From patchwork Fri Feb 2 08:30:32 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 10196399 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AAAC260388 for ; Fri, 2 Feb 2018 08:39:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 977EC28D75 for ; Fri, 2 Feb 2018 08:39:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8C07228E05; Fri, 2 Feb 2018 08:39:40 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 224D028D75 for ; Fri, 2 Feb 2018 08:39:40 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id D64052238B5BF; Fri, 2 Feb 2018 00:34:01 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.88; helo=mga01.intel.com; envelope-from=dan.j.williams@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 507B1223CCF17 for ; Fri, 2 Feb 2018 00:34:00 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Feb 2018 00:39:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,447,1511856000"; d="scan'208";a="27489066" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga001.fm.intel.com with ESMTP; 02 Feb 2018 00:39:37 -0800 Subject: [PATCH] libnvdimm, namespace: make min namespace size 4K From: Dan Williams To: linux-nvdimm@lists.01.org Date: Fri, 02 Feb 2018 00:30:32 -0800 Message-ID: <151756023262.24612.12933966286242265340.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, Matthew Wilcox , Cheng-mean Liu Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP The arbitrary 4MB minimum namespace size turns out to be too large for some environments. Quoting Cheng-mean Liu: In the case of emulated NVDIMM devices in the VM environment, there are scenarios that NVDIMM device with much smaller sizes are desired, for example, we might use a single enumerated NVDIMM DAX device for representing each container layer, which in some cases could be just a few KBs size. PAGE_SIZE is the minimum where we can still support DAX of at least a single page. Cc: Matthew Wilcox Reported-by: Cheng-mean Liu Signed-off-by: Dan Williams --- include/uapi/linux/ndctl.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h index 30ef1236aafa..7e27070b9440 100644 --- a/include/uapi/linux/ndctl.h +++ b/include/uapi/linux/ndctl.h @@ -209,7 +209,7 @@ enum nd_driver_flags { }; enum { - ND_MIN_NAMESPACE_SIZE = 0x00400000, + ND_MIN_NAMESPACE_SIZE = PAGE_SIZE, }; enum ars_masks {