From 92281dee825f6d2eb07c441437e4196a44b0861c Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 10 Aug 2015 23:07:06 -0400 Subject: arch: introduce memremap() Existing users of ioremap_cache() are mapping memory that is known in advance to not have i/o side effects. These users are forced to cast away the __iomem annotation, or otherwise neglect to fix the sparse errors thrown when dereferencing pointers to this memory. Provide memremap() as a non __iomem annotated ioremap_*() in the case when ioremap is otherwise a pointer to cacheable memory. Empirically, ioremap_() call sites are seeking memory-like semantics (e.g. speculative reads, and prefetching permitted). memremap() is a break from the ioremap implementation pattern of adding a new memremap_() for each mapping type and having silent compatibility fall backs. Instead, the implementation defines flags that are passed to the central memremap() and if a mapping type is not supported by an arch memremap returns NULL. We introduce a memremap prototype as a trivial wrapper of ioremap_cache() and ioremap_wt(). Later, once all ioremap_cache() and ioremap_wt() usage has been removed from drivers we teach archs to implement arch_memremap() with the ability to strictly enforce the mapping type. Cc: Arnd Bergmann Reviewed-by: Christoph Hellwig Signed-off-by: Dan Williams --- arch/sh/include/asm/io.h | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/sh') diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h index 728c4c571f40..6194e20fccca 100644 --- a/arch/sh/include/asm/io.h +++ b/arch/sh/include/asm/io.h @@ -342,6 +342,7 @@ ioremap_cache(phys_addr_t offset, unsigned long size) { return __ioremap_mode(offset, size, PAGE_KERNEL); } +#define ioremap_cache ioremap_cache #ifdef CONFIG_HAVE_IOREMAP_PROT static inline void __iomem * -- cgit v1.2.3 From 033fbae988fcb67e5077203512181890848b8e90 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Sun, 9 Aug 2015 15:29:06 -0400 Subject: 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 Cc: Ingo Molnar Cc: Dave Hansen Cc: Rik van Riel Cc: Mel Gorman Cc: Jerome Glisse [hch: various simplifications in the arch interface] Signed-off-by: Christoph Hellwig Signed-off-by: Dan Williams --- arch/sh/mm/init.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/sh') 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); -- cgit v1.2.3