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 56A55C77B7C for ; Thu, 3 Jul 2025 05:18:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E4E43900004; Thu, 3 Jul 2025 01:18:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DD6AF8E0002; Thu, 3 Jul 2025 01:18:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC76A900004; Thu, 3 Jul 2025 01:18:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id BC99B8E0002 for ; Thu, 3 Jul 2025 01:18:46 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 8F0841A06A7 for ; Thu, 3 Jul 2025 05:18:46 +0000 (UTC) X-FDA: 83621798652.24.10BE248 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by imf10.hostedemail.com (Postfix) with ESMTP id A2F4FC0005 for ; Thu, 3 Jul 2025 05:18:44 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; spf=pass (imf10.hostedemail.com: domain of yunjeong.mun@sk.com designates 166.125.252.92 as permitted sender) smtp.mailfrom=yunjeong.mun@sk.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1751519925; a=rsa-sha256; cv=none; b=kGO9+9dpuzt+Acf0/jgRazDZlkbkwhEAZHt+zq9AFwiFMfAXuovfgfhBCAgdNbtiLRB6nj GvWe5kTbBiG+A4mEzFhO7tYd9SwtiBSp/ItSnlwcika3zI/bPs4Ut0DKLxPiGDNs2r9gcJ mQxhw0e+fhMzXgWpqgfajZ35IQq7duU= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf10.hostedemail.com: domain of yunjeong.mun@sk.com designates 166.125.252.92 as permitted sender) smtp.mailfrom=yunjeong.mun@sk.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1751519925; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tKmMaV0LpZk/UvcGgg482gdCdwKbhGVW7EhoYBlXquE=; b=MMbaFl2ld15ydDo3tNmkFbT6ZMDPVQ6DYIjzV+7MAw2vRHGarBhxSwsaRxEb7KqnajQYH8 f+RrS+lw5uUYuar3pELlY1BOPqnm8bBs74vurbTA8AJTsLRmE97ddTYDcHkXRgK+xIwFOy KKVzYLlNOMPGlLpy1JZjV0mkWVGrPLY= X-AuditID: a67dfc5b-681ff7000002311f-eb-686612af9c20 From: Yunjeong Mun To: sj@kernel.org Cc: akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel_team@skhynix.com, honggyu.kim@sk.com Subject: Re: [RFC PATCH 2/2] samples/damon: add `migrate_hot` and `migrate_cold` knobs Date: Thu, 3 Jul 2025 14:18:34 +0900 Message-ID: <20250703051836.1759-2-yunjeong.mun@sk.com> X-Mailer: git-send-email 2.48.1.windows.1 In-Reply-To: <20250702000825.57587-1-sj@kernel.org> References: <20250703051836.1759-1-yunjeong.mun@sk.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrGLMWRmVeSWpSXmKPExsXC9ZZnke56obQMg7uHrS3mrF/DZvHk/29W i8u75rBZ3Fvzn9Xi8Nc3TA6sHptWdbJ5bPo0id3jxIzfLB4vNs9k9Pi8SS6ANYrLJiU1J7Ms tUjfLoEr4/rGT0wFv4QqLkz4wNLA+IKvi5GTQ0LARGJt33oWGPvFp39gNpuAhsTBQyeZQWwR AUGJ/sczWLsYuTiYBeYyShw5854RJCEsECZx7cdmJhCbRUBV4uuyNWDNvALmEktWnGOEGKop 0XDpHlgNp4CxxPvlzawgthBQzb3V39gg6gUlTs58AtbLLCAv0bx1NjNE7ww2ibvLwiBsSYmD K26wTGDkn4WkZRaSlgWMTKsYhTLzynITM3NM9DIq8zIr9JLzczcxAkNzWe2f6B2Mny4EH2IU 4GBU4uF1kE/NEGJNLCuuzD3EKMHBrCTCyyebnCHEm5JYWZValB9fVJqTWnyIUZqDRUmc1+hb eYqQQHpiSWp2ampBahFMlomDU6qBcVGsle8+3hiBFa2lVe8ypS6Y8UYXPt6z6JDN7ShRjx/m 58TOM1d+kb6c4rZ5kcCGjyvmX8u0riqOUt5oH9x+RtVUU0ZykV1x5vwER6dny9d9vSuX1Dff d+fczxeX8EvVZKR9teB3vPYlxYTRuWu3cN9vzhmqqezSQq8ERTS/TEgWWKF59EuhEktxRqKh FnNRcSIA+we2fkkCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrOLMWRmVeSWpSXmKPExsXCNUNWR3e9UFqGwbIeQ4s569ewWTz5/5vV 4vOz18wWh+eeZLW4vGsOm8W9Nf9ZLQ5/fcPkwO6xaVUnm8emT5PYPU7M+M3i8WLzTEaPb7c9 PBa/+MDk8XmTXAB7FJdNSmpOZllqkb5dAlfG9Y2fmAp+CVVcmPCBpYHxBV8XIyeHhICJxItP /1hAbDYBDYmDh04yg9giAoIS/Y9nsHYxcnEwC8xllDhy5j0jSEJYIEzi2o/NTCA2i4CqxNdl a8CaeQXMJZasOMcIMVRTouHSPbAaTgFjiffLm1lBbCGgmnurv7FB1AtKnJz5BKyXWUBeonnr bOYJjDyzkKRmIUktYGRaxSiSmVeWm5iZY6pXnJ1RmZdZoZecn7uJERh8y2r/TNzB+OWy+yFG AQ5GJR5eB/nUDCHWxLLiytxDjBIczEoivHyyyRlCvCmJlVWpRfnxRaU5qcWHGKU5WJTEeb3C UxOEBNITS1KzU1MLUotgskwcnFINjCsmxzF07I44vuXohfB/PGp6vHPtuJ4tZtwlt5BhQYGk Y+0czkXiApIhjN7WCcvbav3DOj7U3zK6uMzgVf7uM/Msvzf/6X7OdWymq5d1q9qUPSXuri6m M3Pm7XaYpboo9+ztgqOcVs5G12Id2BkdaviVH+dIxc1YpbRBvW65qecx284qn+/7lViKMxIN tZiLihMBMInT8ToCAAA= X-CFilter-Loop: Reflected X-Stat-Signature: igh64497nntiphwi4hwh1gxxpmqkyrxw X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: A2F4FC0005 X-Rspam-User: X-HE-Tag: 1751519924-664112 X-HE-Meta: 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 GDcNEDNq SYzBnp8hipYmMovRAvhesGYdpDbct6TFDdWjGxK8IeeUDLFsBUPqowqLoIqyuI/Z2WbCKFIRYYFRkFb4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello SeongJae, On Tue, 1 Jul 2025 17:08:25 -0700 SeongJae Park wrote: > Hello Yunjeong, > > On Tue, 1 Jul 2025 17:54:17 +0900 Yunjeong Mun wrote: > > > This patch introduces two new konbs for promotion/demotion: > > `migrate_hot` and `migrate_cold`. It receives node ids for migration in > > a comma-separated format as ``. The usage is as follows: > > > > # demote pages from nid 0 to nid 1 > > $ echo 0,1 > /sys/module/mtier/parameters/migrate_cold > > # promote pages from nid 1 to nid 0 > > $ echo 1,0 > /sys/module/mtier/parameters/migrate_hot > > I understand you want to support some setups such as having a fast node of id 1 > and a slow node of id 0. > > Because mtier is a sample code, I think it's primary goal is to help developers > know how they can use DAMON API functions for writing kernel code that is > required for a situation similar to the sample. Hence the sample should be > clean and simple enough to be understood. Thanks for explanation. I understand the intention of mtier module. As you mentioned, mtier is helpful for leraning how to configure and run DAMON. > > The assumption of the two nodes (the fast node 0 and the slow node 1) is > arguably intended for making the code simple, in my opinion. We could of > course make this kind of changes if it helps more experiments for understanding > the code, as sample code is not only for reading but also running. > I also think that fast node 0 and the slow node 1 is intuitive and easy to understand the code. > > > > Susggested-by: Honggyu Kim > > checkpatch.pl found a typo: s/Susggest/Suggest/ > > > Signed-off-by: Yunjeong Mun > > --- > > samples/damon/mtier.c | 68 +++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 66 insertions(+), 2 deletions(-) > > But, I feel like this change is rather making code too longer and complicated. > Hence I would suggest dropping this patch if you agree. Please let me know if > you have different opinions, or I'm missing something. > Ok, I will drop this patch in next version RFC. As you mentiond, mtier module should be simple and intuitive enough. I will consider this kind of tiering module to mm/damon. I'll send you RFC v2 soon. Best Regards, Yunjeong Mun > > Thanks, > SJ > > [...]