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| author | Dan Williams <dan.j.williams@intel.com> | 2015-08-09 15:29:06 -0400 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2015-08-27 19:40:58 -0400 |
| commit | 033fbae988fcb67e5077203512181890848b8e90 (patch) | |
| tree | d0b9e418ab4f1df15435c098edf5ad687b426b3f /arch/sh | |
| parent | 012dcef3f058385268630c0003e9b7f8dcafbeb4 (diff) | |
| download | lwn-033fbae988fcb67e5077203512181890848b8e90.tar.gz lwn-033fbae988fcb67e5077203512181890848b8e90.zip | |
mm: ZONE_DEVICE for "device memory"
While pmem is usable as a block device or via DAX mappings to userspace
there are several usage scenarios that can not target pmem due to its
lack of struct page coverage. In preparation for "hot plugging" pmem
into the vmemmap add ZONE_DEVICE as a new zone to tag these pages
separately from the ones that are subject to standard page allocations.
Importantly "device memory" can be removed at will by userspace
unbinding the driver of the device.
Having a separate zone prevents allocation and otherwise marks these
pages that are distinct from typical uniform memory. Device memory has
different lifetime and performance characteristics than RAM. However,
since we have run out of ZONES_SHIFT bits this functionality currently
depends on sacrificing ZONE_DMA.
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Jerome Glisse <j.glisse@gmail.com>
[hch: various simplifications in the arch interface]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'arch/sh')
| -rw-r--r-- | arch/sh/mm/init.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c index 2790b6a64157..c1490096b863 100644 --- a/arch/sh/mm/init.c +++ b/arch/sh/mm/init.c @@ -485,7 +485,7 @@ void free_initrd_mem(unsigned long start, unsigned long end) #endif #ifdef CONFIG_MEMORY_HOTPLUG -int arch_add_memory(int nid, u64 start, u64 size) +int arch_add_memory(int nid, u64 start, u64 size, bool for_device) { pg_data_t *pgdat; unsigned long start_pfn = start >> PAGE_SHIFT; @@ -496,7 +496,8 @@ int arch_add_memory(int nid, u64 start, u64 size) /* We only have ZONE_NORMAL, so this is easy.. */ ret = __add_pages(nid, pgdat->node_zones + - zone_for_memory(nid, start, size, ZONE_NORMAL), + zone_for_memory(nid, start, size, ZONE_NORMAL, + for_device), start_pfn, nr_pages); if (unlikely(ret)) printk("%s: Failed, __add_pages() == %d\n", __func__, ret); |