From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71])
	by kanga.kvack.org (Postfix) with ESMTP id C08356B0003
	for <linux-mm@kvack.org>; Fri, 29 Jun 2018 22:41:21 -0400 (EDT)
Received: by mail-pl0-f71.google.com with SMTP id m2-v6so6030252plt.14
        for <linux-mm@kvack.org>; Fri, 29 Jun 2018 19:41:21 -0700 (PDT)
Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12])
        by mx.google.com with ESMTPS id f4-v6si9289081pgc.522.2018.06.29.19.41.20
        for <linux-mm@kvack.org>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Fri, 29 Jun 2018 19:41:20 -0700 (PDT)
Date: Fri, 29 Jun 2018 19:41:17 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v4 00/17] khwasan: kernel hardware assisted address
 sanitizer
Message-Id: <20180629194117.01b2d31e805808eee5c97b4d@linux-foundation.org>
In-Reply-To: <CAAeHK+xsBOKghUp9XhpfXGqU=gjSYuy3G2GH14zWNEmaLPy8_w@mail.gmail.com>
References: <cover.1530018818.git.andreyknvl@google.com>
	<20180627160800.3dc7f9ee41c0badbf7342520@linux-foundation.org>
	<CAAeHK+xz552VNpZxgWwU-hbTqF5_F6YVDw3fSv=4OT8mNrqPzg@mail.gmail.com>
	<20180628124039.8a42ab5e2994fb2876ff4f75@linux-foundation.org>
	<CAAeHK+xsBOKghUp9XhpfXGqU=gjSYuy3G2GH14zWNEmaLPy8_w@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Christoph Lameter <cl@linux.com>, Mark Rutland <mark.rutland@arm.com>, Nick Desaulniers <ndesaulniers@google.com>, Marc Zyngier <marc.zyngier@arm.com>, Dave Martin <dave.martin@arm.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, "Eric W . Biederman" <ebiederm@xmission.com>, Ingo Molnar <mingo@kernel.org>, Paul Lawrence <paullawrence@google.com>, Geert Uytterhoeven <geert@linux-m68k.org>, Arnd Bergmann <arnd@arndb.de>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Kate Stewart <kstewart@linuxfoundation.org>, Mike Rapoport <rppt@linux.vnet.ibm.com>, kasan-dev <kasan-dev@googlegroups.com>, linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, linux-sparse@vger.kernel.org, Linux Memory Management List <linux-mm@kvack.org>, Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>, Kostya Serebryany <kcc@google.com>, Evgeniy Stepanov <eugenis@google.com>, Lee Smith <Lee.Smith@arm.com>, Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>, Jacob Bramley <Jacob.Bramley@arm.com>, Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>, Jann Horn <jannh@google.com>, Mark Brand <markbrand@google.com>, Chintan Pandya <cpandya@codeaurora.org>

On Fri, 29 Jun 2018 14:45:08 +0200 Andrey Konovalov <andreyknvl@google.com> wrote:

> >> What kind of memory consumption testing would you like to see?
> >
> > Well, 100kb or so is a teeny amount on virtually any machine.  I'm
> > assuming the savings are (much) more significant once the machine gets
> > loaded up and doing work?
> 
> So with clean kernel after boot we get 40 kb memory usage. With KASAN
> it is ~120 kb, which is 200% overhead. With KHWASAN it's 50 kb, which
> is 25% overhead. This should approximately scale to any amounts of
> used slab memory. For example with 100 mb memory usage we would get
> +200 mb for KASAN and +25 mb with KHWASAN. (And KASAN also requires
> quarantine for better use-after-free detection). I can explicitly
> mention the overhead in %s in the changelog.
> 
> If you think it makes sense, I can also make separate measurements
> with some workload. What kind of workload should I use?

Whatever workload people were running when they encountered problems
with KASAN memory consumption ;)

I dunno, something simple.  `find / > /dev/null'?