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From: Andrew Morton <akpm@linux-foundation.org>
To: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: catalin.marinas@arm.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH 2/2] scripts: add kmemleak2pprof.py for slab usage analysis
Date: Thu, 30 Aug 2018 17:21:05 -0700	[thread overview]
Message-ID: <20180830172105.3f30f3831c370f51e2067a6c@linux-foundation.org> (raw)
In-Reply-To: <20180830072939.i33m43mj7uslhvmz@axis.com>

On Thu, 30 Aug 2018 09:29:40 +0200 Vincent Whitchurch <vincent.whitchurch@axis.com> wrote:

> On Tue, Aug 28, 2018 at 04:28:04PM -0700, Andrew Morton wrote:
> > On Tue, 28 Aug 2018 12:39:14 +0200 Vincent Whitchurch <vincent.whitchurch@axis.com> wrote:
> > 
> > > Add a script which converts /sys/kernel/debug/kmemleak_all to the pprof
> > > format, which can be used for analysing memory usage.  See
> > > https://github.com/google/pprof.
> > 
> > Why is this better than /proc/slabinfo?
> 
> slabinfo just tells you how much memory is being used in a particular
> slab, it doesn't give you a breakdown of who allocated all that memory.
> slabinfo can't also tell you how much memory a particular subsystem is
> using.
> 
> For example, here we can see that tracer_init_tracefs() and its callers
> are using ~12% of the total tracked memory:
> 
>  $ pprof -top -compact_labels -cum prof 
>  Showing nodes accounting for 13418.95kB, 92.07% of 14575.28kB total
>  Dropped 4069 nodes (cum <= 72.88kB)
>        flat  flat%   sum%        cum   cum%
>        ...
>           0     0% 56.71%  1832.15kB 12.57%  tracer_init_tracefs+0x74/0x1cc
> 
>  
> And that tracefs' dentrys use 500 KiB and its inodes use 1+ MiB:
>  	
>  $ pprof -text -compact_labels -focus tracer_init_tracefs -nodecount 2 prof
>  Main binary filename not available.
>  Showing nodes accounting for 1794.85kB, 12.31% of 14575.28kB total
>  Dropped 1912 nodes (cum <= 72.88kB)
>  Showing top 2 nodes out of 32
>        flat  flat%   sum%        cum   cum%
>   1294.56kB  8.88%  8.88%  1294.56kB  8.88%  new_inode_pseudo+0x8/0x4c
>    500.29kB  3.43% 12.31%   500.29kB  3.43%  d_alloc+0x10/0x78
>    ...

OK, thanks.  Please include this info in future changelogs?

      reply	other threads:[~2018-08-31  0:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-28 10:39 [PATCH 1/2] kmemleak: dump all objects " Vincent Whitchurch
2018-08-28 10:39 ` [PATCH 2/2] scripts: add kmemleak2pprof.py " Vincent Whitchurch
2018-08-28 23:28   ` Andrew Morton
2018-08-30  7:29     ` Vincent Whitchurch
2018-08-31  0:21       ` Andrew Morton [this message]

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