From: Michal Hocko <mhocko@suse.com>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH] Revert "mm/page-writeback.c: print a warning if the vm dirtiness settings are illogical" (was: Re: [PATCH] mm: print a warning once the vm dirtiness settings is illogical)
Date: Tue, 28 Nov 2017 08:45:06 +0100 [thread overview]
Message-ID: <20171128074506.bw5r2wzt3pooyu22@dhcp22.suse.cz> (raw)
In-Reply-To: <CALOAHbCzLYRp8G6H58vfiEJZQDxhcRx5=LqMsDc7rPQ4Erg=1w@mail.gmail.com>
On Tue 28-11-17 14:12:15, Yafang Shao wrote:
> 2017-11-28 11:11 GMT+08:00 Yafang Shao <laoar.shao@gmail.com>:
> > Hi Michal,
> >
> > What about bellow change ?
> > It makes the function domain_dirty_limits() more clear.
> > And the result will have a higher precision.
> >
> >
> > diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> > index 8a15511..2b5e507 100644
> > --- a/mm/page-writeback.c
> > +++ b/mm/page-writeback.c
> > @@ -397,8 +397,8 @@ static void domain_dirty_limits(struct
> > dirty_throttle_control *dtc)
> > unsigned long bytes = vm_dirty_bytes;
> > unsigned long bg_bytes = dirty_background_bytes;
> > /* convert ratios to per-PAGE_SIZE for higher precision */
> > - unsigned long ratio = (vm_dirty_ratio * PAGE_SIZE) / 100;
> > - unsigned long bg_ratio = (dirty_background_ratio * PAGE_SIZE) / 100;
> > + unsigned long ratio = vm_dirty_ratio;
> > + unsigned long bg_ratio = dirty_background_ratio;
> > unsigned long thresh;
> > unsigned long bg_thresh;
> > struct task_struct *tsk;
> > @@ -416,28 +416,33 @@ static void domain_dirty_limits(struct
> > dirty_throttle_control *dtc)
> > */
> > if (bytes)
> > ratio = min(DIV_ROUND_UP(bytes, global_avail),
> > - PAGE_SIZE);
> > + 100);
> > if (bg_bytes)
> > bg_ratio = min(DIV_ROUND_UP(bg_bytes, global_avail),
> > - PAGE_SIZE);
> > + 99); /* bg_ratio should less than ratio */
> > bytes = bg_bytes = 0;
> > }
>
>
> Errata:
>
> if (bytes)
> - ratio = min(DIV_ROUND_UP(bytes, global_avail),
> - PAGE_SIZE);
> + ratio = min(DIV_ROUND_UP(bytes / PAGE_SIZE, global_avail),
> + 100);
> if (bg_bytes)
> - bg_ratio = min(DIV_ROUND_UP(bg_bytes, global_avail),
> - PAGE_SIZE);
> + bg_ratio = min(DIV_ROUND_UP(bg_bytes / PAGE_SIZE, global_avail),
> + 100 - 1); /* bg_ratio should be less than ratio */
> bytes = bg_bytes = 0;
And you really think this makes code easier to follow? I am somehow not
conviced...
--
Michal Hocko
SUSE Labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-11-28 7:45 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 9:54 [PATCH] mm: print a warning once the vm dirtiness settings is illogical Yafang Shao
2017-11-25 16:05 ` Tetsuo Handa
2017-11-26 2:24 ` Yafang Shao
2017-11-26 2:42 ` Tetsuo Handa
2017-11-26 4:32 ` Yafang Shao
2017-11-26 8:03 ` Tetsuo Handa
2017-11-26 8:27 ` Yafang Shao
2017-11-26 8:46 ` Yafang Shao
2017-11-26 10:38 ` Tetsuo Handa
2017-11-27 8:06 ` Yafang Shao
2017-11-27 8:21 ` Michal Hocko
2017-11-27 8:29 ` Yafang Shao
2017-11-27 8:32 ` Yafang Shao
2017-11-27 8:37 ` Michal Hocko
2017-11-27 8:49 ` Yafang Shao
2017-11-27 8:52 ` Michal Hocko
2017-11-27 8:54 ` Yafang Shao
2017-11-27 9:04 ` Michal Hocko
2017-11-27 9:08 ` Yafang Shao
2017-11-27 8:34 ` Michal Hocko
2017-11-27 9:19 ` [PATCH] Revert "mm/page-writeback.c: print a warning if the vm dirtiness settings are illogical" (was: Re: [PATCH] mm: print a warning once the vm dirtiness settings is illogical) Michal Hocko
2017-11-28 3:11 ` Yafang Shao
2017-11-28 6:12 ` Yafang Shao
2017-11-28 7:45 ` Michal Hocko [this message]
2017-11-28 7:52 ` Yafang Shao
2017-11-28 9:43 ` Yafang Shao
2017-11-28 9:45 ` Michal Hocko
2017-11-28 10:09 ` Jan Kara
2017-11-28 10:16 ` Yafang Shao
2017-11-28 10:25 ` Jan Kara
2017-11-28 10:33 ` Yafang Shao
2017-11-28 10:41 ` Jan Kara
2017-11-28 10:44 ` Yafang Shao
2017-11-28 10:37 ` Jan Kara
2017-11-28 10:48 ` Michal Hocko
2017-11-28 11:05 ` Yafang Shao
2017-11-28 11:54 ` Michal Hocko
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=20171128074506.bw5r2wzt3pooyu22@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=akpm@linux-foundation.org \
--cc=jack@suse.cz \
--cc=laoar.shao@gmail.com \
--cc=linux-mm@kvack.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
/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).