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 3B84C3B47E3 for ; Wed, 1 Jul 2026 20:07:02 +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=1782936424; cv=none; b=FekvzxsbnxvzZGkwB8y87IW3WSMIYynW/aJTDD+uYymKcWVsx8psjVNORqQJdBq4gWUxA0rkb/rJFH51yAOnXwc5spnjjLEmEuXKmNJHjQPhvz2pqjADza2Aw3du05LIQXgepQh/eR5pf49V34TEvkcuYRvrtQHc2dVINwvAg54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782936424; c=relaxed/simple; bh=P7TkyX8nh4MNMFB3u8Af9jv8pOqh+QJOI6Bg+Yb9ogk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kw6JTB+J6jiX6q5ttiauFU65jm+NqwXr8byrw/lh2ZjBgdyFCi5jTkzi8iuHoDVrfFwAL24Hti8PYh9or3v6yzvPuVMKM9yGme+jZX2mdAm7F6hLLXUV+M04O15/NelZ9AdEzqZ8cyoQz4FeP2ofrtjfkROblfrYwxCXIDLqPV4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Claj4dMc; 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="Claj4dMc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FEC01F000E9; Wed, 1 Jul 2026 20:06:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782936422; bh=JlvkbBWp+nCtDdzWKMgtdcXUqu08ewyXUHePXK7va7c=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Claj4dMcTgt01vsBm9pIoz3ZxkgeC/HuvGWH8eDcEAu8t5aWHSbTv5N1vZqpPXUpE +OsxvcENS2GHHiA3KNoQT55kEzk8C9B5oyPPmiYpmsWwVJD+5AACL9RJ9PTfGTxcBn 9uzK8+S6uzC6CkmNmqOykqeZCTk4rjcrDfCnz7uSpwfxjkdDCr12R/1UQNoxj7q7up jBH7OIOA9PkY2P9lU5aSkyGRlcu88eRBPvumPHKLnmR3KmomqF/dS1O9RtFsCu8gZ4 lGmomMJA44wv1Pyqse5gqMrIYnvBQZUx1xzuqRngnqBStmcO4vfSMwyaAERoqbny3B 68UO/kwgYXaow== Message-ID: Date: Wed, 1 Jul 2026 22:06:57 +0200 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: [PATCH] mm/migrate_device: pin large folios before splitting To: Andrew Morton , Zi Yan Cc: Usama Arif , apopple@nvidia.com, byungchul@sk.com, gourry@gourry.net, joshua.hahnjy@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, matthew.brost@intel.com, rakie.kim@sk.com, ying.huang@linux.alibaba.com, shakeel.butt@linux.dev, hannes@cmpxchg.org, kernel-team@meta.com, sashiko-bot References: <20260701140638.840773-1-usama.arif@linux.dev> <78C557ED-3CF3-4558-9BA4-C43B30E63F67@nvidia.com> <20260701122745.2bfab3347691b658fb93f601@linux-foundation.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/1/26 21:27, Andrew Morton wrote: > On Wed, 01 Jul 2026 13:02:10 -0400 Zi Yan wrote: > >> LGTM. Like David said, the comments might not be needed. Thanks. > > I like the comments! They may be uninteresting to those who are > already familiar with these things, but they aren't the target audience. > > How are others to become familiar, if not by this? I mean, it's one of the basic rules: if you lookup a page in the page table, the moment you drop the lock that might be invalid. If we were to document that everywhere... this is not really the secret sauce we want to document everywhere. -- Cheers, David