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
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