Re: [PATCH v1 net] page_pool: Cap queue size to 32k.

Dan Carpenter
2023-09-05T16:51:09Z

On Mon, Aug 14, 2023 at 11:34:11AM +0530, Ratheesh Kannoth wrote:
> Clamp to 32k instead of returning error.

What is the motivation here? What is the real world impact for the
users?

>
> Please find discussion at
> https://lore.kernel.org/lkml/
> CY4PR1801MB1911E15D518A77535F6E51E2D308A@CY4PR1801MB1911.
> namprd18.prod.outlook.com/T/

Please don't break the URL up like this. I think normally we would just
write up a normal commit message and use the Link: tag.

Fixes: ff7d6b27f894 ("page_pool: refurbish version of page_pool code")
Link: https://lore.kernel.org/lkml/CY4PR1801MB1911E15D518A77535F6E51E2D308A@CY4PR1801MB1911.namprd18.prod.outlook.com/
Signed-off-by:

> @@ -171,9 +171,10 @@ static int page_pool_init(struct page_pool *pool,
> if (pool->p.pool_size)
> ring_qsize = pool->p.pool_size;
>
> - /* Sanity limit mem that can be pinned down */
> + /* Cap queue size to 32k */
> if (ring_qsize > 32768)
> - return -E2BIG;
> + ring_qsize = 32768;
> +
>
> /* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.

Don't introduce a blank line here. Checkpatch will complain if you
have to blank lines in a row. It won't complain about the patch but it
will complain if you apply the patch and then re-run checkpatch -f on
the file. (I didn't test this but it's wrong either way. :P).

regards,
dan carpenter