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 233E3C02182 for ; Wed, 22 Jan 2025 01:37:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AE398280002; Tue, 21 Jan 2025 20:37:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A9210280001; Tue, 21 Jan 2025 20:37:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 95B0D280002; Tue, 21 Jan 2025 20:37:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 77B49280001 for ; Tue, 21 Jan 2025 20:37:29 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 292751211C8 for ; Wed, 22 Jan 2025 01:37:29 +0000 (UTC) X-FDA: 83033375418.13.0990C1D Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) by imf22.hostedemail.com (Postfix) with ESMTP id 1BB58C0007 for ; Wed, 22 Jan 2025 01:37:25 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=FYIZw9jD; spf=pass (imf22.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.124 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1737509847; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rT1fOpwUiVwPsQgO7JwgisGYgbIhkRsKCAiqVZXk6/o=; b=E9JDHTmeEZwfOqxowx8ABNyZ3d9U7XcAzDd1q2z6DZB28S6DCvoItHZhuqA7tlY6qv3NLN dnh23n4MMSG+A6JQ3yyh9oUY6wRep4XXCXt4JlbzYAU/BGpRBvWYM/yvYtbU0AOKJYPl5N /11X0KuRsZDJN/cUz39B4CfsNLBYEiE= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1737509847; a=rsa-sha256; cv=none; b=anHOjOfDUuRYPN/dQZdfOTKA9PD101IQd1VQ1ComDX9aA1cAOpzQ1rrOFMvp+7ACV5gQa5 uKnTwit13xhuyZF7wzXwDA8Myd8GwuGt7YAs0GQ0o2Tfm4v5UX3gQyEQtcFW7pc8Ogjq56 dePD3cJs6o9mjS4ZM18xE9D+jjEU1Qc= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=FYIZw9jD; spf=pass (imf22.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.124 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1737509842; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=rT1fOpwUiVwPsQgO7JwgisGYgbIhkRsKCAiqVZXk6/o=; b=FYIZw9jDWJ8jjr5dS61xnCunpghnogYhLcDlL3rxb3YBp2d+A8FKzOul37R3cyJJTTqn4yiJHEaJeQjLe+6vDjYekQoDmuMHT5GbHhoFeHvwS9JlPs4ZDniC0crSLlHDMgGk1ksOWvcF4YRKJc+fZo68Qb6BpjADlJOHLBF3x5w= Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0WO6fJNc_1737509840 cluster:ay36) by smtp.aliyun-inc.com; Wed, 22 Jan 2025 09:37:21 +0800 From: "Huang, Ying" To: Gregory Price Cc: Joshua Hahn , hyeonggon.yoo@sk.com, rafael@kernel.org, lenb@kernel.org, gregkh@linuxfoundation.org, akpm@linux-foundation.org, honggyu.kim@sk.com, rakie.kim@sk.com, dan.j.williams@intel.com, Jonathan.Cameron@huawei.com, dave.jiang@intel.com, horen.chuang@linux.dev, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com Subject: Re: [PATCH v3] Weighted interleave auto-tuning In-Reply-To: (Gregory Price's message of "Tue, 21 Jan 2025 14:56:35 -0500") References: <20250115185854.1991771-1-joshua.hahnjy@gmail.com> <87ikq8h0w4.fsf@DESKTOP-5N7EMDA> Date: Wed, 22 Jan 2025 09:37:20 +0800 Message-ID: <8734hbiq7j.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Queue-Id: 1BB58C0007 X-Stat-Signature: qdd5uatj3ah19ds41zxnmt97zzqg1r3h X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1737509845-264874 X-HE-Meta: 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 qdKWmZdj 2yjQnn0liaxJOavgaGLkyW0PXH1f+dlFDcRWEqrv9AOI8hfcMyjoFuZT+pFywdIGTqHsluKldQeR51eSiRX0VwoCS3T+4iVxdzKf4JZo6NsgDPTkM31GqtS0vm3gDgGpSyCacW9Npd6EDzpAL5jkUx8UjvR5aJbHqkwwOm3Xn8P3/S2sVXFsJPmXIzd5JOhZmlLw7JGYjzjfF8P/maClPJopqEQPT+nILwQr5QrzqJRTddM0OQxvo+p6vmIWMDFYZ8izpaQwBuY7RL0L3fbu6ONwaQsETFEdlxZ10Y12K8D9nroVujOprIpyERV0p1LiDrhL7hjGGLqDveN+GFt5mxjmeyQ== 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: List-Subscribe: List-Unsubscribe: Gregory Price writes: > On Tue, Jan 21, 2025 at 07:17:15PM +0800, Huang, Ying wrote: > ... snip ... >> >> Unless it's possible we will add more modes in the future, this is kind >> of overkill for me. How about something simpler as below? >> >> $ cat auto >> true >> $ echo 0 > auto >> $ cat auto >> false > > We have discussed having a dynamic-mode where the weights might adjust > on the fly based on system-state, but i think this ends up being > controlled under mempolicy/dynamic_interleave or something. > > So this seems reasonable. > >> > static u8 __rcu *iw_table; >> > static DEFINE_MUTEX(iw_table_lock); >> > +static const int weightiness = 32; >> > +static bool weighted_interleave_auto = true; >> >> I still prefer to use 2 iw_table, one is for default, the other is for >> manual. The default one will be used if the manual one is NULL. Both >> are protected by RCU. The default one can be updated upon hotplug >> blindly. This makes the whole model easier to be understood IMHO. >> >> What do you think about that. >> > > only question is, lets say you have > > `cat auto node0 node1` -> `true 5 1` > and you do > echo 0 > auto > > what should a subsequent `cat auto node0 node1` output? > > `false 5 1` > or > `false 1 1` IMO, it should be `false 5 1` That is, we copy auto-generated weights to manual weights atomically and use it. > Then lets say we do > echo 7 > node0 Now, `cat auto node0 node1` outputs, `false 7 1` That is, we delete manual weights and use the auto-generated ones. > what should > echo true > auto > result in? > > `true 5 1` > or > `true 7 1` It should be `true 5 1` > The current code makes sure that when you switch modes from auto > to manual, it inherits the current state - instead of there being > some hidden state that suddenly takes precedence. I think that we can do that with two weight arrays. > So I prefer to just have one IW array and no hidden state. Then, when we switch from manual to auto mode, where to find auto-generated weights? Re-calculate them? --- Best Regards, Huang, Ying