From: Matthew Wilcox <willy@infradead.org>
To: Michal Hocko <mhocko@kernel.org>
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 08:22:07 -0800 [thread overview]
Message-ID: <20171127162207.GA8265@bombadil.infradead.org> (raw)
In-Reply-To: <20171127101232.ykriowhatecnvjvg@dhcp22.suse.cz>
On Mon, Nov 27, 2017 at 11:12:32AM +0100, Michal Hocko wrote:
> On Sun 26-11-17 17:09:32, Mikael Pettersson wrote:
> > - Reaching the limit causes various memory management system calls to
> > fail with ENOMEM, which is a lie. Combined with the unpredictability
> > of the number of mappings in a process, especially when non-trivial
> > memory management or heavy file mapping is used, it can be difficult
> > to reproduce these events and debug them. It's also confusing to get
> > ENOMEM when you know you have lots of free RAM.
[snip]
> Could you be more explicit about _why_ we need to remove this tunable?
> I am not saying I disagree, the removal simplifies the code but I do not
> really see any justification here.
I imagine he started seeing random syscalls failing with ENOMEM and
eventually tracked it down to this stupid limit we used to need.
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next prev parent reply other threads:[~2017-11-27 16:22 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 [this message]
2017-11-27 19:28 ` Mikael Pettersson
2017-11-27 17:25 ` Andi Kleen
2017-11-27 18:32 ` Michal Hocko
2017-11-27 19:57 ` Michal Hocko
2017-11-27 20:21 ` Andi Kleen
2017-11-27 20:52 ` Michal Hocko
2017-11-27 19:36 ` Mikael Pettersson
2017-11-27 19:18 ` Mikael Pettersson
2017-11-27 19:52 ` Michal Hocko
2017-11-27 23:26 ` John Hubbard
2017-11-28 8:12 ` Michal Hocko
2017-11-29 5:14 ` John Hubbard
2017-11-29 8:32 ` Michal Hocko
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