Re: [PATCH 2/2] block: remove the per-bio/request write hint

Bart Van Assche
2022-03-05T23:55:55Z

On 3/5/22 13:40, Dave Chinner wrote:
> On Sat, Mar 05, 2022 at 06:19:29AM +0100, Christoph Hellwig wrote:
>> On Sat, Mar 05, 2022 at 09:12:55AM +1100, Dave Chinner wrote:
>>> AFAICT, this patch leaves just the f2fs allocator usage of
>>> inode->i_rw_hint to select a segment to allocate from as the
>>> remaining consumer of this entire plumbing and user API. Is that
>>> used by applications anywhere, or can that be removed and so the
>>> rest of the infrastructure get removed and the fcntl()s no-op'd or
>>> -EOPNOTSUPP?
>>
>> I was told it is used quite heavily in android.
>
> So it's primarily used by out of tree code? And that after this
> patch, there's really no way to test that this API does anything
> useful at all?

Hi Dave,

Android kernel developers follow the "upstream first" policy for core kernel
code (this means all kernel code other than kernel drivers that implement
support for the phone SoC). As a result, the Android 13 F2FS implementation is
very close to the upstream F2FS code. So the statement above about "out of tree
code" is not correct.

Bart.