Subject: Re: Some debugging patches on top of -mm
From: Alexander Nyberg <alexn@telia.com>
To: Paul Jackson <pj@sgi.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
In-Reply-To: <20051112031320.40543ae4.pj@sgi.com>
References: <20050905195001.GA10223@localhost.localdomain>
	 <20051112031320.40543ae4.pj@sgi.com>
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Date: Sat, 12 Nov 2005 21:26:07 +0100
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> This patch, known as page-owner-tracking-leak-detector.patch has
> apparently been sitting in Andrew's *-mm for the last two months.
> 
> I just noticed it now, when reading mm/page_alloc.c.
> 
> I'd like to know if the #ifdef's and CONFIG_PAGE_OWNER specific code
> can be removed from page_alloc.c, and put in a header file.  Ideally,
> you patch would add just one line to the __alloc_pages() code - a call
> to set_page_owner() that either became no code (a static inline empty
> function) or a call to your code, if this feature was CONFIG enabled.
> 
> The *.c files are where all the logic comes together, and it is vital
> to the long term readability of these files that we avoid #ifdef's in
> these files.  Any one feature can be ifdef'd in, with seeming little
> harm to the readability of the code (especially in the eyes of the
> author of that particular bit of ifdef'd code ;).  But imagine what
> a deity-awful mess these files would be if we had all been doing that
> over the years with our various favorite features.
> 

Yes, it was a quick hack when akpm said that he'd like a page tracking
mechanism. I said myself that I thought it was too ugly to go into
mainline. Later I tried to make it some kind of generic framework that
all arches could use but there was no interest.

If you wish to make it nicer/mergeable it's all yours.

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