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 3500327B34D for ; Mon, 1 Dec 2025 06:50:30 +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=1764571831; cv=none; b=lENZyFWy+yEIfvdhPJE9GBQ6NeN6rgGbdqOWJHcY35oMVcpfJY+TzFjxBbAETySbHQ77ZVDUgcBTv8pkzukCzZo7VojYrshTWEhhoMZOsKY2bdiSyAxrAsrRAs2bJHE6P3X8k3BuRhPIj17AvtN0j5c/jJnI+QeoTUs7xqgIdXc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764571831; c=relaxed/simple; bh=77kPZg+Fi5iO/CYTWecR13T71hr5HYPvf7lTx+iWO44=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=u93IRnOkkucB4RKlu8/OKHOpx4za6iJPZMjh6Kxt0b9HSsXUY7VNwxTzLY14TH9lE4aK+hilP4EbQAN1IJkbsv3sKbVgukEWsP7cYSAQMrRcUCGMVcmkwNY9Obf1/6gDrhKEL8zT7mNIYE2xRr0RKgWbNoYAVProwFTcDkaym1I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sVk/USQ6; 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="sVk/USQ6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D065C4CEF1; Mon, 1 Dec 2025 06:50:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764571830; bh=77kPZg+Fi5iO/CYTWecR13T71hr5HYPvf7lTx+iWO44=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sVk/USQ64Orrpyfz0mu6ZUa1S1fjZPZtMuDdj5fmZEMCViOctL4J3ASH0iOMb2pJG PkI9LlbNvQz3AuBcYuaVkeh+7rshP+zapdg3gsvXV5S4ViHwAssXWmuYHFshZWRDNJ Nh7RST06ST8IGkG2M0bgQC4JVFHbVztyjtK2ha0bNdb6xffvqcEf+j/Aa6BgqHvfeX eSgxvppJpPiEaO19+AQ/DK6oDxXIpSZcPejCzf0KpfFS26wxcIlb1HVmpCuJrSgBHU LzDa4lk70qAkQ6u1elXClbFjDLIjqGSljol4fZdbDX69nMKSpv3VfvHlpx2R8lump/ FGOeDCGS+G1mg== Date: Mon, 1 Dec 2025 08:50:24 +0200 From: Mike Rapoport To: Swaraj Gaikwad Cc: akpm@linux-foundation.org, david.hunter.linux@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, skhan@linuxfoundation.org Subject: Re: [PATCH RFC] mm/memblock: Fix reserve_mem allocation overlapping KHO scratch regions Message-ID: References: <20251130211540.582343-1-swarajgaikwad1925@gmail.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251130211540.582343-1-swarajgaikwad1925@gmail.com> Hi Swaraj, On Sun, Nov 30, 2025 at 09:15:39PM +0000, Swaraj Gaikwad wrote: > Hi Mike, > > Thanks for the feedback. > > This patch was sent as an RFC because I wanted to confirm whether the > overall approach is acceptable before preparing a fully tested version. > I will send a properly tested patch once I get confirmation that this > direction makes sense. I didn't look into the details, but I think what you propose won't work. The first kernel allocates KHO scratch after parsing reserve_mem and the second kernel allocates everything from KHO scratch at the time early_params are parsed. > I’m reviewing how reserve_mem= paths are exercised so I can build an > appropriate test setup. Any guidance on recommended testing for this > area is appreciated. In general to test changes to memblock and other early code I use qemu and some scripts around it. > Thanks, > Swaraj -- Sincerely yours, Mike.