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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D68B8C54E8D for ; Mon, 11 May 2020 12:36:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B551520746 for ; Mon, 11 May 2020 12:36:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="IXydZQPY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730079AbgEKMgz (ORCPT ); Mon, 11 May 2020 08:36:55 -0400 Received: from smtp-fw-9101.amazon.com ([207.171.184.25]:65330 "EHLO smtp-fw-9101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729309AbgEKMgy (ORCPT ); Mon, 11 May 2020 08:36:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1589200614; x=1620736614; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=gm3RkgBnFlsR0KLH3wADEsc5/8hUuBZNui1ctNCxs+I=; b=IXydZQPY2T8TD0lqihRT0yIYqDx+FFgQMYBThgp1CExFlc0yP4gZ4Gqw GUIslID03Sxxwpi2B7G8UhRvTCMEqbkCTJdkgUVP+tp6lbc73bivlG4SZ 8gJ7L9GE1KNbtnWetE8ODn1MDOKJWGaUsaAlJoviQUV3pMfTtQB1Atr7x Y=; IronPort-SDR: bD3UbNFmyebn4uwq18PQt0i8oiWF+RXahclxjzXJksOdvJkbbH5fFLifCG5di9rzz3zM8c6HQk dpxbU9ZLF78w== X-IronPort-AV: E=Sophos;i="5.73,380,1583193600"; d="scan'208";a="34195023" Received: from sea32-co-svc-lb4-vlan2.sea.corp.amazon.com (HELO email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com) ([10.47.23.34]) by smtp-border-fw-out-9101.sea19.amazon.com with ESMTP; 11 May 2020 12:36:49 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1d-474bcd9f.us-east-1.amazon.com (Postfix) with ESMTPS id 5E2E3A2340; Mon, 11 May 2020 12:36:38 +0000 (UTC) Received: from EX13D31EUA001.ant.amazon.com (10.43.165.15) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 11 May 2020 12:36:37 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.253) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 11 May 2020 12:36:22 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v11 06/16] mm/damon: Split regions into 3 subregions if necessary Date: Mon, 11 May 2020 14:32:52 +0200 Message-ID: <20200511123302.12520-7-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200511123302.12520-1-sjpark@amazon.com> References: <20200511123302.12520-1-sjpark@amazon.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.161.253] X-ClientProxiedBy: EX13D06UWC001.ant.amazon.com (10.43.162.91) To EX13D31EUA001.ant.amazon.com (10.43.165.15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: SeongJae Park Suppose that there are a very wide and cold region and a hot region, and both regions are identified by DAMON. And then, the middle small region inside the very wide and cold region becomes hot. DAMON will not be able to identify this new region because the adaptive regions adjustment mechanism splits each region to only two subregions. This commit modifies the logic to split each region to 3 subregions if such corner case is detected. Suggested-by: James Cameron Signed-off-by: SeongJae Park --- mm/damon.c | 51 ++++++++++++++++++++++++++++++++++----------------- 1 file changed, 34 insertions(+), 17 deletions(-) diff --git a/mm/damon.c b/mm/damon.c index cec946197e13..fbf37df841ce 100644 --- a/mm/damon.c +++ b/mm/damon.c @@ -650,26 +650,32 @@ static void damon_split_region_at(struct damon_ctx *ctx, damon_insert_region(new, r, damon_next_region(r)); } -/* Split every region in the given task into two randomly-sized regions */ -static void damon_split_regions_of(struct damon_ctx *ctx, struct damon_task *t) +/* Split every region in the given task into 'nr_subs' regions */ +static void damon_split_regions_of(struct damon_ctx *ctx, + struct damon_task *t, int nr_subs) { struct damon_region *r, *next; - unsigned long sz_orig_region, sz_left_region; + unsigned long sz_region, sz_sub = 0; + int i; damon_for_each_region_safe(r, next, t) { - sz_orig_region = r->vm_end - r->vm_start; - - /* - * Randomly select size of left sub-region to be at least - * 10 percent and at most 90% of original region - */ - sz_left_region = ALIGN_DOWN(damon_rand(1, 10) * sz_orig_region - / 10, MIN_REGION); - /* Do not allow blank region */ - if (sz_left_region == 0 || sz_left_region >= sz_orig_region) - continue; - - damon_split_region_at(ctx, r, sz_left_region); + sz_region = r->vm_end - r->vm_start; + + for (i = 0; i < nr_subs - 1 && + sz_region > 2 * MIN_REGION; i++) { + /* + * Randomly select size of left sub-region to be at + * least 10 percent and at most 90% of original region + */ + sz_sub = ALIGN_DOWN(damon_rand(1, 10) * + sz_region / 10, MIN_REGION); + /* Do not allow blank region */ + if (sz_sub == 0 || sz_sub >= sz_region) + continue; + + damon_split_region_at(ctx, r, sz_sub); + sz_region = sz_sub; + } } } @@ -687,14 +693,25 @@ static void kdamond_split_regions(struct damon_ctx *ctx) { struct damon_task *t; unsigned int nr_regions = 0; + static unsigned int last_nr_regions; + int nr_subregions = 2; damon_for_each_task(ctx, t) nr_regions += nr_damon_regions(t); + if (nr_regions > ctx->max_nr_regions / 2) return; + /* If number of regions is not changed, we are maybe in corner case */ + if (last_nr_regions == nr_regions && + nr_regions < ctx->max_nr_regions / 3) + nr_subregions = 3; + damon_for_each_task(ctx, t) - damon_split_regions_of(ctx, t); + damon_split_regions_of(ctx, t, nr_subregions); + + if (!last_nr_regions) + last_nr_regions = nr_regions; } /* -- 2.17.1