Re: [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions

From: Joe Perches <joe@perches.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Minchan Kim <minchan@kernel.org>,
	Pekka Enberg <penberg@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Michal Hocko <mhocko@suse.cz>,
	David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	sergey.senozhatsky.work@gmail.com
Subject: Re: [RFC][PATCH 0/5] do not dereference NULL pools in pools' destroy() functions
Date: Tue, 09 Jun 2015 21:47:51 -0700	[thread overview]
Message-ID: <1433911671.2730.102.camel@perches.com> (raw)
In-Reply-To: <20150609191755.867a36c3.akpm@linux-foundation.org>

On Tue, 2015-06-09 at 19:17 -0700, Andrew Morton wrote:
> On Tue, 9 Jun 2015 21:00:58 -0500 (CDT) Christoph Lameter <cl@linux.com> wrote:
> > On Tue, 9 Jun 2015, Andrew Morton wrote:
> > > > Why do this at all?
> > Did some grepping and I did see some call sites that do this but the
> > majority has to do other processing as well.
> > 
> > 200 call sites? Do we have that many uses of caches? Typical prod system
> > have ~190 caches active and the merging brings that down to half of that.
> I didn't try terribly hard.
> z:/usr/src/linux-4.1-rc7> grep -r -C1 kmem_cache_destroy .  | grep "if [(]" | wc -l
> 158
> 
> It's a lot, anyway.

Yeah.

$ git grep -E -B1 -w "(kmem_cache|mempool|dma_pool)_destroy" *| \
  grep -P "\bif\s*\(" | wc -l
268