From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B56EC433F5 for ; Tue, 16 Nov 2021 21:38:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EDD4961502 for ; Tue, 16 Nov 2021 21:38:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EDD4961502 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 6AD396B006C; Tue, 16 Nov 2021 16:38:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 65D5F6B0071; Tue, 16 Nov 2021 16:38:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54B566B0072; Tue, 16 Nov 2021 16:38:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0185.hostedemail.com [216.40.44.185]) by kanga.kvack.org (Postfix) with ESMTP id 477D66B006C for ; Tue, 16 Nov 2021 16:38:04 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0A7161814C3D3 for ; Tue, 16 Nov 2021 21:37:54 +0000 (UTC) X-FDA: 78816106068.08.AC062B7 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf10.hostedemail.com (Postfix) with ESMTP id 248796001981 for ; Tue, 16 Nov 2021 21:37:37 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 5D63461263; Tue, 16 Nov 2021 21:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1637098672; bh=aut4rZmVSqmvPDGWnVKMPUXMUilpN5ktFpJnFx75cyU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=0cKcHMIi8KdXlMQJmAQdEEfbVfjIlTVsKC0Kx1JFgqNshbstFV1fP76hzsonyFdGs /dGMQBYUTB0DwhJnNblcxR70uOwpNPliVVx0/JfYSKRUI0tjhd6EvqzmZmX25+QaQU jq+DnMujwUeBzPZ1fp2YzvFGPyAGomB+JyiSvtfI= Date: Tue, 16 Nov 2021 13:37:50 -0800 From: Andrew Morton To: "Drew DeVault" Cc: "Ammar Faizi" , , , "io_uring Mailing List" , "Jens Axboe" , "Pavel Begunkov" , Subject: Re: [PATCH] Increase default MLOCK_LIMIT to 8 MiB Message-Id: <20211116133750.0f625f73a1e4843daf13b8f7@linux-foundation.org> In-Reply-To: References: <20211028080813.15966-1-sir@cmpwn.com> <593aea3b-e4a4-65ce-0eda-cb3885ff81cd@gnuweeb.org> <20211115203530.62ff33fdae14927b48ef6e5f@linux-foundation.org> <20211116114727.601021d0763be1f1efe2a6f9@linux-foundation.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: xuhncgqcbp755pj5g86c7g6jxxeaazue X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 248796001981 Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=0cKcHMIi; spf=pass (imf10.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-HE-Tag: 1637098657-345646 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 16 Nov 2021 20:48:48 +0100 "Drew DeVault" wrote: > On Tue Nov 16, 2021 at 8:47 PM CET, Andrew Morton wrote: > > Well, why change the default? Surely anyone who cares is altering it > > at runtime anyway. And if they are not, we should encourage them to do > > so? > > I addressed this question in the original patch's commit message. Kinda. We're never going to get this right, are we? The only person who can decide on a system's appropriate setting is the operator of that system. Haphazardly increasing the limit every few years mainly reduces incentive for people to get this right. And people who test their software on 5.17 kernels will later find that it doesn't work on 5.16 and earlier, so they still need to tell their users to configure their systems appropriately. Until 5.16 is obsolete, by which time we're looking at increasing the default again. I don't see how this change gets us closer to the desired state: getting distros and their users to configure their systems appropriately.