From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 9ED8C6B0260 for ; Mon, 27 Nov 2017 11:22:09 -0500 (EST) Received: by mail-pf0-f198.google.com with SMTP id s9so10985723pfe.20 for ; Mon, 27 Nov 2017 08:22:09 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id q17si22798353pgt.617.2017.11.27.08.22.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Nov 2017 08:22:08 -0800 (PST) Date: Mon, 27 Nov 2017 08:22:07 -0800 From: Matthew Wilcox Subject: Re: [PATCH] mm: disable `vm.max_map_count' sysctl limit Message-ID: <20171127162207.GA8265@bombadil.infradead.org> References: <23066.59196.909026.689706@gargle.gargle.HOWL> <20171127101232.ykriowhatecnvjvg@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171127101232.ykriowhatecnvjvg@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Mikael Pettersson , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org