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>,
fcicq@fcicq.net
Subject: Re: [PATCH] mm: print a warning once the vm dirtiness settings is illogical
Date: Mon, 27 Nov 2017 09:21:12 +0100 [thread overview]
Message-ID: <20171127082112.b7elnzy24qiqze46@dhcp22.suse.cz> (raw)
In-Reply-To: <CALOAHbCVoy=5U0_7wg9nZR+sa8buG41BAE4KDnr2Fb4tYqhaXw@mail.gmail.com>
On Mon 27-11-17 16:06:50, Yafang Shao wrote:
> +cc fcicq
[...]
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 8a15511..6c5c018 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -377,7 +377,16 @@ static unsigned long global_dirtyable_memory(void)
> if (!vm_highmem_is_dirtyable)
> x -= highmem_dirtyable_memory(x);
>
> - return x + 1; /* Ensure that we never return 0 */
> + /*
> + * - Why 100 ?
> + * - Because the return value will be used by dirty ratio and
> + * dirty background ratio to calculate dirty thresh and bg thresh,
> + * so if the return value is two small, the thresh value maybe
> + * calculated to 0.
> + * As the max value of ratio is 100, so the return value is added
> + * by 100 here.
> + */
> + return x + 100;
No. We should just revert 0f6d24f87856 ("mm/page-writeback.c: print a
warning if the vm dirtiness settings are illogical") because it is of a
dubious value and it causes problems. I am not even sure why it got
merged. It doesn't have any ack or review and I remember objecting to
the patch previously as pointless.
--
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:[~2017-11-27 8:21 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 [this message]
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
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=20171127082112.b7elnzy24qiqze46@dhcp22.suse.cz \
--to=mhocko@suse.com \
--cc=akpm@linux-foundation.org \
--cc=fcicq@fcicq.net \
--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).