From: Michal Hocko <mhocko@suse.com>
To: David Hildenbrand <david@redhat.com>
Cc: Topi Miettinen <toiwoton@gmail.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: optionally disable brk()
Date: Mon, 5 Oct 2020 11:20:31 +0200 [thread overview]
Message-ID: <20201005092031.GS4555@dhcp22.suse.cz> (raw)
In-Reply-To: <888e62e0-3979-207b-c516-ddfc6b9f3345@redhat.com>
On Mon 05-10-20 11:13:48, David Hildenbrand wrote:
> On 05.10.20 08:12, Michal Hocko wrote:
> > On Sat 03-10-20 00:44:09, Topi Miettinen wrote:
> >> On 2.10.2020 20.52, David Hildenbrand wrote:
> >>> On 02.10.20 19:19, Topi Miettinen wrote:
> >>>> The brk() system call allows to change data segment size (heap). This
> >>>> is mainly used by glibc for memory allocation, but it can use mmap()
> >>>> and that results in more randomized memory mappings since the heap is
> >>>> always located at fixed offset to program while mmap()ed memory is
> >>>> randomized.
> >>>
> >>> Want to take more Unix out of Linux?
> >>>
> >>> Honestly, why care about disabling? User space can happily use mmap() if
> >>> it prefers.
> >>
> >> brk() interface doesn't seem to be used much and glibc is happy to switch to
> >> mmap() if brk() fails, so why not allow disabling it optionally? If you
> >> don't care to disable, don't do it and this is even the default.
> >
> > I do not think we want to have config per syscall, do we?
>
> I do wonder if grouping would be a better option then (finding a proper
> level of abstraction ...).
I have a vague recollection that project for the kernel tinification was
aiming that direction. No idea what is the current state or whether
somebody is pursuing it.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-10-05 9:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 17:19 [PATCH] mm: optionally disable brk() Topi Miettinen
2020-10-02 17:52 ` David Hildenbrand
2020-10-02 21:19 ` David Laight
2020-10-02 21:44 ` Topi Miettinen
2020-10-05 6:12 ` Michal Hocko
2020-10-05 8:11 ` Topi Miettinen
2020-10-05 8:22 ` Michal Hocko
2020-10-05 9:03 ` Topi Miettinen
2020-10-05 14:12 ` Jonathan Corbet
2020-10-05 16:14 ` Topi Miettinen
2020-10-05 9:13 ` David Hildenbrand
2020-10-05 9:20 ` Michal Hocko [this message]
2020-10-05 9:47 ` Topi Miettinen
2020-10-05 9:55 ` David Hildenbrand
2020-10-05 11:21 ` David Laight
2020-10-05 12:18 ` David Hildenbrand
2020-10-05 12:25 ` David Laight
2020-10-07 9:43 ` Topi Miettinen
2020-11-01 11:41 ` Topi Miettinen
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