From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6DDA03F484B; Wed, 12 Aug 2026 08:58:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786525135; cv=none; b=clXTGJb4CGqjCjRyWEi4teL2QfjwF9gzc9kY4khaUw8kyYKgyhblD1bkzyEiXwYC+q0OjrFuSBNFdHAgH4im8HTB50rq1bPdxtUSyTvJ3HlM6OKOkZHGu3i3PfGNvyX20UGDnyqsZh/+tlbqkImtHzqLqd5eLnRFxx2RxM3SDh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786525135; c=relaxed/simple; bh=Wh0KA3Ab43Gft7XkMtU2UVjIfzcxtWxFpaBBvXzBFmo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AAPjNp3SID6aC25echqOWhGhGc7N8k1wTBYGtoKzHeefIithnnEpNJGtl4jV2mY/wo5iVIDojjLfPuMl1C3zkOxv2CdZvPsBEY5omO1ROAG+HgM8sCe7HnuImt1MqHMd7Itrw5gGOExqOWNq2tPw78jqKVBJMFvE414Fx3n7CM0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oaAm6ZoL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oaAm6ZoL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45FF41F000E9; Wed, 12 Aug 2026 08:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786525134; bh=Lv+2Z/1Wduwhy5AzrXisK5gs2st/FQotGoYG6sp0EPg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=oaAm6ZoL0bGjZNnnDPIJ7BXckZpQ3BmpgPnW5gWbYQfp7gpAkJNt7lLc+JWkrobJn brbcqfuvNBIv9dWGRsvq7NaFzyKYSvtcA2/8a94AHmaMA2JWt+y0hwvPw24TtPQBoC hLPYaqBg2GMJg7oJ5SWcWjj7huO84D6OKabzAxEKGI6uFbYT7oCrAkt1d+FuRG6KhG SDUGkoKUPa8OQhqp3rSW2FAQ8h/H0FGSWNdL/F+eP00BJ6sfSLNVvY3PjdpC9phucQ MX8Bbtq0Ra45++zyGyAZpYMm7RwgR/q+Ve4aMEGj65gnhNnCoCe4f9D6z+txZcM+nU TeJQCS0LT9DXQ== Date: Wed, 12 Aug 2026 09:58:33 +0100 From: "Lorenzo Stoakes (ARM)" To: Song Hu Cc: linux-mm@kvack.org, akpm@linux-foundation.org, david@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] Docs/ABI: document transparent_hugepage/shrink_underused Message-ID: References: <20260812080313.330413-1-husong@kylinos.cn> <20260812080313.330413-2-husong@kylinos.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260812080313.330413-2-husong@kylinos.cn> Please don't send patch series like this - we really require a cover letter if patch count > 1, and every patch should reply to the cover letter. On Wed, Aug 12, 2026 at 04:03:12PM +0800, Song Hu wrote: > The shrink_underused knob was added in commit 81d3ff3c6f76 ("mm: add > sysfs entry to disable splitting underused THPs") but is missing from > Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage, although > transhuge.rst already documents it. Add the ABI entry. Hmm what even is this file? :) What is the contract on this file? > > Signed-off-by: Song Hu > --- > .../ABI/testing/sysfs-kernel-mm-transparent-hugepage | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage > index 7bfbb9cc2c11..bbdfae2c0caa 100644 > --- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage > +++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage > @@ -10,9 +10,19 @@ Description: > - hpage_pmd_size > - khugepaged > - shmem_enabled > + - shrink_underused I mean I guess fine for consistency. > - use_zero_page > - subdirectories of the form hugepages-kB, where > is the page size of the hugepages supported by the kernel/CPU > combination. But we already handwave literally everything else here.... > > See Documentation/admin-guide/mm/transhuge.rst for details. > + > +What: /sys/kernel/mm/transparent_hugepage/shrink_underused > +Date: Sep 2024 > +Contact: Linux memory management mailing list > +Description: Reading and writing this file controls whether khugepaged > + splits underused transparent huge pages (THPs) under memory > + pressure. A THP is considered underused when its number of > + zero-filled pages is above max_ptes_none. Enabled by default; > + writing 0 disables the splitting and 1 enables it. Nothing else is documented in this file so why is this getting special treatment? And why is it backdated to Sep 2024?... Drop it please. > -- > 2.43.0 > -- Cheers, Lorenzo