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Message-ID: <c038e06504733e8dc6830f082c8522c60895fd8e.camel@perches.com>
Subject: Re: [RFC v2 3/3] mm, printk: introduce new format %pGt for page_type
From:   Joe Perches <joe@perches.com>
To:     Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Matthew Wilcox <willy@infradead.org>,
        Minchan Kim <minchan@kernel.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Hugh Dickins <hughd@google.com>,
        Muchun Song <songmuchun@bytedance.com>,
        David Hildenbrand <david@redhat.com>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Sun, 06 Nov 2022 10:04:25 -0800
In-Reply-To: <20221106140355.294845-4-42.hyeyoo@gmail.com>
References: <20221106140355.294845-1-42.hyeyoo@gmail.com>
         <20221106140355.294845-4-42.hyeyoo@gmail.com>
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On Sun, 2022-11-06 at 23:03 +0900, Hyeonggon Yoo wrote:
> dump_page() uses %pGp format to print 'flags' field of struct page.
> As some page flags (e.g. PG_buddy, see page-flags.h for more details)
> are set in page_type field, introduce %pGt format which provides
> human readable output of page_type. And use it in dump_page().
[]
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
[]
> @@ -2056,6 +2056,28 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
>  	return buf;
>  }
>  
> +static

noinline_for_stack ?

> +char *format_page_type(char *buf, char *end, unsigned int page_type)
> +{
> +	if (!(page_type & PAGE_TYPE_BASE))
> +		return string(buf, end, "no type for user-mapped page", default_str_spec);

Might be better with something like '%pGt: no type..."