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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03991C25B0E for ; Fri, 19 Aug 2022 04:52:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 424C68D0003; Fri, 19 Aug 2022 00:52:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3D4728D0002; Fri, 19 Aug 2022 00:52:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C34D8D0003; Fri, 19 Aug 2022 00:52:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 190B88D0002 for ; Fri, 19 Aug 2022 00:52:23 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id DDE8240277 for ; Fri, 19 Aug 2022 04:52:22 +0000 (UTC) X-FDA: 79815120924.13.1A3B92C Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf25.hostedemail.com (Postfix) with ESMTP id 717C4A000E for ; Fri, 19 Aug 2022 04:52:22 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B23F46154E; Fri, 19 Aug 2022 04:52:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFE0FC433D6; Fri, 19 Aug 2022 04:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660884741; bh=pJsR9cSORbtbMymP+m9MvHTaCihfu9PX9SIGrheKZmw=; h=From:To:Cc:Subject:Date:In-Reply-To:From; b=o637CJLbB7MYcFkOf3iJtO6JpyRqT6H/5C4jnwxHKJxPdd8ZbddPbFkBo+Owi/yid XwC+pxHsAnOS7lk8zjN3euHYHC8T1TKW7LPAUZ1VzFVNxyvbUZAJX05KUIX0W0YcTe zutCqedwg2t+ZGWH9IsEbLWKOLFpN1rToKXWL/HQnGuaYzniR+aYnDlfZmHCLur+18 A9rskX98zkia9sdqJOJtmTL37CwwpUIM+SvRSc2c/jGT2ltJtUDi7TTj/YphImTOX8 jIOurMsYjVJ+aDtwDBX0ZqunReNK3u1gU4A8bAOyztUXzd72GBHUkzvSLwyU8v/DGR gBxt8Sf1ZFALQ== From: SeongJae Park To: haoxin Cc: SeongJae Park , akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2 1/2] mm/damon/lru_sort: Move target memory region check to head of func Date: Thu, 18 Aug 2022 21:52:04 -0700 Message-Id: <20220819045204.21834-1-sj@kernel.org> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660884742; a=rsa-sha256; cv=none; b=pb4fScCKOyZu064hOiTr5Z3bE00iItbl6IIlzCx03XQtHgmTNXn4zDkNjSyHLWERUKmRCm Jtn3L+4FulaNOva/jyNU6HCd0zXYQ+/jJ1fLUfPEi0eKR0jiwciEc3Sur9OVG1wdyEX/eZ 0v4UPgp3EacdZn0rx0c4tUft1nsGU2w= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=o637CJLb; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of sj@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660884742; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:dkim-signature; bh=4Io4dj3C2E11Jl8WGfnog72XKbtwSqhrHkij01FChPU=; b=Y/8QdZuISF0XFXnf9WNa5FhFiNT5kJ1HSqXsUr9C/9H3IIijNJlZ4qa59mae/qQh6p9wFF W2r/vsk3R/e4PKk8oqY+e3eYCv3Fbjs6ELV6R2ZwbRCIWR4pDuSoCPUD9My07V6KMJl6r1 DfrIpnDajncyYIhs8/h/rNhb8B35M6k= X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: iunffim1robjf5adtqwn3cttq4jrc39o Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=o637CJLb; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of sj@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sj@kernel.org X-Rspamd-Queue-Id: 717C4A000E X-HE-Tag: 1660884742-740249 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000862, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 19 Aug 2022 10:47:58 +0800 haoxin wrote: > > 在 2022/8/19 上午10:28, SeongJae Park 写道: > > Hi Xin, > > > >> 在 2022/8/19 上午1:11, SeongJae Park 写道: > >>> Hi Xin, > >>> > >>> > >>> On Thu, 18 Aug 2022 18:57:31 +0800 Xin Hao wrote: > >>> > >>>> In damon_lru_sort_apply_parameters(), if "monitor_region_start" > >>>> and "monitor_region_end" is not a valid physical address range, > >>>> There no need to run the remainder codes in it. > >>> The function, 'damon_lru_sort_apply_parameters()', checks validity of > >>> parameters and construct the DAMON context one by one. For example, > >>> 'damon_set_attrs()' returns an error if the parameters are invalid. So the > >>> intended flow is, > >>> > >>> 1. check DAMON attributes parameters, > >>> 2. apply DAMON attributes parameters, > >>> 3. check scheme parameters, > >>> 4. apply scheme parameters, > >>> 5. check target region parameters, and > >>> 6. apply target region parameters. > >>> > >>> Therefore what this patch does is making the target regions validity check to > >>> be done earlier than validity checks of other parameters. There is no special > >>> reason to check the region earlier than others. Also, this change makes the > >>> flow of the function a little bit weird in my humble opinion, as the flow will > >>> be > >>> > >>> 1. check target region parameters, > >>> 2. check DAMON attributes parameters, > >>> 3. apply DAMON attributes parameters, > >>> 4. check scheme parameters, > >>> 5. apply scheme parameters, and > >>> 6. apply target region parameters. > >> Ok, understand what you mean, my fix looks ugly, buy any apply above > >> are not not necessary if one of them checks failed, why not check all > >> fisrt and then apply them, like this: > >> > >> 1. check target region parameters, > >> > >> 2. check DAMON attributes parameters, > >> > >> 3. check scheme parameters, > > The parameter values could be changed by users after the check, so we should > > cache those somewhere anyway. In other words, we cache those in the DAMON > > context. Therefore I think the above works were not totally waste of the time. > > Also, because the parameters applying functions like 'damon_set_attrs()' does > > the check and applying of the parameters together, I feel like current flow is > > natural. > > Ok, Thank you for your detailed explain, just keep it. but there still > a problem in damon_lru_sort_apply_parameters > > if (!monitor_region_start && !monitor_region_end && > !get_monitoring_region(&monitor_region_start, > &monitor_region_end)) > > if (!monitor_region_start || !monitor_region_end || > !get_monitoring_region(&monitor_region_start, > &monitor_region_end)) > > the '&&' should fix to '||', anyone checks fail, it should return ? No. The code is for setting the monitoring region as the biggest System RAM resource only if the user didn't set both 'monitor_region_start' and 'monitor_region_end'. Thanks, SJ