Re: [PATCH] mm: fix printk format within cma

[Andrew Morton]

On Tue, 18 Apr 2023 04:38:24 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> 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?