bootmem: clean up free_all_bootmem_core
Johannes Weiner [Thu, 24 Jul 2008 04:28:03 +0000 (21:28 -0700)]
Rewrite the code in a more concise way using less variables.

[akpm@linux-foundation.org: fix printk warnings]
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/bootmem.c

index 9da7d40..300d126 100644 (file)
@@ -144,66 +144,59 @@ unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
 
 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 {
+       int aligned;
        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;
+       unsigned long start, end, pages, count = 0;
+
+       if (!bdata->node_bootmem_map)
+               return 0;
+
+       start = PFN_DOWN(bdata->node_boot_start);
+       end = bdata->node_low_pfn;
+
        /*
-        * 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 the start is aligned to the machines wordsize, we might
+        * be able to free pages in bulks of that order.
         */
-       if (!(pfn & (BITS_PER_LONG-1)))
-               gofast = 1;
+       aligned = !(start & (BITS_PER_LONG - 1));
+
+       bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
+               bdata - bootmem_node_data, start, end, aligned);
+
+       while (start < end) {
+               unsigned long *map, idx, vec;
 
-       for (i = 0; i < idx; ) {
-               unsigned long v = ~map[i / BITS_PER_LONG];
+               map = bdata->node_bootmem_map;
+               idx = start - PFN_DOWN(bdata->node_boot_start);
+               vec = ~map[idx / BITS_PER_LONG];
 
-               if (gofast && v == ~0UL) {
-                       int order;
+               if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
+                       int order = ilog2(BITS_PER_LONG);
 
-                       page = pfn_to_page(pfn);
+                       __free_pages_bootmem(pfn_to_page(start), order);
                        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++;
+               } else {
+                       unsigned long off = 0;
+
+                       while (vec && off < BITS_PER_LONG) {
+                               if (vec & 1) {
+                                       page = pfn_to_page(start + off);
                                        __free_pages_bootmem(page, 0);
+                                       count++;
                                }
+                               vec >>= 1;
+                               off++;
                        }
-               } else {
-                       i += BITS_PER_LONG;
                }
-               pfn += BITS_PER_LONG;
+               start += 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;
+       pages = bootmem_bootmap_pages(pages);
+       count += pages;
+       while (pages--)
+               __free_pages_bootmem(page++, 0);
 
        bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);