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From: "Tobin C. Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>,
	"Tobin C. Harding" <tobin@kernel.org>,
	Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/slab: Increase width of first /proc/slabinfo column
Date: Mon, 4 Feb 2019 16:55:26 +1100	[thread overview]
Message-ID: <20190204055526.GA14242@eros.localdomain> (raw)
In-Reply-To: <20190201140346.fdcd6c4b663fbe3b5d93820d@linux-foundation.org>

On Fri, Feb 01, 2019 at 02:03:46PM -0800, Andrew Morton wrote:
> On Thu, 31 Jan 2019 18:43:10 -0800 Matthew Wilcox <willy@infradead.org> wrote:
> 
> > On Fri, Feb 01, 2019 at 11:42:42AM +1100, 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.
> > 
> > I had a proposal some time ago to turn the slab name from being kmalloced
> > to being an inline 16 bytes (with some fun hacks for cgroups).  I think
> > that's a better approach than permitting such long names.  For example,
> > ext4_allocation_context could be shortened to ext4_alloc_ctx without
> > losing any expressivity.
> > 
> 
> There are some back-compatibility concerns here.

I'm don't understand sorry what back-compatibility concerns (please see
sentiment at end of email :)

> And truncating long names might result in duplicates.

So I thought I had a good idea - add a pr_warn() if cache name > 16 and
patch all current intree calls to kmem_cache_create() called as such.

This process very kindly lead me to the fact that this does *not* work
because of the macro KMEM_CACHE (which uses the struct name as the cache
name).

So, back to the drawing board.  I'm concerned that this may be a waste
of peoples time, if so please say so and I'll move on to something else.

thanks,
Tobin.

  reply	other threads:[~2019-02-04  5:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01  0:42 [PATCH] mm/slab: Increase width of first /proc/slabinfo column Tobin C. Harding
2019-02-01  0:58 ` Tobin C. Harding
2019-02-01  1:13   ` Andrew Morton
2019-02-01  2:56     ` Tobin C. Harding
2019-02-01  2:34 ` Christopher Lameter
2019-02-02  6:47   ` Pekka Enberg
2019-02-01  2:43 ` Matthew Wilcox
2019-02-01  2:58   ` Tobin C. Harding
2019-02-01 22:03   ` Andrew Morton
2019-02-04  5:55     ` Tobin C. Harding [this message]
2019-02-04  1:35   ` Tobin C. Harding
2019-02-02  3:27 ` Joe Perches
2019-02-03 23:34   ` Tobin C. Harding

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