mm/memblock.c: expose total reserved memory

The total reserved memory in a system is accounted but not available for
use use outside mm/memblock.c.  By exposing the total reserved memory,
systems can better calculate the size of large hashes.

Link: http://lkml.kernel.org/r/1472476010-4709-3-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 2925da23505d..5b759c9acf97 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -328,6 +328,7 @@ phys_addr_t memblock_alloc_base(phys_addr_t size, phys_addr_t align,
 phys_addr_t __memblock_alloc_base(phys_addr_t size, phys_addr_t align,
                                   phys_addr_t max_addr);
 phys_addr_t memblock_phys_mem_size(void);
+phys_addr_t memblock_reserved_size(void);
 phys_addr_t memblock_mem_size(unsigned long limit_pfn);
 phys_addr_t memblock_start_of_DRAM(void);
 phys_addr_t memblock_end_of_DRAM(void);
diff --git a/mm/memblock.c b/mm/memblock.c
index 483197ef613f..c8dfa430342b 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1438,6 +1438,11 @@ phys_addr_t __init_memblock memblock_phys_mem_size(void)
         return memblock.memory.total_size;
 }
 
+phys_addr_t __init_memblock memblock_reserved_size(void)
+{
+        return memblock.reserved.total_size;
+}
+
 phys_addr_t __init memblock_mem_size(unsigned long limit_pfn)
 {
         unsigned long pages = 0;