Re: [PATCH 11/19] perf record: Release resources at exit

From: Ingo Molnar
Date: Mon Aug 02 2010 - 03:54:42 EST



* Nick Piggin <npiggin@xxxxxxx> wrote:

> On Sun, Aug 01, 2010 at 10:08:46PM -0300, Arnaldo Carvalho de Melo wrote:
> > From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> >
> > So that we can reduce the noise on valgrind when looking for memory
> > leaks.
>
> Really? That's rather crappy of valgrind. exit is well defined to release
> resources and that's often a more efficient way to do it It finds and
> batches things a lot better, eg. it can avoid all TLB flushing of freeing
> memory that munmap requires.

That's certainly true but there's no valgrind crappiness here: valgrind simply
can do a better job of finding leaks if there's a well defined "all resources
the app still knows about are freed now" point.

The _kernel_ obviously can release all resources. The distinction is between
'resources known to the app' and 'all resources'. That set contains the
leaking resources.

Thanks,

Ingo
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