From: Jens Axboe <axboe@kernel.dk>
To: Adam Manzanares <Adam.Manzanares@wdc.com>,
Matthew Wilcox <willy@infradead.org>
Cc: "viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"bcrl@kvack.org" <bcrl@kvack.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-aio@kvack.org" <linux-aio@kvack.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] fs: Add aio iopriority support for block_dev
Date: Thu, 3 May 2018 15:20:26 -0600 [thread overview]
Message-ID: <9e3ba3eb-9c41-3b5d-dc12-f9ef573ab53f@kernel.dk> (raw)
In-Reply-To: <e81c74fd-a4a2-80e0-476c-6ff35f158abf@wdc.com>
On 5/3/18 2:58 PM, Adam Manzanares wrote:
>
>
> On 5/3/18 1:24 PM, Jens Axboe wrote:
>> On 5/3/18 2:15 PM, Adam Manzanares wrote:
>>>
>>>
>>> On 5/3/18 11:33 AM, Matthew Wilcox wrote:
>>>> On Thu, May 03, 2018 at 11:21:14AM -0700, adam.manzanares@wdc.com wrote:
>>>>> If we want to avoid bloating struct kiocb, I suggest we turn the private field
>>>>> into a union of the private and ki_ioprio field. It seems like the users of
>>>>> the private field all use it at a point where we can yank the priority from
>>>>> the kiocb before the private field is used. Comments and suggestions welcome.
>>>>
>>>> Or we could just make ki_hint a u8 or u16 ... seems unlikely we'll need
>>>> 32 bits of ki_hint. (currently defined values are 1-5)
>>>
>>> I like the approach of using a u16 for the ki_hint. I'll update and
>>> resubmit.
>>
>> It's intended to be a mask. If you do shrink it for now, then we need some
>> guard code to ensure it can always carry what it needs to.
>>
>
> Got it, I'll add the guard to rw_hint_valid along with a comment about
> being limited by the size of ki_hint in case we get to a situation where
> 16 bits is not enough.
Other way around - the API should not be limited by the fact that some
smaller type was chosen for an internal structure. Hence the guard/check
should not be in rw_hint_valid, but rather around where you assign
ki_hint. If/when we do extend the read/write hints, then we'll
potentially need to bump ki_hint to accommodate it.
--
Jens Axboe
next prev parent reply other threads:[~2018-05-03 21:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-03 18:21 [PATCH v2] fs: Add aio iopriority support for block_dev adam.manzanares
2018-05-03 18:33 ` Matthew Wilcox
2018-05-03 20:15 ` Adam Manzanares
2018-05-03 20:24 ` Jens Axboe
2018-05-03 20:58 ` Adam Manzanares
2018-05-03 21:20 ` Jens Axboe [this message]
2018-05-03 22:43 ` Matthew Wilcox
2018-05-03 22:53 ` Jens Axboe
2018-05-03 18:36 ` Jeff Moyer
2018-05-03 20:24 ` Adam Manzanares
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9e3ba3eb-9c41-3b5d-dc12-f9ef573ab53f@kernel.dk \
--to=axboe@kernel.dk \
--cc=Adam.Manzanares@wdc.com \
--cc=bcrl@kvack.org \
--cc=linux-aio@kvack.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).