On 2018年08月07日 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 <yi.z.zhang@xxxxxxxxxxxxxxx>
>> Signed-off-by: Zhang Yu <yu.c.zhang@xxxxxxxxxxxxxxx>
>> ---
>> 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
>>
