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 73F034A3F13; Tue, 8 Sep 2026 10:18:00 +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=1788862681; cv=none; b=BwZLgGXCrhjKY1KYoCymnWZ6ynO5RDgqvpkzD95RGU7VEXGPpDpmoeF/26zk577CfUK08LNGLTUjgMf2Bgk392x7v0CJqkmcZZV/DnjhFL/O8R5+PqVRRGfwqXbjK2A5bcG1fX3R/06Gh3HzuRCpbFkSZpGUKT9mG+XpZSLbkig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788862681; c=relaxed/simple; bh=REefT6Y4BF9qgcV86uQSOz0t9HuJ3hYnZlBIuoh/3Xs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=T9GWmP1pahoRyAe0xGj1oO8yWbG4qPYTF6Z3HnR3iBocIq6ninB2g+ONE6oBVVsaujpvN3YOmiOHTTz2meCOkJBYZ3VcCq77HdMnD0/ESIXNdGeDaIswjcb4JPU9ue2REjNAmRg/5yYDtuUO0/wiMZ3XSejtMRlODXbhTelQAn8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MwavFRK/; 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="MwavFRK/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 798C01F00A3A; Tue, 8 Sep 2026 10:17:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788862680; bh=1BUq9DqNfvFJpJpxO4ESAHte1Bx4yrvo0vCrnSZ9Wno=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MwavFRK/ztSyhXEhkjmbGgqiZw9sxr6mV1TbmhsRFf12TB/TYGglIbkUGeV7tUtxg F148rzwylaMteqXTQlfgqCpYKWA3xLRuiSk/6ZuEdUVkyxHT5HaPDlNP0bbVm6Mp4p FjSWVQUHDyaswMIHtvx1lOd10oe48Ss+ENBMUdnmWGrLP856Z/MdRVE992y9WKpPde +MjO72CMnbl+RMjRI6UWUrE7V/VLv19l77g/zVYAe07/V28dqEfQXF1MRWhBgAn38K WdW1TZooWTeccR2yS/OgrcO2v9FkbaEz0BGcv51hlHvuCPSmslvFgE1NzbkgrltoCJ qqFQ5EJFaso2A== Date: Tue, 8 Sep 2026 13:17:50 +0300 From: Mike Rapoport To: Thierry Reding Cc: Vincent Donnefort , catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, sudeep.holla@kernel.org, jenswi@kernel.org, robh@kernel.org, mark.rutland@arm.com, sumit.garg@kernel.org, ardb@kernel.org, david@kernel.org, danielmentz@google.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 01/10] memblock: Introduce MEMBLOCK_LLMAP Message-ID: References: <20260902104712.2399797-1-vdonnefort@google.com> <20260902104712.2399797-2-vdonnefort@google.com> 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: On Tue, Sep 08, 2026 at 11:18:53AM +0200, Thierry Reding wrote: > On Tue, Sep 08, 2026 at 10:40:16AM +0300, Mike Rapoport wrote: > > On Mon, Sep 07, 2026 at 10:50:12AM +0100, Vincent Donnefort wrote: > > > On Sun, Sep 06, 2026 at 10:33:11PM +0300, Mike Rapoport wrote: > > > > On Wed, Sep 02, 2026 at 11:47:03AM +0100, Vincent Donnefort wrote: > > > > > Keeping last-level mappings is interesting on some architectures as it > > > > > allows mapping/unmapping pages from the kernel direct map without the > > > > > risk of splitting blocks which, under the break-before-make rule, may > > > > > trigger page-faults the kernel can't handle. > > > > > > > > > > However, mapping the entire direct map at PTE-level is costly. So > > > > > instead, create a new memblock flag MEMBLOCK_LLMAP to enable the system > > > > > > > > I believe MEMBLOCK_PTE_MAP sounds more descriptive. > > > > > > The idea was to have something close from NOMAP, to emphasis it is one or the > > > other. But PTE_MAP sounds good too. > > > > Could be PTEMAP if you prefer. > > My point was that unlike PTE, "LL" is not perceived as last-level, it > > should be looked up. > > We were discussing the concept of enabling entire block mappings to be > removed at once from the linear map, so at that point "PTE"MAP may no > longer be accurate. > > I imagine that in some scenarios we might be able to go to PUD mappings > for something like VPR (say systems with a fair amount of system memory > and we want to carve out 4 GiB for VPR, split into four 1 GiB chunks). _LEAFMAP then? ;-) > Thierry -- Sincerely yours, Mike.