]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - mm/bootmem.c
bootmem: revisit bitmap size calculations
[linux-2.6-omap-h63xx.git] / mm / bootmem.c
index e8fb927392b9ac02b4ad16878847551d103a1b43..484849bfc8c43032cbd8641519f3e6d10dae6876 100644 (file)
@@ -1,12 +1,12 @@
 /*
- *  linux/mm/bootmem.c
+ *  bootmem - A boot-time physical memory allocator and configurator
  *
  *  Copyright (C) 1999 Ingo Molnar
- *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
+ *                1999 Kanoj Sarcar, SGI
+ *                2008 Johannes Weiner
  *
- *  simple boot-time physical memory area allocator and
- *  free memory collector. It's used to deal with reserved
- *  system memory and memory holes as well.
+ * Access to this subsystem has to be serialized externally (which is true
+ * for the boot process anyway).
  */
 #include <linux/init.h>
 #include <linux/pfn.h>
 
 #include "internal.h"
 
-/*
- * Access to this subsystem has to be serialized externally. (this is
- * true for the boot process anyway)
- */
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;
@@ -36,16 +32,40 @@ static LIST_HEAD(bdata_list);
 unsigned long saved_max_pfn;
 #endif
 
-/* return the number of _pages_ that will be allocated for the boot bitmap */
-unsigned long __init bootmem_bootmap_pages(unsigned long pages)
+bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
+
+static int bootmem_debug;
+
+static int __init bootmem_debug_setup(char *buf)
 {
-       unsigned long mapsize;
+       bootmem_debug = 1;
+       return 0;
+}
+early_param("bootmem_debug", bootmem_debug_setup);
 
-       mapsize = (pages+7)/8;
-       mapsize = (mapsize + ~PAGE_MASK) & PAGE_MASK;
-       mapsize >>= PAGE_SHIFT;
+#define bdebug(fmt, args...) ({                                \
+       if (unlikely(bootmem_debug))                    \
+               printk(KERN_INFO                        \
+                       "bootmem::%s " fmt,             \
+                       __FUNCTION__, ## args);         \
+})
 
-       return mapsize;
+static unsigned long __init bootmap_bytes(unsigned long pages)
+{
+       unsigned long bytes = (pages + 7) / 8;
+
+       return ALIGN(bytes, sizeof(long));
+}
+
+/**
+ * bootmem_bootmap_pages - calculate bitmap size in pages
+ * @pages: number of pages the bitmap has to represent
+ */
+unsigned long __init bootmem_bootmap_pages(unsigned long pages)
+{
+       unsigned long bytes = bootmap_bytes(pages);
+
+       return PAGE_ALIGN(bytes) >> PAGE_SHIFT;
 }
 
 /*
@@ -69,28 +89,15 @@ static void __init link_bootmem(bootmem_data_t *bdata)
        list_add_tail(&bdata->list, &bdata_list);
 }
 
-/*
- * Given an initialised bdata, it returns the size of the boot bitmap
- */
-static unsigned long __init get_mapsize(bootmem_data_t *bdata)
-{
-       unsigned long mapsize;
-       unsigned long start = PFN_DOWN(bdata->node_boot_start);
-       unsigned long end = bdata->node_low_pfn;
-
-       mapsize = ((end - start) + 7) / 8;
-       return ALIGN(mapsize, sizeof(long));
-}
-
 /*
  * Called once to set up the allocator itself.
  */
-static unsigned long __init init_bootmem_core(pg_data_t *pgdat,
+static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
        unsigned long mapstart, unsigned long start, unsigned long end)
 {
-       bootmem_data_t *bdata = pgdat->bdata;
        unsigned long mapsize;
 
+       mminit_validate_memmodel_limits(&start, &end);
        bdata->node_bootmem_map = phys_to_virt(PFN_PHYS(mapstart));
        bdata->node_boot_start = PFN_PHYS(start);
        bdata->node_low_pfn = end;
@@ -100,12 +107,209 @@ static unsigned long __init init_bootmem_core(pg_data_t *pgdat,
         * Initially all pages are reserved - setup_arch() has to
         * register free RAM areas explicitly.
         */
-       mapsize = get_mapsize(bdata);
+       mapsize = bootmap_bytes(end - start);
        memset(bdata->node_bootmem_map, 0xff, mapsize);
 
+       bdebug("nid=%td start=%lx map=%lx end=%lx mapsize=%lx\n",
+               bdata - bootmem_node_data, start, mapstart, end, mapsize);
+
        return mapsize;
 }
 
+/**
+ * init_bootmem_node - register a node as boot memory
+ * @pgdat: node to register
+ * @freepfn: pfn where the bitmap for this node is to be placed
+ * @startpfn: first pfn on the node
+ * @endpfn: first pfn after the node
+ *
+ * Returns the number of bytes needed to hold the bitmap for this node.
+ */
+unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
+                               unsigned long startpfn, unsigned long endpfn)
+{
+       return init_bootmem_core(pgdat->bdata, freepfn, startpfn, endpfn);
+}
+
+/**
+ * init_bootmem - register boot memory
+ * @start: pfn where the bitmap is to be placed
+ * @pages: number of available physical pages
+ *
+ * Returns the number of bytes needed to hold the bitmap.
+ */
+unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
+{
+       max_low_pfn = pages;
+       min_low_pfn = start;
+       return init_bootmem_core(NODE_DATA(0)->bdata, start, 0, pages);
+}
+
+static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
+{
+       struct page *page;
+       unsigned long pfn;
+       unsigned long i, count;
+       unsigned long idx, pages;
+       unsigned long *map;
+       int gofast = 0;
+
+       BUG_ON(!bdata->node_bootmem_map);
+
+       count = 0;
+       /* first extant page of the node */
+       pfn = PFN_DOWN(bdata->node_boot_start);
+       idx = bdata->node_low_pfn - pfn;
+       map = bdata->node_bootmem_map;
+       /*
+        * Check if we are aligned to BITS_PER_LONG pages.  If so, we might
+        * be able to free page orders of that size at once.
+        */
+       if (!(pfn & (BITS_PER_LONG-1)))
+               gofast = 1;
+
+       for (i = 0; i < idx; ) {
+               unsigned long v = ~map[i / BITS_PER_LONG];
+
+               if (gofast && v == ~0UL) {
+                       int order;
+
+                       page = pfn_to_page(pfn);
+                       count += BITS_PER_LONG;
+                       order = ffs(BITS_PER_LONG) - 1;
+                       __free_pages_bootmem(page, order);
+                       i += BITS_PER_LONG;
+                       page += BITS_PER_LONG;
+               } else if (v) {
+                       unsigned long m;
+
+                       page = pfn_to_page(pfn);
+                       for (m = 1; m && i < idx; m<<=1, page++, i++) {
+                               if (v & m) {
+                                       count++;
+                                       __free_pages_bootmem(page, 0);
+                               }
+                       }
+               } else {
+                       i += BITS_PER_LONG;
+               }
+               pfn += BITS_PER_LONG;
+       }
+
+       /*
+        * Now free the allocator bitmap itself, it's not
+        * needed anymore:
+        */
+       page = virt_to_page(bdata->node_bootmem_map);
+       pages = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+       idx = bootmem_bootmap_pages(pages);
+       for (i = 0; i < idx; i++, page++)
+               __free_pages_bootmem(page, 0);
+       count += i;
+       bdata->node_bootmem_map = NULL;
+
+       bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
+
+       return count;
+}
+
+/**
+ * free_all_bootmem_node - release a node's free pages to the buddy allocator
+ * @pgdat: node to be released
+ *
+ * Returns the number of pages actually released.
+ */
+unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
+{
+       register_page_bootmem_info_node(pgdat);
+       return free_all_bootmem_core(pgdat->bdata);
+}
+
+/**
+ * free_all_bootmem - release free pages to the buddy allocator
+ *
+ * Returns the number of pages actually released.
+ */
+unsigned long __init free_all_bootmem(void)
+{
+       return free_all_bootmem_core(NODE_DATA(0)->bdata);
+}
+
+static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
+                                    unsigned long size)
+{
+       unsigned long sidx, eidx;
+       unsigned long i;
+
+       BUG_ON(!size);
+
+       /* out range */
+       if (addr + size < bdata->node_boot_start ||
+               PFN_DOWN(addr) > bdata->node_low_pfn)
+               return;
+       /*
+        * round down end of usable mem, partially free pages are
+        * considered reserved.
+        */
+
+       if (addr >= bdata->node_boot_start && addr < bdata->last_success)
+               bdata->last_success = addr;
+
+       /*
+        * Round up to index to the range.
+        */
+       if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
+               sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
+       else
+               sidx = 0;
+
+       eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
+       if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
+               eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+
+       bdebug("nid=%td start=%lx end=%lx\n", bdata - bootmem_node_data,
+               sidx + PFN_DOWN(bdata->node_boot_start),
+               eidx + PFN_DOWN(bdata->node_boot_start));
+
+       for (i = sidx; i < eidx; i++) {
+               if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
+                       BUG();
+       }
+}
+
+/**
+ * free_bootmem_node - mark a page range as usable
+ * @pgdat: node the range resides on
+ * @physaddr: starting address of the range
+ * @size: size of the range in bytes
+ *
+ * Partial pages will be considered reserved and left as they are.
+ *
+ * Only physical pages that actually reside on @pgdat are marked.
+ */
+void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
+                             unsigned long size)
+{
+       free_bootmem_core(pgdat->bdata, physaddr, size);
+}
+
+/**
+ * free_bootmem - mark a page range as usable
+ * @addr: starting address of the range
+ * @size: size of the range in bytes
+ *
+ * Partial pages will be considered reserved and left as they are.
+ *
+ * All physical pages within the range are marked, no matter what
+ * node they reside on.
+ */
+void __init free_bootmem(unsigned long addr, unsigned long size)
+{
+       bootmem_data_t *bdata;
+       list_for_each_entry(bdata, &bdata_list, list)
+               free_bootmem_core(bdata, addr, size);
+}
+
 /*
  * Marks a particular physical memory range as unallocatable. Usable RAM
  * might be used for boot-time allocations - or it might get added
@@ -172,52 +376,70 @@ static void __init reserve_bootmem_core(bootmem_data_t *bdata,
        if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
                eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
 
-       for (i = sidx; i < eidx; i++) {
-               if (test_and_set_bit(i, bdata->node_bootmem_map)) {
-#ifdef CONFIG_DEBUG_BOOTMEM
-                       printk("hm, page %08lx reserved twice.\n", i*PAGE_SIZE);
-#endif
-               }
-       }
+       bdebug("nid=%td start=%lx end=%lx flags=%x\n",
+               bdata - bootmem_node_data,
+               sidx + PFN_DOWN(bdata->node_boot_start),
+               eidx + PFN_DOWN(bdata->node_boot_start),
+               flags);
+
+       for (i = sidx; i < eidx; i++)
+               if (test_and_set_bit(i, bdata->node_bootmem_map))
+                       bdebug("hm, page %lx reserved twice.\n",
+                               PFN_DOWN(bdata->node_boot_start) + i);
 }
 
-static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
-                                    unsigned long size)
+/**
+ * reserve_bootmem_node - mark a page range as reserved
+ * @pgdat: node the range resides on
+ * @physaddr: starting address of the range
+ * @size: size of the range in bytes
+ * @flags: reservation flags (see linux/bootmem.h)
+ *
+ * Partial pages will be reserved.
+ *
+ * Only physical pages that actually reside on @pgdat are marked.
+ */
+int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
+                                unsigned long size, int flags)
 {
-       unsigned long sidx, eidx;
-       unsigned long i;
-
-       BUG_ON(!size);
-
-       /* out range */
-       if (addr + size < bdata->node_boot_start ||
-               PFN_DOWN(addr) > bdata->node_low_pfn)
-               return;
-       /*
-        * round down end of usable mem, partially free pages are
-        * considered reserved.
-        */
-
-       if (addr >= bdata->node_boot_start && addr < bdata->last_success)
-               bdata->last_success = addr;
+       int ret;
 
-       /*
-        * Round up to index to the range.
-        */
-       if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
-               sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
-       else
-               sidx = 0;
+       ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
+       if (ret < 0)
+               return -ENOMEM;
+       reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
+       return 0;
+}
 
-       eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
-       if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
-               eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
+/**
+ * reserve_bootmem - mark a page range as usable
+ * @addr: starting address of the range
+ * @size: size of the range in bytes
+ * @flags: reservation flags (see linux/bootmem.h)
+ *
+ * Partial pages will be reserved.
+ *
+ * All physical pages within the range are marked, no matter what
+ * node they reside on.
+ */
+int __init reserve_bootmem(unsigned long addr, unsigned long size,
+                           int flags)
+{
+       bootmem_data_t *bdata;
+       int ret;
 
-       for (i = sidx; i < eidx; i++) {
-               if (unlikely(!test_and_clear_bit(i, bdata->node_bootmem_map)))
-                       BUG();
+       list_for_each_entry(bdata, &bdata_list, list) {
+               ret = can_reserve_bootmem_core(bdata, addr, size, flags);
+               if (ret < 0)
+                       return ret;
        }
+       list_for_each_entry(bdata, &bdata_list, list)
+               reserve_bootmem_core(bdata, addr, size, flags);
+
+       return 0;
 }
+#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
 
 /*
  * We 'merge' subsequent allocations to save space. We might 'lose'
@@ -232,9 +454,9 @@ static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
  *
  * NOTE:  This function is _not_ reentrant.
  */
-void * __init
-__alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
-             unsigned long align, unsigned long goal, unsigned long limit)
+static void * __init
+alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
+               unsigned long align, unsigned long goal, unsigned long limit)
 {
        unsigned long areasize, preferred;
        unsigned long i, start = 0, incr, eidx, end_pfn;
@@ -243,7 +465,7 @@ __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
        void *node_bootmem_map;
 
        if (!size) {
-               printk("__alloc_bootmem_core(): zero-sized request\n");
+               printk("alloc_bootmem_core(): zero-sized request\n");
                BUG();
        }
        BUG_ON(align & (align-1));
@@ -252,6 +474,10 @@ __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size,
        if (!bdata->node_bootmem_map)
                return NULL;
 
+       bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
+               bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
+               align, goal, limit);
+
        /* 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;
@@ -359,6 +585,11 @@ found:
                ret = phys_to_virt(start * PAGE_SIZE + node_boot_start);
        }
 
+       bdebug("nid=%td start=%lx end=%lx\n",
+               bdata - bootmem_node_data,
+               start + PFN_DOWN(bdata->node_boot_start),
+               start + areasize + PFN_DOWN(bdata->node_boot_start));
+
        /*
         * Reserve the area now:
         */
@@ -369,140 +600,19 @@ found:
        return ret;
 }
 
-static unsigned long __init free_all_bootmem_core(pg_data_t *pgdat)
-{
-       struct page *page;
-       unsigned long pfn;
-       bootmem_data_t *bdata = pgdat->bdata;
-       unsigned long i, count, total = 0;
-       unsigned long idx;
-       unsigned long *map; 
-       int gofast = 0;
-
-       BUG_ON(!bdata->node_bootmem_map);
-
-       count = 0;
-       /* first extant page of the node */
-       pfn = PFN_DOWN(bdata->node_boot_start);
-       idx = bdata->node_low_pfn - pfn;
-       map = bdata->node_bootmem_map;
-       /* Check physaddr is O(LOG2(BITS_PER_LONG)) page aligned */
-       if (bdata->node_boot_start == 0 ||
-           ffs(bdata->node_boot_start) - PAGE_SHIFT > ffs(BITS_PER_LONG))
-               gofast = 1;
-       for (i = 0; i < idx; ) {
-               unsigned long v = ~map[i / BITS_PER_LONG];
-
-               if (gofast && v == ~0UL) {
-                       int order;
-
-                       page = pfn_to_page(pfn);
-                       count += BITS_PER_LONG;
-                       order = ffs(BITS_PER_LONG) - 1;
-                       __free_pages_bootmem(page, order);
-                       i += BITS_PER_LONG;
-                       page += BITS_PER_LONG;
-               } else if (v) {
-                       unsigned long m;
-
-                       page = pfn_to_page(pfn);
-                       for (m = 1; m && i < idx; m<<=1, page++, i++) {
-                               if (v & m) {
-                                       count++;
-                                       __free_pages_bootmem(page, 0);
-                               }
-                       }
-               } else {
-                       i += BITS_PER_LONG;
-               }
-               pfn += BITS_PER_LONG;
-       }
-       total += count;
-
-       /*
-        * Now free the allocator bitmap itself, it's not
-        * needed anymore:
-        */
-       page = virt_to_page(bdata->node_bootmem_map);
-       count = 0;
-       idx = (get_mapsize(bdata) + PAGE_SIZE-1) >> PAGE_SHIFT;
-       for (i = 0; i < idx; i++, page++) {
-               __free_pages_bootmem(page, 0);
-               count++;
-       }
-       total += count;
-       bdata->node_bootmem_map = NULL;
-
-       return total;
-}
-
-unsigned long __init init_bootmem_node(pg_data_t *pgdat, unsigned long freepfn,
-                               unsigned long startpfn, unsigned long endpfn)
-{
-       return init_bootmem_core(pgdat, freepfn, startpfn, endpfn);
-}
-
-void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
-                                unsigned long size, int flags)
-{
-       int ret;
-
-       ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
-       if (ret < 0)
-               return;
-       reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
-}
-
-void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
-                             unsigned long size)
-{
-       free_bootmem_core(pgdat->bdata, physaddr, size);
-}
-
-unsigned long __init free_all_bootmem_node(pg_data_t *pgdat)
-{
-       register_page_bootmem_info_node(pgdat);
-       return free_all_bootmem_core(pgdat);
-}
-
-unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
-{
-       max_low_pfn = pages;
-       min_low_pfn = start;
-       return init_bootmem_core(NODE_DATA(0), start, 0, pages);
-}
-
-#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
-int __init reserve_bootmem(unsigned long addr, unsigned long size,
-                           int flags)
-{
-       bootmem_data_t *bdata;
-       int ret;
-
-       list_for_each_entry(bdata, &bdata_list, list) {
-               ret = can_reserve_bootmem_core(bdata, addr, size, flags);
-               if (ret < 0)
-                       return ret;
-       }
-       list_for_each_entry(bdata, &bdata_list, list)
-               reserve_bootmem_core(bdata, addr, size, flags);
-
-       return 0;
-}
-#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
-
-void __init free_bootmem(unsigned long addr, unsigned long size)
-{
-       bootmem_data_t *bdata;
-       list_for_each_entry(bdata, &bdata_list, list)
-               free_bootmem_core(bdata, addr, size);
-}
-
-unsigned long __init free_all_bootmem(void)
-{
-       return free_all_bootmem_core(NODE_DATA(0));
-}
-
+/**
+ * __alloc_bootmem_nopanic - allocate boot memory without panicking
+ * @size: size of the request in bytes
+ * @align: alignment of the region
+ * @goal: preferred starting address of the region
+ *
+ * The goal is dropped if it can not be satisfied and the allocation will
+ * fall back to memory below @goal.
+ *
+ * Allocation may happen on any node in the system.
+ *
+ * Returns NULL on failure.
+ */
 void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
                                      unsigned long goal)
 {
@@ -510,13 +620,26 @@ void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
        void *ptr;
 
        list_for_each_entry(bdata, &bdata_list, list) {
-               ptr = __alloc_bootmem_core(bdata, size, align, goal, 0);
+               ptr = alloc_bootmem_core(bdata, size, align, goal, 0);
                if (ptr)
                        return ptr;
        }
        return NULL;
 }
 
+/**
+ * __alloc_bootmem - allocate boot memory
+ * @size: size of the request in bytes
+ * @align: alignment of the region
+ * @goal: preferred starting address of the region
+ *
+ * The goal is dropped if it can not be satisfied and the allocation will
+ * fall back to memory below @goal.
+ *
+ * Allocation may happen on any node in the system.
+ *
+ * The function panics if the request can not be satisfied.
+ */
 void * __init __alloc_bootmem(unsigned long size, unsigned long align,
                              unsigned long goal)
 {
@@ -532,13 +655,27 @@ void * __init __alloc_bootmem(unsigned long size, unsigned long align,
        return NULL;
 }
 
-
+/**
+ * __alloc_bootmem_node - allocate boot memory from a specific node
+ * @pgdat: node to allocate from
+ * @size: size of the request in bytes
+ * @align: alignment of the region
+ * @goal: preferred starting address of the region
+ *
+ * The goal is dropped if it can not be satisfied and the allocation will
+ * fall back to memory below @goal.
+ *
+ * Allocation may fall back to any node in the system if the specified node
+ * can not hold the requested memory.
+ *
+ * The function panics if the request can not be satisfied.
+ */
 void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
                                   unsigned long align, unsigned long goal)
 {
        void *ptr;
 
-       ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
+       ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
        if (ptr)
                return ptr;
 
@@ -546,6 +683,13 @@ void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
 }
 
 #ifdef CONFIG_SPARSEMEM
+/**
+ * alloc_bootmem_section - allocate boot memory from a specific section
+ * @size: size of the request in bytes
+ * @section_nr: sparse map section to allocate from
+ *
+ * Return NULL on failure.
+ */
 void * __init alloc_bootmem_section(unsigned long size,
                                    unsigned long section_nr)
 {
@@ -557,8 +701,8 @@ void * __init alloc_bootmem_section(unsigned long size,
        goal = PFN_PHYS(pfn);
        limit = PFN_PHYS(section_nr_to_pfn(section_nr + 1)) - 1;
        pgdat = NODE_DATA(early_pfn_to_nid(pfn));
-       ptr = __alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
-                                  limit);
+       ptr = alloc_bootmem_core(pgdat->bdata, size, SMP_CACHE_BYTES, goal,
+                               limit);
 
        if (!ptr)
                return NULL;
@@ -576,10 +720,35 @@ void * __init alloc_bootmem_section(unsigned long size,
 }
 #endif
 
+void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
+                                  unsigned long align, unsigned long goal)
+{
+       void *ptr;
+
+       ptr = alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
+       if (ptr)
+               return ptr;
+
+       return __alloc_bootmem_nopanic(size, align, goal);
+}
+
 #ifndef ARCH_LOW_ADDRESS_LIMIT
 #define ARCH_LOW_ADDRESS_LIMIT 0xffffffffUL
 #endif
 
+/**
+ * __alloc_bootmem_low - allocate low boot memory
+ * @size: size of the request in bytes
+ * @align: alignment of the region
+ * @goal: preferred starting address of the region
+ *
+ * The goal is dropped if it can not be satisfied and the allocation will
+ * fall back to memory below @goal.
+ *
+ * Allocation may happen on any node in the system.
+ *
+ * The function panics if the request can not be satisfied.
+ */
 void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
                                  unsigned long goal)
 {
@@ -587,8 +756,8 @@ void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
        void *ptr;
 
        list_for_each_entry(bdata, &bdata_list, list) {
-               ptr = __alloc_bootmem_core(bdata, size, align, goal,
-                                               ARCH_LOW_ADDRESS_LIMIT);
+               ptr = alloc_bootmem_core(bdata, size, align, goal,
+                                       ARCH_LOW_ADDRESS_LIMIT);
                if (ptr)
                        return ptr;
        }
@@ -601,9 +770,24 @@ void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
        return NULL;
 }
 
+/**
+ * __alloc_bootmem_low_node - allocate low boot memory from a specific node
+ * @pgdat: node to allocate from
+ * @size: size of the request in bytes
+ * @align: alignment of the region
+ * @goal: preferred starting address of the region
+ *
+ * The goal is dropped if it can not be satisfied and the allocation will
+ * fall back to memory below @goal.
+ *
+ * Allocation may fall back to any node in the system if the specified node
+ * can not hold the requested memory.
+ *
+ * The function panics if the request can not be satisfied.
+ */
 void * __init __alloc_bootmem_low_node(pg_data_t *pgdat, unsigned long size,
                                       unsigned long align, unsigned long goal)
 {
-       return __alloc_bootmem_core(pgdat->bdata, size, align, goal,
-                                   ARCH_LOW_ADDRESS_LIMIT);
+       return alloc_bootmem_core(pgdat->bdata, size, align, goal,
+                               ARCH_LOW_ADDRESS_LIMIT);
 }