0800, LongPing Wei wrote:
> 1. call blk_flush_plug when cache hit as the address of the subsequent
>  bio is no longer contiguous with the previous bio;
> 2. skip cond_resched when ioprio class is rt;
> 
> Signed-off-by: LongPing Wei <weilongping@oppo.com>
> ---
>  drivers/md/dm-bufio.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Looks fine:

Reviewed-by: Eric Biggers <ebiggers@kernel.org>

But I do think the prefetching should be reworked to be along the lines of what
I suggested here:
https://lore.kernel.org/dm-devel/20250327170524.GF1425@sol.localdomain/
Any chance you're interested in helping with that?

It also *might* be the case that the prefetching is no longer helpful and should
just be removed.  Especially if dm-verity will start prefetching the whole hash
tree anyway, as your other patch does.

- Eric