memblock: Factor the lowest level alloc function

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/mm/memblock.c b/mm/memblock.c
index 13807f280adac02555c65ef32c1d372b8621ae26..e264e8c7089295f71651382e28674ce94f7fae03 100644 (file)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -294,8 +294,8 @@ static u64 memblock_align_up(u64 addr, u64 size)
        return (addr + (size - 1)) & ~(size - 1);
 }
 
-static u64 __init memblock_alloc_nid_unreserved(u64 start, u64 end,
-                                          u64 size, u64 align)
+static u64 __init memblock_alloc_region(u64 start, u64 end,
+                                  u64 size, u64 align)
 {
        u64 base, res_base;
        long j;
@@ -318,6 +318,13 @@ static u64 __init memblock_alloc_nid_unreserved(u64 start, u64 end,
        return ~(u64)0;
 }
 
+u64 __weak __init memblock_nid_range(u64 start, u64 end, int *nid)
+{
+       *nid = 0;
+
+       return end;
+}
+
 static u64 __init memblock_alloc_nid_region(struct memblock_region *mp,
                                       u64 size, u64 align, int nid)
 {
@@ -333,8 +340,7 @@ static u64 __init memblock_alloc_nid_region(struct memblock_region *mp,
 
                this_end = memblock_nid_range(start, end, &this_nid);
                if (this_nid == nid) {
-                       u64 ret = memblock_alloc_nid_unreserved(start, this_end,
-                                                          size, align);
+                       u64 ret = memblock_alloc_region(start, this_end, size, align);
                        if (ret != ~(u64)0)
                                return ret;
                }
@@ -351,6 +357,10 @@ u64 __init memblock_alloc_nid(u64 size, u64 align, int nid)
 
        BUG_ON(0 == size);
 
+       /* We do a bottom-up search for a region with the right
+        * nid since that's easier considering how memblock_nid_range()
+        * works
+        */
        size = memblock_align_up(size, align);
 
        for (i = 0; i < mem->cnt; i++) {
@@ -383,7 +393,7 @@ u64 __init memblock_alloc_base(u64 size, u64 align, u64 max_addr)
 
 u64 __init __memblock_alloc_base(u64 size, u64 align, u64 max_addr)
 {
-       long i, j;
+       long i;
        u64 base = 0;
        u64 res_base;
 
@@ -396,33 +406,24 @@ u64 __init __memblock_alloc_base(u64 size, u64 align, u64 max_addr)
        if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
                max_addr = MEMBLOCK_REAL_LIMIT;
 
+       /* Pump up max_addr */
+       if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
+               max_addr = ~(u64)0;
+
+       /* We do a top-down search, this tends to limit memory
+        * fragmentation by keeping early boot allocs near the
+        * top of memory
+        */
        for (i = memblock.memory.cnt - 1; i >= 0; i--) {
                u64 memblockbase = memblock.memory.regions[i].base;
                u64 memblocksize = memblock.memory.regions[i].size;
 
                if (memblocksize < size)
                        continue;
-               if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
-                       base = memblock_align_down(memblockbase + memblocksize - size, align);
-               else if (memblockbase < max_addr) {
-                       base = min(memblockbase + memblocksize, max_addr);
-                       base = memblock_align_down(base - size, align);
-               } else
-                       continue;
-
-               while (base && memblockbase <= base) {
-                       j = memblock_overlaps_region(&memblock.reserved, base, size);
-                       if (j < 0) {
-                               /* this area isn't reserved, take it */
-                               if (memblock_add_region(&memblock.reserved, base, size) < 0)
-                                       return 0;
-                               return base;
-                       }
-                       res_base = memblock.reserved.regions[j].base;
-                       if (res_base < size)
-                               break;
-                       base = memblock_align_down(res_base - size, align);
-               }
+               base = min(memblockbase + memblocksize, max_addr);
+               res_base = memblock_alloc_region(memblockbase, base, size, align);
+               if (res_base != ~(u64)0)
+                       return res_base;
        }
        return 0;
 }
@@ -528,9 +529,3 @@ int memblock_is_region_reserved(u64 base, u64 size)
        return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
 }
 
-u64 __weak memblock_nid_range(u64 start, u64 end, int *nid)
-{
-       *nid = 0;
-
-       return end;
-}