Re: [PATCH v2 6/6] block, fs: Restore the per-bio/request data lifetime fields

Bart Van Assche <bvanassche@xxxxxxx> · Mon, 5 Feb 2024 12:46:38 -0800

On 2/2/24 12:39, Bart Van Assche wrote:
Restore support for passing data lifetime information from filesystems to
block drivers. This patch reverts commit b179c98f7697 ("block: Remove
request.write_hint") and commit c75e707fe1aa ("block: remove the
per-bio/request write hint").

This patch does not modify the size of struct bio because the new
bi_write_hint member fills a hole in struct bio. pahole reports the
following for struct bio on an x86_64 system with this patch applied:

         /* size: 112, cachelines: 2, members: 20 */
         /* sum members: 110, holes: 1, sum holes: 2 */
         /* last cacheline: 48 bytes */

Hi Jens,

Since this patch affects both the block layer and VFS code, can you please
help with reviewing this patch?

Thanks,

Bart.