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 X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BDA4CA9EA0 for ; Mon, 4 Nov 2019 10:12:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 347C420578 for ; Mon, 4 Nov 2019 10:12:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728344AbfKDKMy (ORCPT ); Mon, 4 Nov 2019 05:12:54 -0500 Received: from mga06.intel.com ([134.134.136.31]:49568 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727320AbfKDKMy (ORCPT ); Mon, 4 Nov 2019 05:12:54 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Nov 2019 02:12:52 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,266,1569308400"; d="scan'208";a="401562020" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.159.29]) by fmsmga005.fm.intel.com with ESMTP; 04 Nov 2019 02:12:51 -0800 From: "Huang\, Ying" To: Peter Zijlstra Cc: , , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Ingo Molnar , Dave Hansen , Dan Williams , Fengguang Wu Subject: Re: [RFC 10/10] autonuma, memory tiering: Adjust hot threshold automatically References: <20191101075727.26683-1-ying.huang@intel.com> <20191101075727.26683-11-ying.huang@intel.com> <20191101093145.GT4131@hirez.programming.kicks-ass.net> <877e4gcgsg.fsf@yhuang-dev.intel.com> <20191104084924.GB4131@hirez.programming.kicks-ass.net> Date: Mon, 04 Nov 2019 18:12:50 +0800 In-Reply-To: <20191104084924.GB4131@hirez.programming.kicks-ass.net> (Peter Zijlstra's message of "Mon, 4 Nov 2019 09:49:24 +0100") Message-ID: <87ftj4ar19.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Mon, Nov 04, 2019 at 02:11:11PM +0800, Huang, Ying wrote: >> Peter Zijlstra writes: >> >> > On Fri, Nov 01, 2019 at 03:57:27PM +0800, Huang, Ying wrote: >> > >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> >> index 0a83e9cf6685..22bdbb7afac2 100644 >> >> --- a/kernel/sched/fair.c >> >> +++ b/kernel/sched/fair.c >> >> @@ -1486,6 +1486,41 @@ static bool numa_migration_check_rate_limit(struct pglist_data *pgdat, >> >> return true; >> >> } >> >> >> >> +#define NUMA_MIGRATION_ADJUST_STEPS 16 >> >> + >> >> +static void numa_migration_adjust_threshold(struct pglist_data *pgdat, >> >> + unsigned long rate_limit, >> >> + unsigned long ref_threshold) >> >> +{ >> >> + unsigned long now = jiffies, last_threshold_jiffies; >> >> + unsigned long unit_threshold, threshold; >> >> + unsigned long try_migrate, ref_try_migrate, mdiff; >> >> + >> >> + last_threshold_jiffies = pgdat->autonuma_threshold_jiffies; >> >> + if (now > last_threshold_jiffies + >> >> + msecs_to_jiffies(sysctl_numa_balancing_scan_period_max) && >> >> + cmpxchg(&pgdat->autonuma_threshold_jiffies, >> >> + last_threshold_jiffies, now) == last_threshold_jiffies) { >> > >> > That is seriously unreadable gunk. >> >> The basic idea here is to adjust hot threshold every > > Oh, I figured out what it does, but it's just really hard to read > because of those silly variable names. > > This was just a first quick read through of the patches, and stuff like > this annoys me no end. I did start a rewrite with more sensible variable > names, but figured this might not be time for that. Sorry about the poor naming. That is always hard for me. > I still need to think and review the whole concept in more detail, now > that I've read the patches. But I need to chase regressions first :/ Thanks for your help! > FWIW, can you post a SLIT / NUMA distance table for such a system? Sure. Will send you as attachment in another email. Best Regards, Huang, Ying