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SubjectRe: [PATCH 1/5] mm/persistent-memory: match IORES_DESC name and enum memory_type one
On Mon, Jul 3, 2017 at 2:14 PM, Jérôme Glisse <jglisse@redhat.com> wrote:
> Use consistent name between IORES_DESC and enum memory_type, rename
> MEMORY_DEVICE_PUBLIC to MEMORY_DEVICE_PERSISTENT. This is to free up
> the public name for CDM (cache coherent device memory) for which the
> term public is a better match.
>
> Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> ---
> include/linux/memremap.h | 4 ++--
> kernel/memremap.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
> index 57546a07a558..2299cc2d387d 100644
> --- a/include/linux/memremap.h
> +++ b/include/linux/memremap.h
> @@ -41,7 +41,7 @@ static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
> * Specialize ZONE_DEVICE memory into multiple types each having differents
> * usage.
> *
> - * MEMORY_DEVICE_PUBLIC:
> + * MEMORY_DEVICE_PERSISTENT:
> * Persistent device memory (pmem): struct page might be allocated in different
> * memory and architecture might want to perform special actions. It is similar
> * to regular memory, in that the CPU can access it transparently. However,
> @@ -59,7 +59,7 @@ static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
> * include/linux/hmm.h and Documentation/vm/hmm.txt.
> */
> enum memory_type {
> - MEMORY_DEVICE_PUBLIC = 0,
> + MEMORY_DEVICE_PERSISTENT = 0,
> MEMORY_DEVICE_PRIVATE,
> };
>
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index b9baa6c07918..e82456c39a6a 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -350,7 +350,7 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,
> }
> pgmap->ref = ref;
> pgmap->res = &page_map->res;
> - pgmap->type = MEMORY_DEVICE_PUBLIC;
> + pgmap->type = MEMORY_DEVICE_PERSISTENT;
> pgmap->page_fault = NULL;
> pgmap->page_free = NULL;
> pgmap->data = NULL;

I think we need a different name. There's nothing "persistent" about
the devm_memremap_pages() path. Why can't they share name, is the only
difference coherence? I'm thinking something like:

MEMORY_DEVICE_PRIVATE
MEMORY_DEVICE_COHERENT /* persistent memory and coherent devices */
MEMORY_DEVICE_IO /* "public", but not coherent */

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