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Subject: Re: [PATCH] mm/slab: Increase width of first /proc/slabinfo column
To:     Christopher Lameter <cl@linux.com>,
        "Tobin C. Harding" <tobin@kernel.org>
Cc:     Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <20190201004242.7659-1-tobin@kernel.org>
 <01000168a6e8944d-b8e72739-2611-4649-a8d2-304b98529b7d-000000@email.amazonses.com>
From:   Pekka Enberg <penberg@iki.fi>
Message-ID: <ca008d08-0041-5277-e562-5212783ea6be@iki.fi>
Date:   Sat, 2 Feb 2019 08:47:03 +0200
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Hi,

On 01/02/2019 4.34, Christopher Lameter wrote:
> On Fri, 1 Feb 2019, Tobin C. Harding wrote:
> 
>> Currently when displaying /proc/slabinfo if any cache names are too long
>> then the output columns are not aligned.  We could do something fancy to
>> get the maximum length of any cache name in the system or we could just
>> increase the hardcoded width.  Currently it is 17 characters.  Monitors
>> are wide these days so lets just increase it to 30 characters.
> 
> Hmm.. I wonder if there are any tools that depend on the field width here?
> 

It's possible, but it's more likely that userspace parses by whitespace 
because it's easier to write it that way.

At least procps, which is used by slabtop, is prepared to parse a cache 
name of 128 characters. See the scanf() call in parse_slabinfo20() 
function in proc/slab.c of procps:

   http://procps.sourceforge.net/

Of course, testing with slabtop would make sense.

- Pekka