From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f71.google.com (mail-pl0-f71.google.com [209.85.160.71]) by kanga.kvack.org (Postfix) with ESMTP id 5DE016B0003 for ; Tue, 7 Aug 2018 21:38:40 -0400 (EDT) Received: by mail-pl0-f71.google.com with SMTP id u2-v6so455029pls.7 for ; Tue, 07 Aug 2018 18:38:40 -0700 (PDT) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id 1-v6si2166776plj.411.2018.08.07.18.38.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Aug 2018 18:38:39 -0700 (PDT) Subject: Re: [PATCH V2 2/4] mm: introduce memory type MEMORY_DEVICE_DEV_DAX References: <7e20d862f96662e1a7736dbb747a71949933dcd4.1531241281.git.yi.z.zhang@linux.intel.com> <20180807091120.ybne44o2fy2mxcch@quack2.suse.cz> From: "Zhang,Yi" Message-ID: <60a42f73-1772-24eb-26f0-efd892b0487c@linux.intel.com> Date: Wed, 8 Aug 2018 17:22:42 +0800 MIME-Version: 1.0 In-Reply-To: <20180807091120.ybne44o2fy2mxcch@quack2.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan.j.williams@intel.com, hch@lst.de, yu.c.zhang@intel.com, linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com On 2018a1'08ae??07ae?JPY 17:11, Jan Kara wrote: > On Wed 11-07-18 01:01:59, Zhang Yi wrote: >> Currently, NVDIMM pages will be marked 'PageReserved'. However, unlike >> other reserved PFNs, pages on NVDIMM shall still behave like normal ones >> in many cases, i.e. when used as backend memory of KVM guest. This patch >> introduces a new memory type, MEMORY_DEVICE_DEV_DAX. And set this flag >> while dax driver hotplug the device memory. >> >> Signed-off-by: Zhang Yi >> Signed-off-by: Zhang Yu >> --- >> drivers/dax/pmem.c | 1 + >> include/linux/memremap.h | 9 +++++++++ >> 2 files changed, 10 insertions(+) >> >> diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c >> index fd49b24..fb3f363 100644 >> --- a/drivers/dax/pmem.c >> +++ b/drivers/dax/pmem.c >> @@ -111,6 +111,7 @@ static int dax_pmem_probe(struct device *dev) >> return rc; >> >> dax_pmem->pgmap.ref = &dax_pmem->ref; >> + dax_pmem->pgmap.type = MEMORY_DEVICE_DEV_DAX; >> addr = devm_memremap_pages(dev, &dax_pmem->pgmap); >> if (IS_ERR(addr)) >> return PTR_ERR(addr); >> diff --git a/include/linux/memremap.h b/include/linux/memremap.h >> index 5ebfff6..a36bce8 100644 >> --- a/include/linux/memremap.h >> +++ b/include/linux/memremap.h >> @@ -53,11 +53,20 @@ struct vmem_altmap { >> * wakeup event whenever a page is unpinned and becomes idle. This >> * wakeup is used to coordinate physical address space management (ex: >> * fs truncate/hole punch) vs pinned pages (ex: device dma). >> + * >> + * MEMORY_DEVICE_DEV_DAX: >> + * DAX driver hotplug the device memory and move it to memory zone, these >> + * pages will be marked reserved flag. However, some other kernel componet >> + * will misconceive these pages are reserved mmio (ex: we map these dev_dax >> + * or fs_dax pages to kvm for DIMM/NVDIMM backend). Together with the type >> + * MEMORY_DEVICE_FS_DAX, we can differentiate the pages on NVDIMM with the >> + * normal reserved pages. > So I believe the description should be in terms of what kind of memory is > the MEMORY_DEVICE_DEV_DAX type, not how users use this type. See comments > for other memory types... > > Honza Yes, agree, thanks for your kindly review. Jan. > >> */ >> enum memory_type { >> MEMORY_DEVICE_PRIVATE = 1, >> MEMORY_DEVICE_PUBLIC, >> MEMORY_DEVICE_FS_DAX, >> + MEMORY_DEVICE_DEV_DAX, >> }; >> >> /* >> -- >> 2.7.4 >>