From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 426A46B0003 for ; Tue, 7 Aug 2018 05:11:24 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id d5-v6so5166066edq.3 for ; Tue, 07 Aug 2018 02:11:24 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id w43-v6si1167506edc.207.2018.08.07.02.11.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Aug 2018 02:11:22 -0700 (PDT) Date: Tue, 7 Aug 2018 11:11:20 +0200 From: Jan Kara Subject: Re: [PATCH V2 2/4] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Message-ID: <20180807091120.ybne44o2fy2mxcch@quack2.suse.cz> References: <7e20d862f96662e1a7736dbb747a71949933dcd4.1531241281.git.yi.z.zhang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7e20d862f96662e1a7736dbb747a71949933dcd4.1531241281.git.yi.z.zhang@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Zhang Yi Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, pbonzini@redhat.com, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com, linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com 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 > */ > enum memory_type { > MEMORY_DEVICE_PRIVATE = 1, > MEMORY_DEVICE_PUBLIC, > MEMORY_DEVICE_FS_DAX, > + MEMORY_DEVICE_DEV_DAX, > }; > > /* > -- > 2.7.4 > -- Jan Kara SUSE Labs, CR