From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE7632F4A14 for ; Wed, 11 Mar 2026 13:11:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773234677; cv=none; b=eIplc2/cOmVQ65cE+vl1yT8Tcfyjkrxl4oP9mzH0sbTu56Qk1mESsh88FkTVT0fcioxs0HZ4Sh2kCTx9LPl5IdQE16EP/CKlUIdyhRfGCsBWn664jHpq56LZmc3Rmw8pQEzlSOVBnbpPqu/fS26Ituy+ahSBEr4RFwlKUk0JWDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773234677; c=relaxed/simple; bh=R4WSLec3kNaoCTi/RDjqiyY0W6wWpnHoxb7mZ0ae5gs=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=ZsyyVo0dKUbQE7ighs9OEcfBhv9Vyd6fmH3dRhWsJeHEnAxwEAKTEdj5Zv3dWQvRNEsFuQvJLACly4cqZkiqASDFZpceHvfv/P9Bt/i26da+PTlmiurWQMldNIZpMW/gs5G3vuO2XAyO50qhdep1rgtqd9sy0zT+cUUvoMYoEFU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei-partners.com; spf=pass smtp.mailfrom=huawei-partners.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei-partners.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei-partners.com Received: from mail.maildlp.com (unknown [172.18.224.83]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4fWB1v2vZKzJ46Yd; Wed, 11 Mar 2026 21:10:27 +0800 (CST) Received: from mscpeml500003.china.huawei.com (unknown [7.188.49.51]) by mail.maildlp.com (Postfix) with ESMTPS id A1FA440086; Wed, 11 Mar 2026 21:11:13 +0800 (CST) Received: from [10.123.123.154] (10.123.123.154) by mscpeml500003.china.huawei.com (7.188.49.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 11 Mar 2026 16:11:13 +0300 Message-ID: <0c3068da-4dcb-4bc7-a762-2f529cb5abc2@huawei-partners.com> Date: Wed, 11 Mar 2026 16:11:12 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 2/4] mm/damon: Support for synchrounous huge pages collapse To: SeongJae Park CC: , , , , , , , , References: <20260311010222.90548-1-sj@kernel.org> Content-Language: en-US From: Gutierrez Asier In-Reply-To: <20260311010222.90548-1-sj@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: mscpeml500003.china.huawei.com (7.188.49.51) To mscpeml500003.china.huawei.com (7.188.49.51) On 3/11/2026 4:02 AM, SeongJae Park wrote: > On Tue, 10 Mar 2026 16:24:18 +0000 wrote: > >> From: Asier Gutierrez > > Please add more descriptions of the change, including the motivation. > > I assume the motivation is similar to MADV_COLLAPSE that aims to make > synchronous and therefore faster huge page collapsing impacts copared to > MADV_HUGEPAGE? It would be nice to make it clear here. Also, if my assumption > is not wrong, adding a test results showing the benefit of DAMOS_COLLAPSE over > DAMOS_HUGEPAGE here would be nice. You are right. I will make it more clear in the cover letter for the next version. > >> >> Signed-off-by: Asier Gutierrez >> Co-developed-by: Anatoly Stepanov >> --- >> include/linux/damon.h | 1 + >> mm/damon/vaddr.c | 3 +++ >> 2 files changed, 4 insertions(+) >> >> diff --git a/include/linux/damon.h b/include/linux/damon.h >> index a4fea23da857..a9cf17b9e8fa 100644 >> --- a/include/linux/damon.h >> +++ b/include/linux/damon.h >> @@ -142,6 +142,7 @@ enum damos_action { >> DAMOS_LRU_DEPRIO, >> DAMOS_MIGRATE_HOT, >> DAMOS_MIGRATE_COLD, >> + DAMOS_COLLAPSE, >> DAMOS_STAT, /* Do nothing but only record the stat */ >> NR_DAMOS_ACTIONS, >> }; >> diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c >> index 729b7ffd3565..36791a9a1094 100644 >> --- a/mm/damon/vaddr.c >> +++ b/mm/damon/vaddr.c >> @@ -969,6 +969,9 @@ static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx, >> case DAMOS_NOHUGEPAGE: >> madv_action = MADV_NOHUGEPAGE; >> break; >> + case DAMOS_COLLAPSE: >> + madv_action = MADV_COLLAPSE; >> + break; >> case DAMOS_MIGRATE_HOT: >> case DAMOS_MIGRATE_COLD: >> return damos_va_migrate(t, r, scheme, sz_filter_passed); >> -- >> 2.43.0 > > The code looks good to me. > > > Thanks, > SJ > > [...] > -- Asier Gutierrez Huawei