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Subject: Re: [RFCv3][PATCH 4/4] show page size in /proc/$pid/numa_maps
From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, James.Bottomley@hansenpartnership.com,
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Date: Wed, 05 Oct 2011 09:09:24 +0200
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Le mardi 04 octobre 2011 à 23:50 -0700, David Rientjes a écrit :

> This would be great if all the /proc/pid/numa_maps consumers were human, 
> but unfortuantely that's not the case.  
> 
> I understand that this patchset was probably the result of me asking for 
> the pagesize= to be specified in each line and using pagesize=4K and 
> pagesize=2M as examples, but that exact usage is probably not what we 
> want.
> 
> As long as there are scripts that go through and read this information 
> (we have some internally), expressing them with differing units just makes 
> it more difficult to parse.  I'd rather them just be the byte count.
> 
> That way, 1G pages would just show pagesize=1073741824.  I don't think 
> that's too long and is much easier to parse systematically.
> 

Hmm... Thats sounds strange.

Are you saying you cant change your scripts [But you'll have to anyway
to parse pagesize=] ?

I routinely use "cat /proc/xxx/numa_maps", and am stuck when a kernel
displays nothing (it happened on some debian released kernels)

Seeing pagesize=1GB is slightly better for human, and not that hard to
parse for a program.

By the way, "pagesize=4KiB" are just noise if you ask me, thats the
default PAGE_SIZE. This also breaks old scripts :)