Re: [PATCH] Do not print page type when the page has no type

[Hyeonggon Yoo <42.hyeyoo@gmail.com>]

On Sat, May 27, 2023 at 05:48:32PM +0100, Matthew Wilcox wrote:
> It is confusing and unnecessary to print the page type when the
> page has no type.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> 
> ---
> 
> I did not run the test-suite.  I'm in the middle of debugging something
> else and this is an unwelcome distraction.  If this doesn't work quite
> right, please fix it.

I ran the test suite, and a test case failed:

[    1.001641] test_printf: loaded.
[    1.001736] test_printf: vsnprintf(buf, 256, "%pGt", ...) returned 41, expected 5
[    1.001738] test_printf: vsnprintf(buf, 2, "%pGt", ...) returned 41, expected 5
[    1.001738] test_printf: vsnprintf(buf, 0, "%pGt", ...) returned 41, expected 5
[    1.001739] test_printf: kvasprintf(..., "%pGt", ...) returned '0xa(offline|guard|table|buddy|0xfffff875)', expected '0xa()'
[    1.001774] test_printf: failed 4 out of 432 tests

The code mostly looks fine and the patch makes sense to me.
But I'm not sure if it's a nice behavior to print garbage when it does not
have a page type, although I can hardly imagine users of this flag other
than __dump_page(). I'd rather keep printk part unchanged and add
page_has_type() check in __dump_page().

Thanks!

-- 
Hyeonggon Yoo

Doing kernel stuff as a hobby
Undergraduate | Chungnam National University
Dept. Computer Science & Engineering