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=-9.9 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 DBAC7C433E1 for ; Mon, 18 May 2020 10:05:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B649F20801 for ; Mon, 18 May 2020 10:05:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="QHkYza8I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726918AbgERKFV (ORCPT ); Mon, 18 May 2020 06:05:21 -0400 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:49652 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726274AbgERKFU (ORCPT ); Mon, 18 May 2020 06:05:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1589796320; x=1621332320; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=fovQ16L+stcdrxZLgubG+D9JSvkNCqpwdVSTbsWqGSk=; b=QHkYza8IY5WYYXJDNDB8/L6PyG4bK6CM1+DlfvY73ZaJXj2Be9TWsz9/ ADpbaU+y06sXcnRro5NhsJxaJkXQCh0XjYQp6GGSj1obGFuEZVV5RutOo Yu0h77JxA9Dyga8tRKMFI5rDn5Yj8cHRXv/eRs1c3wp1W86ZTlV57qOAq w=; IronPort-SDR: 3lposJMuKVyCpsEMqUrjgdlwAlAVRHMJKcJp84bC+EwnzqvOmPc8k5/eixyb14KMVKVdswhMHl IQvKAmHLs2jQ== X-IronPort-AV: E=Sophos;i="5.73,406,1583193600"; d="scan'208";a="44034842" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-1a-16acd5e0.us-east-1.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP; 18 May 2020 10:05:16 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1a-16acd5e0.us-east-1.amazon.com (Postfix) with ESMTPS id F3738A24A3; Mon, 18 May 2020 10:05:04 +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, 18 May 2020 10:05:04 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.160.90) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 18 May 2020 10:04:48 +0000 From: SeongJae Park To: CC: SeongJae Park , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v12 06/16] mm/damon: Split regions into 3 subregions if necessary Date: Mon, 18 May 2020 12:00:08 +0200 Message-ID: <20200518100018.2293-7-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200518100018.2293-1-sjpark@amazon.com> References: <20200518100018.2293-1-sjpark@amazon.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.160.90] X-ClientProxiedBy: EX13D04UWA003.ant.amazon.com (10.43.160.212) 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 6c9581104caf..bbd5b1d921da 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(t, ctx) 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(t, ctx) - 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