bootmem: add debugging framework

Introduce the bootmem_debug kernel parameter that enables very verbose
diagnostics regarding all range operations of bootmem as well as the
initialization and release of nodes.

[akpm@linux-foundation.org: fix printk warnings]
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 44 insertions, 7 deletions

diff --git a/mm/bootmem.c b/mm/bootmem.c
index 105ad4cff2e1..4e085ee1d98e 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -34,6 +34,22 @@ unsigned long saved_max_pfn;
 
 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
 
+static int bootmem_debug;
+
+static int __init bootmem_debug_setup(char *buf)
+{
+        bootmem_debug = 1;
+        return 0;
+}
+early_param("bootmem_debug", bootmem_debug_setup);
+
+#define bdebug(fmt, args...) ({                         \
+        if (unlikely(bootmem_debug))                    \
+                printk(KERN_INFO                        \
+                        "bootmem::%s " fmt,             \
+                        __FUNCTION__, ## args);         \
+})
+
 /*
  * Given an initialised bdata, it returns the size of the boot bitmap
  */
@@ -104,6 +120,9 @@ static unsigned long __init init_bootmem_core(bootmem_data_t *bdata,
         mapsize = get_mapsize(bdata);
         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;
 }
 
@@ -198,6 +217,8 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
         count += i;
         bdata->node_bootmem_map = NULL;
 
+        bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
+
         return count;
 }
 
@@ -255,6 +276,10 @@ static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
         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();
@@ -360,13 +385,16 @@ 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);
 }
 
 /**
@@ -455,6 +483,10 @@ 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;
@@ -562,6 +594,11 @@ 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:
          */