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 <[email protected]> >> Signed-off-by: Zhang Yu <[email protected]> >> --- >> 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 >>
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