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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43C2DC4332F for ; Wed, 16 Nov 2022 21:29:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6947D6B0073; Wed, 16 Nov 2022 16:29:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 644046B0074; Wed, 16 Nov 2022 16:29:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 50CED8E0001; Wed, 16 Nov 2022 16:29:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 40C766B0073 for ; Wed, 16 Nov 2022 16:29:03 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 003EC1A061B for ; Wed, 16 Nov 2022 21:29:02 +0000 (UTC) X-FDA: 80140595724.01.8EDD594 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf10.hostedemail.com (Postfix) with ESMTP id A75A3C0005 for ; Wed, 16 Nov 2022 21:29:02 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DC1CB61F8E; Wed, 16 Nov 2022 21:29:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0958FC433C1; Wed, 16 Nov 2022 21:29:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1668634141; bh=0kwXMMaWQoowwZaUSia1gptXZ3IFRHypINgR5ZFzPUo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fubJun5fP98ugUz3EQElgHkgSFdtOPgxOdL0aWbVm8WwyBqINUURDI5KEbtlvEcX9 u54dNdG3TZrU6pAkOONjM1o6o1ber7yt+oyeGCOxFzZ8ibowdaachemgBaT5Bs1pQ9 aof1uYvF7qSNtS6yUVj8TfHGkqLcdf2ghLv9o41U= Date: Wed, 16 Nov 2022 13:29:00 -0800 From: Andrew Morton To: Stefan Roesch Cc: kernel-team@fb.com, linux-block@vger.kernel.org, linux-mm@kvack.org, axboe@kernel.dk, clm@meta.com, willy@infradead.org, hch@infradead.org Subject: Re: [RFC PATCH v3 04/14] mm: use part per 1000 for bdi ratios. Message-Id: <20221116132900.ab7554e7e8342c4d30739bb1@linux-foundation.org> In-Reply-To: <20221024190603.3987969-5-shr@devkernel.io> References: <20221024190603.3987969-1-shr@devkernel.io> <20221024190603.3987969-5-shr@devkernel.io> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668634142; a=rsa-sha256; cv=none; b=3fl9/RXur9ZU6zWmE8clmldXIXM0dP57EDcCvYhcUSVNW0YeUWuji1/TKNWYWCZ2jKiyY+ Zdj7Vnok+9FYJ1uccyeuwMsLUf8K7KgMlgtQQQErfogupZ24/qLf7TUDoEmnzG3f6CkAo+ cTzJR/8V4+FFRzOvBpcRlz0obGQKW2w= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=fubJun5f; dmarc=none; spf=pass (imf10.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668634142; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1d/ieSN1LGvxRLeccPi799PXCaeeOFo2VmyWoyUG/Ts=; b=LPXjLTBZs9hHcmj527Jm0YrIYV3/DhOurMEswma/sBG4aLhJ0InkkRamKOF5EKG7glmY5w APXf4/F8UKYuYwssw3ayQbaqdkocPCdTu8KusOuz5DL7J2nrhoZKeUCjzE6rp9mci4e6wg pqcW3F9zRPkMg55YWj9iDuYlbdc6JpU= X-Stat-Signature: 8p3bgb9nxf564dwgpfgn1941sprgo6er X-Rspamd-Queue-Id: A75A3C0005 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=fubJun5f; dmarc=none; spf=pass (imf10.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam09 X-HE-Tag: 1668634142-720921 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 Mon, 24 Oct 2022 12:05:53 -0700 Stefan Roesch wrote: > To get finer granularity for ratio calculations use part per 1000 > instead of percentiles. This is especially important if we want to > automatically convert byte values to ratios. Otherwise the values that > are actually used can be quite different. This is also important for > machines with more main memory (1% of 256GB is already 2.5GB). > > ... > This changes an existing userspace interface, doesn't it? /sys/class/bdi//min_ratio. Can't do that! We could add a new interace to the same thing, I guess. /sys/class/bdi//min_ratio_fine or whatever. We might want to go for more than 100->1000, too. Otherwise in a few years we'll be adding /sys/class/bdi//min_ratio_even_finer. Also, this patch forgot to update Documentation/ABI/testing/sysfs-class-bdi.