From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 868B21A6817; Wed, 11 Mar 2026 01:02:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773190945; cv=none; b=h1h0ixXkRzvGossWHWTAkjhkMuintcfhR0klU6lSi8x5V0+j4+HLemxnJ6zYNUIIvm6qxulO8d0oPGcmli2vOMPOG2vuflcHuoXE1T6DVTNk8cu7IA4dNu+gluR2+ty2A8W/I2RzXcAaZWs7x8K2sZpIoUs9xOG7ukkeMt2Q1Lw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773190945; c=relaxed/simple; bh=we4i7ziZO6kLsqvcAHMYtzXyERLCpQSm8acjuSSDEvg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QyuYOfxS+V1VaJiFHyEwUsneHnh5N/tDXPeWfuuGfnGDGVONoAY+hoVecd/nJY5ni4hfPkOuPhTj8L2vIev3J38lZlOEH3ve6bpiQGAA5vOovEtSboHuYTx/3d4u3H/+2Rz0Q7ryCH/cU/x6NkwoI8c99XeqH1eb5MC87/z/K9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DDJ39niq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DDJ39niq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8B8DC19423; Wed, 11 Mar 2026 01:02:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773190945; bh=we4i7ziZO6kLsqvcAHMYtzXyERLCpQSm8acjuSSDEvg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DDJ39niqZe2VuO/AOLrzUooRI8Kka+AUG+I1QqX+ccRej9XGpX1EbT70usNhhk0WH 3Hu1gO3Ih1pLLyIG5cjeuauIWOpNPoeNBimlhBzm5QQn83fZQ4LEjsJahWO3pg2IBG d30nTWCiO7p4rjwOuPX9iWX3LM2+YsfD51tEFGridpXeu1HHs2AId1rxRc/7st1xtH Ry6XiQ2Y6xcEi+GZAo3TlYGrvKP1Xx7rhkNulXHlZxZXAelXAkKYShnmXXZjcV5QWq UENkuT2Noc7TmRmYMZ+/Y3TAjnZ32LzBvpgcmcA4px9sZ9QEMRYqpxH7t9TVwSz9dg zKGepBss2dzGw== From: SeongJae Park To: gutierrez.asier@huawei-partners.com Cc: SeongJae Park , artem.kuzin@huawei.com, stepanov.anatoly@huawei.com, wangkefeng.wang@huawei.com, yanquanmin1@huawei.com, zuoze1@huawei.com, damon@lists.linux.dev, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 2/4] mm/damon: Support for synchrounous huge pages collapse Date: Tue, 10 Mar 2026 18:02:21 -0700 Message-ID: <20260311010222.90548-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260310162420.4180562-3-gutierrez.asier@huawei-partners.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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. > > 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 [...]