Re: [PATCH v2 19/22] mm/memremap_pages: Convert to 'struct range'

From: Ralph Campbell <rcampbell@nvidia.com>
To: Dan Williams <dan.j.williams@intel.com>, <linux-nvdimm@lists.01.org>
Cc: Paul Mackerras <paulus@ozlabs.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Ben Skeggs <bskeggs@redhat.com>, David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>, Ira Weiny <ira.weiny@intel.com>,
	Jason Gunthorpe <jgg@mellanox.com>, <peterz@infradead.org>,
	<dave.hansen@linux.intel.com>, <ard.biesheuvel@linaro.org>,
	<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
	<linux-acpi@vger.kernel.org>, <hch@lst.de>,
	<joao.m.martins@oracle.com>
Subject: Re: [PATCH v2 19/22] mm/memremap_pages: Convert to 'struct range'
Date: Mon, 13 Jul 2020 09:36:16 -0700	[thread overview]
Message-ID: <52e00a67-b686-8554-8b92-a172ba9f34b6@nvidia.com> (raw)
In-Reply-To: <159457126779.754248.3575056680831729751.stgit@dwillia2-desk3.amr.corp.intel.com>

On 7/12/20 9:27 AM, Dan Williams wrote:
> The 'struct resource' in 'struct dev_pagemap' is only used for holding
> resource span information. The other fields, 'name', 'flags', 'desc',
> 'parent', 'sibling', and 'child' are all unused wasted space.
> 
> This is in preparation for introducing a multi-range extension of
> devm_memremap_pages().
> 
> The bulk of this change is unwinding all the places internal to
> libnvdimm that used 'struct resource' unnecessarily.
> 
> P2PDMA had a minor usage of the flags field, but only to report failures
> with "%pR". That is replaced with an open coded print of the range.
> 
> Cc: Paul Mackerras <paulus@ozlabs.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Jason Gunthorpe <jgg@mellanox.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>   arch/powerpc/kvm/book3s_hv_uvmem.c     |   13 +++--
>   drivers/dax/bus.c                      |   10 ++--
>   drivers/dax/bus.h                      |    2 -
>   drivers/dax/dax-private.h              |    5 --
>   drivers/dax/device.c                   |    3 -
>   drivers/dax/hmem/hmem.c                |    5 ++
>   drivers/dax/pmem/core.c                |   12 ++---
>   drivers/gpu/drm/nouveau/nouveau_dmem.c |    3 +
>   drivers/nvdimm/badrange.c              |   26 +++++------
>   drivers/nvdimm/claim.c                 |   13 +++--
>   drivers/nvdimm/nd.h                    |    3 +
>   drivers/nvdimm/pfn_devs.c              |   12 ++---
>   drivers/nvdimm/pmem.c                  |   26 ++++++-----
>   drivers/nvdimm/region.c                |   21 +++++----
>   drivers/pci/p2pdma.c                   |   11 ++---
>   include/linux/memremap.h               |    5 +-
>   include/linux/range.h                  |    6 ++
>   mm/memremap.c                          |   77 ++++++++++++++++----------------
>   tools/testing/nvdimm/test/iomap.c      |    2 -
>   19 files changed, 135 insertions(+), 120 deletions(-)

I think you are missing a call to memremap_pages() in lib/test_hmm.c
and a call to release_mem_region() that need to be converted too.
Try setting CONFIG_TEST_HMM=m.

Also, what about the call to release_mem_region() in
drivers/gpu/drm/nouveau/nouveau_dmem.c? Doesn't that need a small change too?