Date:   Fri, 3 Mar 2023 20:50:52 +0100
From:   Petr Mladek <pmladek@suse.com>
To:     Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Joe Perches <joe@perches.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew WilCox <willy@infradead.org>,
        David Hildenbrand <david@redhat.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH mm-unstable v4 2/3] mm, printk: introduce new format %pGt
 for page_type
Message-ID: <ZAJPnG2LqjvXkC/Z@alley>
References: <20230130042514.2418-1-42.hyeyoo@gmail.com>
 <20230130042514.2418-3-42.hyeyoo@gmail.com>
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On Mon 2023-01-30 13:25:13, Hyeonggon Yoo wrote:
> %pGp format is used to display 'flags' field of a struct page.
> However, some page flags (i.e. PG_buddy, see page-flags.h for more details)
> are stored in page_type field. To display human-readable output of
> page_type, introduce %pGt format.
> 
> It is important to note the meaning of bits are different in page_type.
> if page_type is 0xffffffff, no flags are set. Setting PG_buddy (0x00000080)
> flag results in a page_type of 0xffffff7f. Clearing a bit actually means
> setting a flag. Bits in page_type are inverted when displaying type names.
> 
> Only values for which page_type_has_type() returns true are considered
> as page_type, to avoid confusion with mapcount values. if it returns false,
> only raw values are displayed and not page type names.
> 
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Reviewed-by: Petr Mladek <pmladek@suse.com>   # for vsprintf part

I am sorry for the late review. It has somehow fallen through cracks.

Best Regards,
Petr