From: Matthew Wilcox <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "zhaoyang.huang" <zhaoyang.huang@unisoc.com>,
Minchan Kim <minchan@kernel.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Zhaoyang Huang <huangzhaoyang@gmail.com>,
ke.wang@unisoc.com
Subject: Re: [PATCH] mm: fix printk format within cma
Date: Fri, 28 Apr 2023 15:35:10 +0100 [thread overview]
Message-ID: <ZEvZnvIx5mbnIzsx@casper.infradead.org> (raw)
In-Reply-To: <20230418123338.3b85a013cf6ce1fcb3677ae2@linux-foundation.org>
On Tue, Apr 18, 2023 at 12:33:38PM -0700, Andrew Morton wrote:
> On Tue, 18 Apr 2023 04:38:24 +0100 Matthew Wilcox <willy@infradead.org> wrote:
>
> > On Tue, Apr 18, 2023 at 11:33:09AM +0800, zhaoyang.huang wrote:
> > > cma and page pointer printed via %p are hash value which make debug to be hard.
> > > change them to %px.
> >
> > Why does printing the page pointer make any sense at all? Surely the
> > PFN makes much more sense.
>
> I suppose one could correlate a particular hashed pointer with other
> debug output, see "ah, that's the same page". In which case one
> doesn't really care whether or not the address is hashed - it's just a
> cookie. This sounds thin.
>
> I doubt if a lot of thought went into the printk. If the page pointer
> isn't useful then how about we simply remove it from the message?
If something about it weren't useful, I don't think we'd be seeing a patch
to transform it from a hashed pointer to an unhashed pointer? I'm pretty
sure the PFN is the real information that's wanted here, since you can
look at the hardware RAM layout to determine why that's not eligible.
prev parent reply other threads:[~2023-04-28 14:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-18 3:33 zhaoyang.huang
2023-04-18 3:38 ` Matthew Wilcox
2023-04-18 4:16 ` Zhaoyang Huang
2023-04-18 5:24 ` Huang, Ying
2023-04-18 19:33 ` Andrew Morton
2023-04-28 14:35 ` Matthew Wilcox [this message]
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=ZEvZnvIx5mbnIzsx@casper.infradead.org \
--to=willy@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=huangzhaoyang@gmail.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=ke.wang@unisoc.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=minchan@kernel.org \
--cc=zhaoyang.huang@unisoc.com \
/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