From: Yafang Shao <laoar.shao@gmail.com>
To: Michal Hocko <mhocko@suse.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 14:12:15 +0800 [thread overview]
Message-ID: <CALOAHbCzLYRp8G6H58vfiEJZQDxhcRx5=LqMsDc7rPQ4Erg=1w@mail.gmail.com> (raw)
In-Reply-To: <CALOAHbDNbFs51mW0kUFXcqqyJy+ydpHPaRbvquPVrPTY5HGeRg@mail.gmail.com>
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;
--
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next prev parent reply other threads:[~2017-11-28 6:12 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 [this message]
2017-11-28 7:45 ` Michal Hocko
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
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