mm: add a basic debugging framework for memory initialisation
Boot initialisation is very complex, with significant numbers of
architecture-specific routines, hooks and code ordering. While significant
amounts of the initialisation is architecture-independent, it trusts the data
received from the architecture layer. This is a mistake, and has resulted in
a number of difficult-to-diagnose bugs.
This patchset adds some validation and tracing to memory initialisation. It
also introduces a few basic defensive measures. The validation code can be
explicitly disabled for embedded systems.
This patch:
Add additional debugging and verification code for memory initialisation.
Once enabled, the verification checks are always run and when required
additional debugging information may be outputted via a mminit_loglevel=
command-line parameter.
The verification code is placed in a new file mm/mm_init.c. Ideally other mm
initialisation code will be moved here over time.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/Makefile b/mm/Makefile
index 18c143b..4bbc8f0 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -26,6 +26,7 @@
obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_SLAB) += slab.o
+obj-$(CONFIG_DEBUG_MEMORY_INIT) += mm_init.o
obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
diff --git a/mm/internal.h b/mm/internal.h
index 0034e94..a7ee052 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -59,4 +59,31 @@
#define __paginginit __init
#endif
+/* Memory initialisation debug and verification */
+enum mminit_level {
+ MMINIT_WARNING,
+ MMINIT_VERIFY,
+ MMINIT_TRACE
+};
+
+#ifdef CONFIG_DEBUG_MEMORY_INIT
+
+extern int mminit_loglevel;
+
+#define mminit_dprintk(level, prefix, fmt, arg...) \
+do { \
+ if (level < mminit_loglevel) { \
+ printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
+ printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
+ } \
+} while (0)
+
+#else
+
+static inline void mminit_dprintk(enum mminit_level level,
+ const char *prefix, const char *fmt, ...)
+{
+}
+
+#endif /* CONFIG_DEBUG_MEMORY_INIT */
#endif
diff --git a/mm/mm_init.c b/mm/mm_init.c
new file mode 100644
index 0000000..c01d8df
--- /dev/null
+++ b/mm/mm_init.c
@@ -0,0 +1,18 @@
+/*
+ * mm_init.c - Memory initialisation verification and debugging
+ *
+ * Copyright 2008 IBM Corporation, 2008
+ * Author Mel Gorman <mel@csn.ul.ie>
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+int __meminitdata mminit_loglevel;
+
+static __init int set_mminit_loglevel(char *str)
+{
+ get_option(&str, &mminit_loglevel);
+ return 0;
+}
+early_param("mminit_loglevel", set_mminit_loglevel);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 79ac4af..0908352 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2975,7 +2975,8 @@
void __init push_node_boundaries(unsigned int nid,
unsigned long start_pfn, unsigned long end_pfn)
{
- printk(KERN_DEBUG "Entering push_node_boundaries(%u, %lu, %lu)\n",
+ mminit_dprintk(MMINIT_TRACE, "zoneboundary",
+ "Entering push_node_boundaries(%u, %lu, %lu)\n",
nid, start_pfn, end_pfn);
/* Initialise the boundary for this node if necessary */
@@ -2993,7 +2994,8 @@
static void __meminit account_node_boundary(unsigned int nid,
unsigned long *start_pfn, unsigned long *end_pfn)
{
- printk(KERN_DEBUG "Entering account_node_boundary(%u, %lu, %lu)\n",
+ mminit_dprintk(MMINIT_TRACE, "zoneboundary",
+ "Entering account_node_boundary(%u, %lu, %lu)\n",
nid, *start_pfn, *end_pfn);
/* Return if boundary information has not been provided */
@@ -3368,8 +3370,8 @@
PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
if (realsize >= memmap_pages) {
realsize -= memmap_pages;
- printk(KERN_DEBUG
- " %s zone: %lu pages used for memmap\n",
+ mminit_dprintk(MMINIT_TRACE, "memmap_init",
+ "%s zone: %lu pages used for memmap\n",
zone_names[j], memmap_pages);
} else
printk(KERN_WARNING
@@ -3379,7 +3381,8 @@
/* Account for reserved pages */
if (j == 0 && realsize > dma_reserve) {
realsize -= dma_reserve;
- printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
+ mminit_dprintk(MMINIT_TRACE, "memmap_init",
+ "%s zone: %lu pages reserved\n",
zone_names[0], dma_reserve);
}
@@ -3520,10 +3523,11 @@
{
int i;
- printk(KERN_DEBUG "Entering add_active_range(%d, %#lx, %#lx) "
- "%d entries of %d used\n",
- nid, start_pfn, end_pfn,
- nr_nodemap_entries, MAX_ACTIVE_REGIONS);
+ mminit_dprintk(MMINIT_TRACE, "memory_register",
+ "Entering add_active_range(%d, %#lx, %#lx) "
+ "%d entries of %d used\n",
+ nid, start_pfn, end_pfn,
+ nr_nodemap_entries, MAX_ACTIVE_REGIONS);
/* Merge with existing active regions if possible */
for (i = 0; i < nr_nodemap_entries; i++) {