On Tue, Jun 2, 2020 at 4:47 AM Artur Paszkiewicz
[off-list ref] wrote:

On 6/2/20 8:48 AM, Song Liu wrote:

quoted

quoted

+               clone = bio_clone_fast(bio, GFP_NOIO, &mddev->md_io_bs);

Handle clone == NULL?

I think this should never fail - bio_alloc_bioset() guarantees that. It
is used in a similar manner in raid1 and raid10. How about
BUG_ON(clone == NULL)?

I misread the code. Current version is fine.

quoted

Also, have you done benchmarks with this change?

I tested 4k random reads on a raid0 (4x P4510 2TB) and it was 2550k vs
2567k IOPS, that's slower only by about 0.66%:

Thanks for the test. I will do some more tests and process the patch
after the merge
window.

Song