From: Mel Gorman Date: Thu, 24 Jul 2008 04:26:49 +0000 (-0700) Subject: mm: add a basic debugging framework for memory initialisation X-Git-Tag: v2.6.27-rc1~841 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6b74ab97bc12ce74acec900f1d89a4aee2e4d70d;p=linux-2.6 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 Cc: Christoph Lameter Cc: Andy Whitcroft Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 47e7d8794f..5e20ccb5a7 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 882c510489..e1d4764435 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 18c143b3c4..4bbc8f094f 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 0034e947e4..a7ee052532 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 0000000000..c01d8dfec8 --- /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 + * + */ +#include +#include + +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 79ac4afc90..0908352ba7 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++) {