mm: offset align in alloc_bootmem()

need offset alignment when node_boot_start's alignment is less than
the alignment required.

use local node_boot_start to match alignment - so don't add extra operation
in search loop.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/mm/bootmem.c b/mm/bootmem.c
index 3c012fb..0f30bc8 100644 (file)
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -206,9 +206,11 @@ void * __init
 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
              unsigned long align, unsigned long goal, unsigned long limit)
 {
-       unsigned long offset, remaining_size, areasize, preferred;
+       unsigned long areasize, preferred;
        unsigned long i, start = 0, incr, eidx, end_pfn;
        void *ret;
+       unsigned long node_boot_start;
+       void *node_bootmem_map;
 
        if (!size) {
                printk("__alloc_bootmem_core(): zero-sized request\n");
@@ -216,23 +218,29 @@ __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
        }
        BUG_ON(align & (align-1));
 
-       if (limit && bdata->node_boot_start >= limit)
-               return NULL;
-
        /* on nodes without memory - bootmem_map is NULL */
        if (!bdata->node_bootmem_map)
                return NULL;
 
+       /* bdata->node_boot_start is supposed to be (12+6)bits alignment on x86_64 ? */
+       node_boot_start = bdata->node_boot_start;
+       node_bootmem_map = bdata->node_bootmem_map;
+       if (align) {
+               node_boot_start = ALIGN(bdata->node_boot_start, align);
+               if (node_boot_start > bdata->node_boot_start)
+                       node_bootmem_map = (unsigned long *)bdata->node_bootmem_map +
+                           PFN_DOWN(node_boot_start - bdata->node_boot_start)/BITS_PER_LONG;
+       }
+
+       if (limit && node_boot_start >= limit)
+               return NULL;
+
        end_pfn = bdata->node_low_pfn;
        limit = PFN_DOWN(limit);
        if (limit && end_pfn > limit)
                end_pfn = limit;
 
-       eidx = end_pfn - PFN_DOWN(bdata->node_boot_start);
-       offset = 0;
-       if (align && (bdata->node_boot_start & (align - 1UL)) != 0)
-               offset = align - (bdata->node_boot_start & (align - 1UL));
-       offset = PFN_DOWN(offset);
+       eidx = end_pfn - PFN_DOWN(node_boot_start);
 
        /*
         * We try to allocate bootmem pages above 'goal'
@@ -240,15 +248,16 @@ __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
         */
        preferred = 0;
        if (goal && PFN_DOWN(goal) < end_pfn) {
-               if (goal > bdata->node_boot_start)
-                       preferred = goal - bdata->node_boot_start;
+               if (goal > node_boot_start)
+                       preferred = goal - node_boot_start;
 
-               if (bdata->last_success >= preferred)
+               if (bdata->last_success > node_boot_start &&
+                       bdata->last_success - node_boot_start >= preferred)
                        if (!limit || (limit && limit > bdata->last_success))
-                               preferred = bdata->last_success;
+                               preferred = bdata->last_success - node_boot_start;
        }
 
-       preferred = PFN_DOWN(ALIGN(preferred, align)) + offset;
+       preferred = PFN_DOWN(ALIGN(preferred, align));
        areasize = (size + PAGE_SIZE-1) / PAGE_SIZE;
        incr = align >> PAGE_SHIFT ? : 1;
 
@@ -256,18 +265,18 @@ restart_scan:
        for (i = preferred; i < eidx;) {
                unsigned long j;
 
-               i = find_next_zero_bit(bdata->node_bootmem_map, eidx, i);
+               i = find_next_zero_bit(node_bootmem_map, eidx, i);
                i = ALIGN(i, incr);
                if (i >= eidx)
                        break;
-               if (test_bit(i, bdata->node_bootmem_map)) {
+               if (test_bit(i, node_bootmem_map)) {
                        i += incr;
                        continue;
                }
                for (j = i + 1; j < i + areasize; ++j) {
                        if (j >= eidx)
                                goto fail_block;
-                       if (test_bit(j, bdata->node_bootmem_map))
+                       if (test_bit(j, node_bootmem_map))
                                goto fail_block;
                }
                start = i;
@@ -278,14 +287,14 @@ restart_scan:
                        i += incr;
        }
 
-       if (preferred > offset) {
-               preferred = offset;
+       if (preferred > 0) {
+               preferred = 0;
                goto restart_scan;
        }
        return NULL;
 
 found:
-       bdata->last_success = PFN_PHYS(start);
+       bdata->last_success = PFN_PHYS(start) + node_boot_start;
        BUG_ON(start >= eidx);
 
        /*
@@ -295,6 +304,7 @@ found:
         */
        if (align < PAGE_SIZE &&
            bdata->last_offset && bdata->last_pos+1 == start) {
+               unsigned long offset, remaining_size;
                offset = ALIGN(bdata->last_offset, align);
                BUG_ON(offset > PAGE_SIZE);
                remaining_size = PAGE_SIZE - offset;
@@ -303,14 +313,12 @@ found:
                        /* last_pos unchanged */
                        bdata->last_offset = offset + size;
                        ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
-                                          offset +
-                                          bdata->node_boot_start);
+                                          offset + node_boot_start);
                } else {
                        remaining_size = size - remaining_size;
                        areasize = (remaining_size + PAGE_SIZE-1) / PAGE_SIZE;
                        ret = phys_to_virt(bdata->last_pos * PAGE_SIZE +
-                                          offset +
-                                          bdata->node_boot_start);
+                                          offset + node_boot_start);
                        bdata->last_pos = start + areasize - 1;
                        bdata->last_offset = remaining_size;
                }
@@ -318,14 +326,14 @@ found:
        } else {
                bdata->last_pos = start + areasize - 1;
                bdata->last_offset = size & ~PAGE_MASK;
-               ret = phys_to_virt(start * PAGE_SIZE + bdata->node_boot_start);
+               ret = phys_to_virt(start * PAGE_SIZE + node_boot_start);
        }
 
        /*
         * Reserve the area now:
         */
        for (i = start; i < start + areasize; i++)
-               if (unlikely(test_and_set_bit(i, bdata->node_bootmem_map)))
+               if (unlikely(test_and_set_bit(i, node_bootmem_map)))
                        BUG();
        memset(ret, 0, size);
        return ret;