Yinghai Lu wrote:
On Thu, Feb 17, 2011 at 10:51 AM, Mike Travis <travis@xxxxxxx> wrote:On larger systems, because of the numerous ACPI, Bootmem and EFI messages, the static log buffer overflows before the larger one specified by the log_buf_len param is allocated. Minimize the overflow by allocating the new log buffer as soon as possible. All arch's are covered by the "setup_log_buf" in start_kernel(). The x86 arch allocates it right after bootmem is created. v1: Added pertinent __init & __initdata specifiers. v2: updated to apply to x86-tip Signed-off-by: Mike Travis <travis@xxxxxxx> Reviewed-by: Jack Steiner <steiner@xxxxxxx> Reviewed-by: Robin Holt <holt@xxxxxxx> --- arch/x86/kernel/setup.c | 5 ++ include/linux/printk.h | 4 ++ init/main.c | 1 kernel/printk.c | 81 +++++++++++++++++++++++++++++------------------- 4 files changed, 60 insertions(+), 31 deletions(-) --- linux.orig/arch/x86/kernel/setup.c +++ linux/arch/x86/kernel/setup.c @@ -1007,6 +1007,11 @@ void __init setup_arch(char **cmdline_p) memblock_find_dma_reserve(); dma32_reserve_bootmem(); + /* + * Allocate bigger log buffer as early as possible + */ + setup_log_buf(); + #ifdef CONFIG_KVM_CLOCK kvmclock_init(); #endif --- linux.orig/include/linux/printk.h +++ linux/include/linux/printk.h @@ -1,6 +1,8 @@ #ifndef __KERNEL_PRINTK__ #define __KERNEL_PRINTK__ +#include <linux/init.h> + extern const char linux_banner[]; extern const char linux_proc_banner[]; @@ -89,6 +91,8 @@ int no_printk(const char *fmt, ...) extern asmlinkage __attribute__ ((format (printf, 1, 2))) void early_printk(const char *fmt, ...); +void __init setup_log_buf(void); + extern int printk_needs_cpu(int cpu); extern void printk_tick(void); --- linux.orig/init/main.c +++ linux/init/main.c @@ -592,6 +592,7 @@ asmlinkage void __init start_kernel(void * These use large bootmem allocations and must precede * kmem_cache_init() */ + setup_log_buf(); pidhash_init(); vfs_caches_init_early(); sort_main_extable(); --- linux.orig/kernel/printk.c +++ linux/kernel/printk.c @@ -162,46 +162,65 @@ void log_buf_kexec_setup(void) } #endif +static unsigned long __initdata new_log_buf_len; static int __init log_buf_len_setup(char *str) { unsigned size = memparse(str, &str); - unsigned long flags; if (size) size = roundup_pow_of_two(size); - if (size > log_buf_len) { - unsigned start, dest_idx, offset; - char *new_log_buf; - - new_log_buf = alloc_bootmem(size); - if (!new_log_buf) { - printk(KERN_WARNING "log_buf_len: allocation failed\n"); - goto out; - } - - spin_lock_irqsave(&logbuf_lock, flags); - log_buf_len = size; - log_buf = new_log_buf; - - offset = start = min(con_start, log_start); - dest_idx = 0; - while (start != log_end) { - log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)]; - start++; - dest_idx++; - } - log_start -= offset; - con_start -= offset; - log_end -= offset; - spin_unlock_irqrestore(&logbuf_lock, flags); + if (size > log_buf_len) + new_log_buf_len = size; - printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len); - } -out: - return 1; + return 0; } +early_param("log_buf_len", log_buf_len_setup); -__setup("log_buf_len=", log_buf_len_setup); +void __init setup_log_buf(void) +{ + unsigned long flags; + unsigned start, dest_idx, offset; + char *new_log_buf; + char first_line[64], *first_nl; + + if (!new_log_buf_len) + return; + + new_log_buf = alloc_bootmem(new_log_buf_len); + memset(first_line, 0, sizeof(first_line));use x86_memblock_find_range in x86 code? you can do that much earlier before SRAT etc is parsed. Thanks Yinghai
I could investigate that, but I didn't want to be too arch-specific. Also, we need to backport this to 2.6.32 for the kernel we support on UV (I ported the changes forward to 2.6.38). I thought this would be a very clean interface without any permanent overhead (all in __init sections), and easily supported on all arches. Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
