From 6b74ab97bc12ce74acec900f1d89a4aee2e4d70d Mon Sep 17 00:00:00 2001
From: Mel Gorman <mel@csn.ul.ie>
Date: Wed, 23 Jul 2008 21:26:49 -0700
Subject: [PATCH] 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>
---
Documentation/kernel-parameters.txt | 8 ++++++++
lib/Kconfig.debug | 12 ++++++++++++
mm/Makefile | 1 +
mm/internal.h | 27 +++++++++++++++++++++++++++
mm/mm_init.c | 18 ++++++++++++++++++
mm/page_alloc.c | 22 +++++++++++++---------
6 files changed, 79 insertions(+), 9 deletions(-)
create mode 100644 mm/mm_init.c
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 47e7d8794fc6f..5e20ccb5a736e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1225,6 +1225,14 @@ and is between 256 and 4096 characters. It is defined in the file
mga= [HW,DRM]
+ mminit_loglevel=
+ [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
+ parameter allows control of the logging verbosity for
+ the additional memory initialisation checks. A value
+ of 0 disables mminit logging and a level of 4 will
+ log everything. Information is printed at KERN_DEBUG
+ so loglevel=8 may also need to be specified.
+
mousedev.tap_time=
[MOUSE] Maximum time between finger touching and
leaving touchpad surface for touch to be considered
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 882c510489930..e1d4764435ed8 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -505,6 +505,18 @@ config DEBUG_WRITECOUNT
If unsure, say N.
+config DEBUG_MEMORY_INIT
+ bool "Debug memory initialisation" if EMBEDDED
+ default !EMBEDDED
+ help
+ Enable this for additional checks during memory initialisation.
+ The sanity checks verify aspects of the VM such as the memory model
+ and other information provided by the architecture. Verbose
+ information will be printed at KERN_DEBUG loglevel depending
+ on the mminit_loglevel= command-line option.
+
+ If unsure, say Y
+
config DEBUG_LIST
bool "Debug linked list manipulation"
depends on DEBUG_KERNEL
diff --git a/mm/Makefile b/mm/Makefile
index 18c143b3c46cd..4bbc8f094ff04 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o
obj-$(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 0034e947e4bc6..a7ee052532943 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -59,4 +59,31 @@ static inline unsigned long page_order(struct page *page)
#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 0000000000000..c01d8dfec8177
--- /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 79ac4afc908cf..0908352ba727b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2975,7 +2975,8 @@ void __init sparse_memory_present_with_active_regions(int nid)
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 @@ void __init push_node_boundaries(unsigned int nid,
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 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
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 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
/* 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 @@ void __init add_active_range(unsigned int nid, unsigned long start_pfn,
{
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++) {
--
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