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 2E2B974BE1; Sun, 21 Jun 2026 10:36:23 +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=1782038185; cv=none; b=LJ+SI/rJaqyaL1Ngc4YUmJD3+1MPj0c3UI8adNoxtksHpdHquZAyiLqubBUfAnlG76Ag4xsgdeq1EM94x2QWbIcB6tMQ8ghiDfSFxPsOBN2aM2u0p9VZBNpWbONnFHl7eEEVcLYZOhKGV32T0QxwHOXid0EdI3cOBUYBaOe2ZmA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782038185; c=relaxed/simple; bh=ucrVZaFHV9P8rrX121ECboKE36C33WJ/6ZialGNhCW8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=L9SkZJJ7O57Q++NbAj1DGrUW9Jbs+MfM3umqv+aGAhvwtT8KSvf/wW9b3KBT7E4DtLOayUzL1YumpH7r0TyoExiAU/hMcr0HAH5AuEn9ErG9PscpZtCLdvHspuuQvRrztRv7pSC02OqRklpGFDF1ie2QOk0qypUch8AgGcrf4F8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bVtQJTae; 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="bVtQJTae" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3726C1F000E9; Sun, 21 Jun 2026 10:36:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782038183; bh=u7n88puASKdRn7LSLUIyKwIUjfNUuhlCupcWE32IiKc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bVtQJTaeCkbJtYPLyIXvXF62RPr79fPksVMk14M0zYNX96o6mnHvZFPA0hibhxeHo eEysclkiI4gdSzS6seo2lZ1GnN0cHxD0OLsUdJs+8fu5GWUOojKTc7iVwSQNWxCLkz NeJujBZLVSZmSKqPiolja65PdQe2IWZ9KbYqagJW6TagyYy5DsGI/Dfcn4WqhlCDBK NdACIAkSoyfexQTpPgAhSe9jb0ppgaxsnx0VTxOTB9EkT7naGOqv87ArIiEGUexrqE J+MmMWHcvyWBIENEIWGKWU6/aNbV03JUxv6U5v3cXrfQpAfileqR5zL3eFY2k3lm9C Ap825Q6Z+dW5w== Date: Sun, 21 Jun 2026 13:36:13 +0300 From: Mike Rapoport To: Shyam Saini Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tgopinath@linux.microsoft.com, bboscaccy@linux.microsoft.com, kees@kernel.org, tony.luck@intel.com, gpiccoli@igalia.com, bp@alien8.de, rdunlap@infradead.org, peterz@infradead.org, feng.tang@linux.alibaba.com, dapeng1.mi@linux.intel.com, elver@google.com, enelsonmoore@gmail.com, kuba@kernel.org, lirongqing@baidu.com, ebiggers@kernel.org Subject: Re: [RFC v2 PATCH] reserve_mem: add support for static memory Message-ID: References: <20260619062331.348789-1-shyamsaini@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-doc@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: <20260619062331.348789-1-shyamsaini@linux.microsoft.com> On Thu, Jun 18, 2026 at 11:23:31PM -0700, Shyam Saini wrote: > reserve_mem relies on dynamic memory allocation, this limits the > usecase where memory is required to be preserved across the boots. > Eg: ramoops memory reservation on ACPI platforms > > So add support to pass a pre-determined static address and reserve > memory at a specified location. This enables use case like ramoops > on ACPI platforms to reliably access ramoops region with previous > boot logs. > > Also skip the parsing of when static address is passed. > > Example syntax for static address > reserve_mem=4M@0x1E0000000:oops reserve_mem is best effort by design because such hacks as well as memmap= cannot guarantee this memory is actually free. If you want to preserve ramoops reliably, use KHO with reserve_mem. The first kernel will allocate memory, this memory will be preserved by KHO and could be picked up by the second kernel. > Signed-off-by: Shyam Saini > --- > v1: https://lore.kernel.org/lkml/0eaf3be2-5121-48b7-aeed-196405c0a480@infradead.org/ > v2: Fix code logic and incorporate Randy's suggestion > --- > .../admin-guide/kernel-parameters.txt | 15 ++++++ > mm/memblock.c | 47 +++++++++++++------ > 2 files changed, 47 insertions(+), 15 deletions(-) -- Sincerely yours, Mike.