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 58559284665 for ; Sun, 8 Feb 2026 18:07:33 +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=1770574053; cv=none; b=bbPkgZm3a0nxkd3PPV6LKiBupKXSe3+vXrTirRDZykOVFmOYPiNdUAgS3sBdU6QOaUtt9dzSDl7Lxz1ZyFQqeYu44v7cs12yo2VbSiN75Lm4wraKFKf7XnqyBli5+c6I/MXXJeUl2NMkFPc5J10OfsvMW0KvIe0AGmpdehexbxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770574053; c=relaxed/simple; bh=PxcXwLUBRw69pj0y/iw2r5Y8so1kEeFr6i4iz7h+PcY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GenmbPJmhKXx4tlEE/QmAaxSSf6Shr8O/xKAXl8Ea4idHnJ7xWL1AygyuabwmpyGfSLIT39YtZnjG8sn87UHuQukr2PYpFjizYXBjD8v89QrGnlMN4mu9GRMGROQkaMz+iezMxflaeSBGgp+10w6dvSjqwaBETJ1XZAixIkotQM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eIjSMF/3; 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="eIjSMF/3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 158FAC4CEF7; Sun, 8 Feb 2026 18:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770574053; bh=PxcXwLUBRw69pj0y/iw2r5Y8so1kEeFr6i4iz7h+PcY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eIjSMF/3JMss8Yv+gzQCRJWnr30dkiCVPZJUb/Twq/rYj3Ce0b2P3ZsnTT+JbZyka vlOgGbPj+Hs+7evu4WQ5ZZjNMTbLg8eophnbVM8l5Yw9ZGiNNRYPAhr1wZw7Mnbbjp s2KPl5J79HQ1SNpCBVRfzZ5+IMwcNfGdFOgsV3UiLeNGfPu/PNNdp4cUxruGUrFEv4 wvtSKOjCooDTcqBbHi/diKNhFZrcnm2EgIxJKYeJivAggYo04X0Rr5a4R6B9kAT3/m 7midGG2ywBRApW/wuU82yzTseJINdxFPeWtLzn+sGRIQ3Xm9/dKr0cw8XkzCYvxSLP yE1Cl6ejYcP8g== Date: Sun, 8 Feb 2026 20:07:25 +0200 From: Mike Rapoport To: Jason Miu Cc: Alexander Graf , Andrew Morton , Baoquan He , Changyuan Lyu , David Matlack , David Rientjes , Jason Gunthorpe , Pasha Tatashin , Pratyush Yadav , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v9 1/2] kho: Adopt radix tree for preserved memory tracking Message-ID: References: <20260206021428.3386442-1-jasonmiu@google.com> <20260206021428.3386442-2-jasonmiu@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: <20260206021428.3386442-2-jasonmiu@google.com> On Thu, Feb 05, 2026 at 06:14:27PM -0800, Jason Miu wrote: > Introduce a radix tree implementation for tracking preserved memory > pages and switch the KHO memory tracking mechanism to use it. This > lays the groundwork for a stateless KHO implementation that eliminates > the need for serialization and the associated "finalize" state. > > This patch introduces the core radix tree data structures and > constants to the KHO ABI. It adds the radix tree node and leaf > structures, along with documentation for the radix tree key encoding > scheme that combines a page's physical address and order. > > To support broader use by other kernel subsystems, such as hugetlb > preservation, the core radix tree manipulation functions are exported > as a public API. > > The xarray-based memory tracking is replaced with this new radix tree > implementation. The core KHO preservation and unpreservation functions > are wired up to use the radix tree helpers. On boot, the second kernel > restores the preserved memory map by walking the radix tree whose root > physical address is passed via the FDT. > > The ABI `compatible` version is bumped to "kho-v2" to reflect the > structural changes in the preserved memory map and sub-FDT property > names. This includes renaming "fdt" to "preserved-data" to better > reflect that preserved state may use formats other than FDT. > > Signed-off-by: Jason Miu Reviewed-by: Mike Rapoport (Microsoft) -- Sincerely yours, Mike.