Re: [PATCH] block: respect virtual boundary mask in bvecs

[Johannes Thumshirn]

On 05/11/2018 13:01, Ming Lei wrote:
> If you mean the real huge page, this patch shouldn't have made a difference
> because bio_vec->bv_offset is in [0, PAGE_SIZE), and iSer sets virt
> boundary as 4K - 1.
> 
> However, things will change after multipage bvec is introduced.


Hi Ming,

I've received a blktrace from our customer showing the issue [1].

In this example trace they've submitted (contiguous) 64K I/Os and
without this patch, they're seeing a lot of splits as indicated by the
trace.

With the patch applied the I/O is directly issued to the LLDD without
the splits.

[1] http://beta.suse.com/private/jthumshirn/blktrace.txt

Byte,
	Johannes
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