From: Michal Hocko <mhocko@kernel.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Mikael Pettersson <mikpelinux@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org
Subject: Re: [PATCH] mm: disable `vm.max_map_count' sysctl limit
Date: Mon, 27 Nov 2017 21:52:10 +0100 [thread overview]
Message-ID: <20171127205210.zmah36uliajnbjon@dhcp22.suse.cz> (raw)
In-Reply-To: <20171127202121.GB3070@tassilo.jf.intel.com>
On Mon 27-11-17 12:21:21, Andi Kleen wrote:
> On Mon, Nov 27, 2017 at 08:57:32PM +0100, Michal Hocko wrote:
> > On Mon 27-11-17 19:32:18, Michal Hocko wrote:
> > > On Mon 27-11-17 09:25:16, Andi Kleen wrote:
> > [...]
> > > > The reason the limit was there originally because it allows a DoS
> > > > attack against the kernel by filling all unswappable memory up with VMAs.
> > >
> > > We can reduce the effect by accounting vmas to memory cgroups.
> >
> > As it turned out we already do.
> > vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
>
> That only helps if you have memory cgroups enabled. It would be a regression
> to break the accounting on all the systems that don't.
I agree. And I didn't say we should remove the existing limit. I am just
saying that we can reduce existing problems by increasing the limit and
relying on memcg accounting where possible.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-11-27 20:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-26 16:09 [PATCH] mm: disable `vm.max_map_count' sysctl limit Mikael Pettersson
2017-11-27 10:12 ` Michal Hocko
2017-11-27 16:22 ` Matthew Wilcox
[not found] ` <20171127162207.GA8265-PfSpb0PWhxZc2C7mugBRk2EX/6BAtgUQ@public.gmane.org>
2017-11-27 19:28 ` Mikael Pettersson
2017-11-27 17:25 ` Andi Kleen
[not found] ` <87vahv8whv.fsf-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-11-27 18:32 ` Michal Hocko
2017-11-27 19:57 ` Michal Hocko
[not found] ` <20171127195732.3hkfx57d3ytyccvp-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-11-27 20:21 ` Andi Kleen
2017-11-27 20:52 ` Michal Hocko [this message]
2017-11-27 19:36 ` Mikael Pettersson
[not found] ` <20171127101232.ykriowhatecnvjvg-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-11-27 19:18 ` Mikael Pettersson
[not found] ` <CAM43=SPVvBTPz31Uu=iz3fpS9tb75uSmL=pYP3AfsfmYr9u4Og-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-11-27 19:52 ` Michal Hocko
[not found] ` <20171127195207.vderbbkbgygawuhx-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-11-27 23:26 ` John Hubbard
2017-11-28 8:12 ` Michal Hocko
2017-11-29 5:14 ` John Hubbard
[not found] ` <5ca7d54b-5ae4-646d-f3a0-9b85129c9ccf-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2017-11-29 8:32 ` Michal Hocko
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