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=-9.8 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,URIBL_BLOCKED, 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 BA548C47258 for ; Tue, 5 May 2020 11:11:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 965D9206D7 for ; Tue, 5 May 2020 11:11:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="s/xuDIcE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728865AbgEELLL (ORCPT ); Tue, 5 May 2020 07:11:11 -0400 Received: from smtp-fw-33001.amazon.com ([207.171.190.10]:14616 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728689AbgEELLK (ORCPT ); Tue, 5 May 2020 07:11:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1588677071; x=1620213071; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=TKgQmoq0qPNsadPuOq3WWml7xxrCQ3BmjP+Fo2xEHow=; b=s/xuDIcEzV882r+ySNBk8XRr/WdTbHmMX8gqkbIMN2IEqa+yXYAxDAe6 C5k5/KKxU0L4hvangbahHGNvEv8WKvMQD5ONDKCQl9nDk0jJcWE2s175Y 5EXTX9At64bfxWLFCkxR1eWFpevXQvTNYizuvbaEAy9vbDB0p3zNOTpEW I=; IronPort-SDR: sI+Jet086vj+evGLez67MFVCcTXZIdRMxpHDo/o8B1c2Sc/+ApqRXx4p+daesEXDSehJx8GVqc jqMYCny2pSoQ== X-IronPort-AV: E=Sophos;i="5.73,354,1583193600"; d="scan'208";a="42752730" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2a-119b4f96.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 05 May 2020 11:11:10 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-119b4f96.us-west-2.amazon.com (Postfix) with ESMTPS id 53BFE1A0A61; Tue, 5 May 2020 11:11:07 +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; Tue, 5 May 2020 11:11:06 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.160.92) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 5 May 2020 11:10:51 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v10 06/16] mm/damon: Split regions into 4 subregions if possible Date: Tue, 5 May 2020 13:08:05 +0200 Message-ID: <20200505110815.10532-7-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200505110815.10532-1-sjpark@amazon.com> References: <20200505110815.10532-1-sjpark@amazon.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.160.92] X-ClientProxiedBy: EX13D35UWB004.ant.amazon.com (10.43.161.230) 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 4 subregions if possible so that such problematic region can eventually identified. Suggested-by: James Cameron Signed-off-by: SeongJae Park --- mm/damon.c | 44 +++++++++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/mm/damon.c b/mm/damon.c index cec946197e13..342f905927a0 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 +693,18 @@ static void kdamond_split_regions(struct damon_ctx *ctx) { struct damon_task *t; unsigned int nr_regions = 0; + 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 (nr_regions < ctx->max_nr_regions / 4) + nr_subregions = 4; + damon_for_each_task(ctx, t) - damon_split_regions_of(ctx, t); + damon_split_regions_of(ctx, t, nr_subregions); } /* -- 2.17.1