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References: <20210208101439.55474-1-laoar.shao@gmail.com> <20210208122009.GN308988@casper.infradead.org>
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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 8 Feb 2021 15:25:59 +0200
Message-ID: <CAHp75VfQzsx0dtmK9is8Y2WezV2gk7pqDqXZPfEVay722pWFfw@mail.gmail.com>
Subject: Re: [PATCH v3 0/3] mm, vsprintf: introduce new format to dump full
 information of page flags
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Yafang Shao <laoar.shao@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        david@redhat.com, vbabka@suse.cz, Christoph Lameter <cl@linux.com>,
        linmiaohe@huawei.com, Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Joe Perches <joe@perches.com>, linux-mm <linux-mm@kvack.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Feb 8, 2021 at 2:37 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Mon, Feb 08, 2021 at 06:14:36PM +0800, Yafang Shao wrote:
> > To avoid breaking some tools which parsing pGp via debugfs or affecting
> > the printf buffer, other new formats are introduced, so the user can choose
> > what and in which order they want, suggested by Andy. These new introduced
> > format as follows,
> >     pGpb: print other information first and then the names of page flags
> >     pGpl: print the names of page flags first and then the other info
>
> This is overengineering things.  We already print in little-endian order,
> and the other information should be tacked onto the end.  Just extend
> %pGp.  Andy's suggestion to add another flag was a bad one.

Fair enough, I can admit this because I don't know the mm specifics.
However, my initial point was about the long message which might be
cut into pieces during Oops or whatever and the user will get the
first parts only.  Depends on what you consider as a higher priority
to print the order might be different. Initial patch suggested to
print the new fields first.

-- 
With Best Regards,
Andy Shevchenko