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From: Zhaoyang Huang <huangzhaoyang@gmail.com>
Date: Thu, 1 Feb 2024 12:05:23 +0800
Message-ID: <CAGWkznEv=A1AOe=xGWvNnaUq2eAfrHy2TQFyScNyu9rqQ+Q6xA@mail.gmail.com>
Subject: Re: [PATCHv6 1/1] block: introduce content activity based ioprio
To: Matthew Wilcox <willy@infradead.org>
Cc: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>, Andrew Morton <akpm@linux-foundation.org>, 
	Jens Axboe <axboe@kernel.dk>, Yu Zhao <yuzhao@google.com>, Damien Le Moal <dlemoal@kernel.org>, 
	Niklas Cassel <niklas.cassel@wdc.com>, "Martin K . Petersen" <martin.petersen@oracle.com>, 
	Hannes Reinecke <hare@suse.de>, Linus Walleij <linus.walleij@linaro.org>, linux-mm@kvack.org, 
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, 
	linux-kernel@vger.kernel.org, steve.kang@unisoc.com
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On Thu, Feb 1, 2024 at 10:39=E2=80=AFAM Zhaoyang Huang <huangzhaoyang@gmail=
com> wrote:
>
> On Wed, Jan 31, 2024 at 9:23=E2=80=AFPM Matthew Wilcox <willy@infradead.o=
rg> wrote:
> >
> > On Wed, Jan 31, 2024 at 06:59:12PM +0800, zhaoyang.huang wrote:
> > > change of v6: replace the macro of bio_add_xxx by submit_bio which
> > >               iterating the bio_vec before launching bio to block lay=
er
> >
> > Still wrong.
> I did some research on bio operations in the system and state my
> understanding here. I would like to have you review it and give me
> more details of the fault. thanks
>
> 1. REQ_OP_ZONE_xxx
> a. These operations are from driver/block layer/fs where we can keep
> driver/block layer using the legacy submit_bio by not including
> act_prio.h.
> b. most of fs's REQ_OP_ZONE_xxx will be handled by blkdev_zone_mgmt
> which is the same as 'a'
> c. __submit_zone_reset_cmd within f2fs use no page for REQ_OP_ZONE_RESET
>
> 2. other REQ_OP_<none>_READ/WRITE except REQ_OP_ZONE_xxx
> These operations all comes from driver and block layer as same as 1.a
>
> 3. direct_io
> keep fs/direct-io.c and fs/iomap/direct-io.c using legacy submit_bio
>
> 4. metadata, dentry
> Are these data also file pages?
>
> 5. normal REQ_OP_READ/WRITE/SYNC
> fs choose to use act based submit_bio by including act_ioprio.h in
> corresponding c file

OR could I restrict the change by judging bio_op as below

+ if (bio_op(bio) =3D=3D REQ_OP_READ || bio_op(bio) =3D=3D REQ_OP_WRITE)
+ {
       class =3D IOPRIO_PRIO_CLASS(bio->bi_ioprio);
       level =3D IOPRIO_PRIO_LEVEL(bio->bi_ioprio);
       hint =3D IOPRIO_PRIO_HINT(bio->bi_ioprio);
       bio_for_each_bvec(bv, bio, iter) {
               page =3D bv.bv_page;
               activity +=3D PageWorkingset(page) ? 1 : 0;
               cnt++;
       }
       if (activity >=3D cnt / 2)
               class =3D IOPRIO_CLASS_RT;
       else if (activity >=3D cnt / 4)
               class =3D max(IOPRIO_PRIO_CLASS(get_current_ioprio()),
IOPRIO_CLASS_BE);
       bio->bi_ioprio =3D IOPRIO_PRIO_VALUE_HINT(class, level, hint);
+ }
       submit_bio(bio);