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* dax/kmem: allow kmem to add memory with memmap_on_memoryVishal Verma2023-12-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Large amounts of memory managed by the kmem driver may come in via CXL, and it is often desirable to have the memmap for this memory on the new memory itself. Enroll kmem-managed memory for memmap_on_memory semantics if the dax region originates via CXL. For non-CXL dax regions, retain the existing default behavior of hot adding without memmap_on_memory semantics. Link: https://lkml.kernel.org/r/20231107-vv-kmem_memmap-v10-3-1253ec050ed0@intel.com Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Tested-by: Li Zhijian <lizhijian@fujitsu.com> [cxl.kmem and nvdimm.kmem] Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Fan Ni <fan.ni@samsung.com> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* dax: Cleanup extra dax_region referencesDan Williams2023-06-231-7/+1
| | | | | | | | | | | | | Now that free_dev_dax_id() internally manages the references it needs the extra references taken by the dax_region drivers are not needed. Reported-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Link: https://lore.kernel.org/r/168577285161.1672036.8111253437794419696.stgit@dwillia2-xfh.jf.intel.com Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fan Ni <fan.ni@samsung.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
* cxl/dax: Create dax devices for CXL RAM regionsDan Williams2023-02-101-0/+53
While platform firmware takes some responsibility for mapping the RAM capacity of CXL devices present at boot, the OS is responsible for mapping the remainder and hot-added devices. Platform firmware is also responsible for identifying the platform general purpose memory pool, typically DDR attached DRAM, and arranging for the remainder to be 'Soft Reserved'. That reservation allows the CXL subsystem to route the memory to core-mm via memory-hotplug (dax_kmem), or leave it for dedicated access (device-dax). The new 'struct cxl_dax_region' object allows for a CXL memory resource (region) to be published, but also allow for udev and module policy to act on that event. It also prevents cxl_core.ko from having a module loading dependency on any drivers/dax/ modules. Tested-by: Fan Ni <fan.ni@samsung.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/167602003896.1924368.10335442077318970468.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>