From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0AB1C433E5 for ; Fri, 21 Aug 2020 22:56:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 574FC207C3 for ; Fri, 21 Aug 2020 22:56:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="iI4dJvXr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 574FC207C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AA2DF8D0092; Fri, 21 Aug 2020 18:56:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A55788D004C; Fri, 21 Aug 2020 18:56:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 96B1C8D0092; Fri, 21 Aug 2020 18:56:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 841F28D004C for ; Fri, 21 Aug 2020 18:56:52 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 4D4EC180AD802 for ; Fri, 21 Aug 2020 22:56:52 +0000 (UTC) X-FDA: 77176087464.16.thing27_101432f2703d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 1F107100E6903 for ; Fri, 21 Aug 2020 22:56:52 +0000 (UTC) X-HE-Tag: thing27_101432f2703d X-Filterd-Recvd-Size: 3182 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Fri, 21 Aug 2020 22:56:51 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 452372067C; Fri, 21 Aug 2020 22:56:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598050610; bh=ZrUsTOSSrUKu+XmJ3n3QrX2IzU2U3VsMZK0kOK4GMiE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=iI4dJvXrsyw1+Tk8OEZKoXVwWx2kqLp0ly8GxASNosQKHAXDZv5hwcn5CC134bPNF caEROIqNlU8S+OxwkzchiFzFM3PRmD56ol/2Kerc6cXsp7ApDyw1xvfhmsSsve7A27 J1H7gbEkUDr4MCZZrQPSaW1dzJPF0DqbhJe8baJc= Date: Fri, 21 Aug 2020 15:56:49 -0700 From: Andrew Morton To: Dan Williams Cc: Vishal Verma , peterz@infradead.org, dave.hansen@linux.intel.com, ard.biesheuvel@linaro.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, joao.m.martins@oracle.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH v4 15/23] device-dax: Add resize support Message-Id: <20200821155649.6a9fe5eb22a013833f94427c@linux-foundation.org> In-Reply-To: <159643102625.4062302.7431838945566033852.stgit@dwillia2-desk3.amr.corp.intel.com> References: <159643094279.4062302.17779410714418721328.stgit@dwillia2-desk3.amr.corp.intel.com> <159643102625.4062302.7431838945566033852.stgit@dwillia2-desk3.amr.corp.intel.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 1F107100E6903 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 02 Aug 2020 22:03:46 -0700 Dan Williams wrote: > Make the device-dax 'size' attribute writable to allow capacity to be > split between multiple instances in a region. The intended consumers of > this capability are users that want to split a scarce memory resource > between device-dax and System-RAM access, or users that want to have > multiple security domains for a large region. > > By default the hmem instance provider allocates an entire region to the > first instance. The process of creating a new instance (assuming a > region-id of 0) is find the region and trigger the 'create' attribute > which yields an empty instance to configure. For example: > > cd /sys/bus/dax/devices > echo dax0.0 > dax0.0/driver/unbind > echo $new_size > dax0.0/size > echo 1 > $(readlink -f dax0.0)../dax_region/create > seed=$(cat $(readlink -f dax0.0)../dax_region/seed) > echo $new_size > $seed/size > echo dax0.0 > ../drivers/{device_dax,kmem}/bind > echo dax0.1 > ../drivers/{device_dax,kmem}/bind > > Instances can be destroyed by: > > echo $device > $(readlink -f $device)../dax_region/delete This userspace interface doesn't seem to be documented anywhere, so there's nothing to update for this patch :(