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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 51736C433F5 for ; Tue, 28 Aug 2018 17:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF3AE2088E for ; Tue, 28 Aug 2018 17:23:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="jIhStVWD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF3AE2088E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cmpxchg.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727627AbeH1VQK (ORCPT ); Tue, 28 Aug 2018 17:16:10 -0400 Received: from mail-yb0-f195.google.com ([209.85.213.195]:40554 "EHLO mail-yb0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727468AbeH1VQJ (ORCPT ); Tue, 28 Aug 2018 17:16:09 -0400 Received: by mail-yb0-f195.google.com with SMTP id f4-v6so898274ybp.7 for ; Tue, 28 Aug 2018 10:23:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=7HJ/faUwNp70pvtX2vst2/bX0oNS92n5Rlox7XiLwSM=; b=jIhStVWDliq16204BH4yFa9JfJgW30tWLG33tq/hGkX5TwlOjEM92VNzEy1W/9O7pE cBjmnCwdKz8UyEdgbMFr76tZo60U94akOVfnGXPJwGhyJ2jAI6V5EDTlW3ue7cP8Yftu SO2cJUVsKNHMkuXOGhhs3rRs17g6cMePZcqzo3fCIh0X2kk147agMiJdTUrE/1sdntV7 tnRo+E4nB7P/z/MofV9CTqpmRHNbu2EVBa3T/hj8k/wUbpTq3DsTxnyZN+8+xiuxL+gf 97uIhkbqeig4moFP26DoLBm/yoFJkz7IdLsGW1BQoCbZHX5dSVYcG0/muFaHzH2Wi18f 3xhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=7HJ/faUwNp70pvtX2vst2/bX0oNS92n5Rlox7XiLwSM=; b=G/YfieVPohaKGsZFrBRxv7VD9uOFl45PBSNgZEgMmWwM8eRQfgIcrkyqyE+ewp2ct4 BWNi6H+JTbdlVUDuxDRY2n7o4/IewboC2+P3xSE5hiIoG6//+Ek+5ELIP9NxatVUHQxo wvy73kqXRzIsneyt/k2DjlDDsqkrZdxjRdwyzEznqjceb5AzN7y2gyG11VDtXm02Jguf Adzv3IXdAxzUSGL3fvTZq3EHgVWj0NqpaNRLysdR+2fvd8zPe56Dmm6d2ZDIgeIQBl7b TbgsqJGoHsfptetR7WRhg+LOlrqhyfp0PSNeqhTsaNSI0cKTfVY/F7CmrRPhXjhYEkJX A9Lg== X-Gm-Message-State: APzg51A2xyrjZM2r/mhos4gOpy8XlOuHkKiFW+flx8kBeQuI3UaZWU2g J/KlNX1608igRsaRKRma8YQ9qg== X-Google-Smtp-Source: ANB0VdaNGaFHS4gzWZuIso6V3BU/IJ/P6lbdlxSdFGuKMhZo33JAZOMAwn4+D5lt5EtqKGH3jOvo9Q== X-Received: by 2002:a25:6f84:: with SMTP id k126-v6mr1349981ybc.419.1535477009345; Tue, 28 Aug 2018 10:23:29 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::1:de86]) by smtp.gmail.com with ESMTPSA id p126-v6sm609517ywf.22.2018.08.28.10.23.27 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 28 Aug 2018 10:23:28 -0700 (PDT) From: Johannes Weiner To: Ingo Molnar , Peter Zijlstra , Andrew Morton , Linus Torvalds Cc: Tejun Heo , Suren Baghdasaryan , Daniel Drake , Vinayak Menon , Christopher Lameter , Peter Enderborg , Shakeel Butt , Mike Galbraith , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH 5/9] sched: loadavg: make calc_load_n() public Date: Tue, 28 Aug 2018 13:22:54 -0400 Message-Id: <20180828172258.3185-6-hannes@cmpxchg.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180828172258.3185-1-hannes@cmpxchg.org> References: <20180828172258.3185-1-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's going to be used in a later patch. Keep the churn separate. Signed-off-by: Johannes Weiner --- include/linux/sched/loadavg.h | 3 + kernel/sched/loadavg.c | 138 +++++++++++++++++----------------- 2 files changed, 72 insertions(+), 69 deletions(-) diff --git a/include/linux/sched/loadavg.h b/include/linux/sched/loadavg.h index cc9cc62bb1f8..4859bea47a7b 100644 --- a/include/linux/sched/loadavg.h +++ b/include/linux/sched/loadavg.h @@ -37,6 +37,9 @@ calc_load(unsigned long load, unsigned long exp, unsigned long active) return newload / FIXED_1; } +extern unsigned long calc_load_n(unsigned long load, unsigned long exp, + unsigned long active, unsigned int n); + #define LOAD_INT(x) ((x) >> FSHIFT) #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100) diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c index 54fbdfb2d86c..28a516575c18 100644 --- a/kernel/sched/loadavg.c +++ b/kernel/sched/loadavg.c @@ -91,6 +91,75 @@ long calc_load_fold_active(struct rq *this_rq, long adjust) return delta; } +/** + * fixed_power_int - compute: x^n, in O(log n) time + * + * @x: base of the power + * @frac_bits: fractional bits of @x + * @n: power to raise @x to. + * + * By exploiting the relation between the definition of the natural power + * function: x^n := x*x*...*x (x multiplied by itself for n times), and + * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, + * (where: n_i \elem {0, 1}, the binary vector representing n), + * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is + * of course trivially computable in O(log_2 n), the length of our binary + * vector. + */ +static unsigned long +fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) +{ + unsigned long result = 1UL << frac_bits; + + if (n) { + for (;;) { + if (n & 1) { + result *= x; + result += 1UL << (frac_bits - 1); + result >>= frac_bits; + } + n >>= 1; + if (!n) + break; + x *= x; + x += 1UL << (frac_bits - 1); + x >>= frac_bits; + } + } + + return result; +} + +/* + * a1 = a0 * e + a * (1 - e) + * + * a2 = a1 * e + a * (1 - e) + * = (a0 * e + a * (1 - e)) * e + a * (1 - e) + * = a0 * e^2 + a * (1 - e) * (1 + e) + * + * a3 = a2 * e + a * (1 - e) + * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) + * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) + * + * ... + * + * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] + * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) + * = a0 * e^n + a * (1 - e^n) + * + * [1] application of the geometric series: + * + * n 1 - x^(n+1) + * S_n := \Sum x^i = ------------- + * i=0 1 - x + */ +unsigned long +calc_load_n(unsigned long load, unsigned long exp, + unsigned long active, unsigned int n) +{ + return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); +} + #ifdef CONFIG_NO_HZ_COMMON /* * Handle NO_HZ for the global load-average. @@ -210,75 +279,6 @@ static long calc_load_nohz_fold(void) return delta; } -/** - * fixed_power_int - compute: x^n, in O(log n) time - * - * @x: base of the power - * @frac_bits: fractional bits of @x - * @n: power to raise @x to. - * - * By exploiting the relation between the definition of the natural power - * function: x^n := x*x*...*x (x multiplied by itself for n times), and - * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, - * (where: n_i \elem {0, 1}, the binary vector representing n), - * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is - * of course trivially computable in O(log_2 n), the length of our binary - * vector. - */ -static unsigned long -fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) -{ - unsigned long result = 1UL << frac_bits; - - if (n) { - for (;;) { - if (n & 1) { - result *= x; - result += 1UL << (frac_bits - 1); - result >>= frac_bits; - } - n >>= 1; - if (!n) - break; - x *= x; - x += 1UL << (frac_bits - 1); - x >>= frac_bits; - } - } - - return result; -} - -/* - * a1 = a0 * e + a * (1 - e) - * - * a2 = a1 * e + a * (1 - e) - * = (a0 * e + a * (1 - e)) * e + a * (1 - e) - * = a0 * e^2 + a * (1 - e) * (1 + e) - * - * a3 = a2 * e + a * (1 - e) - * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) - * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) - * - * ... - * - * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] - * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) - * = a0 * e^n + a * (1 - e^n) - * - * [1] application of the geometric series: - * - * n 1 - x^(n+1) - * S_n := \Sum x^i = ------------- - * i=0 1 - x - */ -static unsigned long -calc_load_n(unsigned long load, unsigned long exp, - unsigned long active, unsigned int n) -{ - return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); -} - /* * NO_HZ can leave us missing all per-CPU ticks calling * calc_load_fold_active(), but since a NO_HZ CPU folds its delta into -- 2.18.0