From 162a7e7500f9664636e649ba59defe541b7c2c60 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 24 May 2011 17:13:20 -0700 Subject: [PATCH 1/1] printk: allocate kernel log buffer earlier 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. On kernels without memblock, a later call to setup_log_buf from kernel/init.c is the fallback. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_PRINTK=n build] Signed-off-by: Mike Travis Cc: Yinghai Lu Cc: "H. Peter Anvin" Cc: Jack Steiner Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/kernel/setup.c | 2 + include/linux/printk.h | 7 ++++ init/main.c | 1 + kernel/printk.c | 87 +++++++++++++++++++++++++++-------------- 4 files changed, 68 insertions(+), 29 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 605e5ae19c7f..a3e5948670c2 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -946,6 +946,8 @@ void __init setup_arch(char **cmdline_p) if (init_ohci1394_dma_early) init_ohci1394_dma_on_all_controllers(); #endif + /* Allocate bigger log buffer */ + setup_log_buf(1); reserve_initrd(); diff --git a/include/linux/printk.h b/include/linux/printk.h index ee048e77e1ae..0101d55d9651 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -1,6 +1,8 @@ #ifndef __KERNEL_PRINTK__ #define __KERNEL_PRINTK__ +#include + extern const char linux_banner[]; extern const char linux_proc_banner[]; @@ -113,6 +115,7 @@ extern int dmesg_restrict; extern int kptr_restrict; void log_buf_kexec_setup(void); +void __init setup_log_buf(int early); #else static inline __attribute__ ((format (printf, 1, 0))) int vprintk(const char *s, va_list args) @@ -137,6 +140,10 @@ static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, static inline void log_buf_kexec_setup(void) { } + +static inline void setup_log_buf(int early) +{ +} #endif extern void dump_stack(void) __cold; diff --git a/init/main.c b/init/main.c index 22da33918aef..d2f1e086bf33 100644 --- a/init/main.c +++ b/init/main.c @@ -504,6 +504,7 @@ asmlinkage void __init start_kernel(void) * These use large bootmem allocations and must precede * kmem_cache_init() */ + setup_log_buf(0); pidhash_init(); vfs_caches_init_early(); sort_main_extable(); diff --git a/kernel/printk.c b/kernel/printk.c index da8ca817eae3..35185392173f 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -167,46 +168,74 @@ void log_buf_kexec_setup(void) } #endif +/* requested log_buf_len from kernel cmdline */ +static unsigned long __initdata new_log_buf_len; + +/* save requested log_buf_len since it's too early to process it */ 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; + if (size > log_buf_len) + new_log_buf_len = size; - new_log_buf = alloc_bootmem(size); - if (!new_log_buf) { - printk(KERN_WARNING "log_buf_len: allocation failed\n"); - goto out; - } + return 0; +} +early_param("log_buf_len", log_buf_len_setup); - 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); +void __init setup_log_buf(int early) +{ + unsigned long flags; + unsigned start, dest_idx, offset; + char *new_log_buf; + int free; + + if (!new_log_buf_len) + return; + + if (early) { + unsigned long mem; - printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len); + mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); + if (mem == MEMBLOCK_ERROR) + return; + new_log_buf = __va(mem); + } else { + new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); } -out: - return 1; -} -__setup("log_buf_len=", log_buf_len_setup); + if (unlikely(!new_log_buf)) { + pr_err("log_buf_len: %ld bytes not available\n", + new_log_buf_len); + return; + } + + spin_lock_irqsave(&logbuf_lock, flags); + log_buf_len = new_log_buf_len; + log_buf = new_log_buf; + new_log_buf_len = 0; + free = __LOG_BUF_LEN - log_end; + + offset = start = min(con_start, log_start); + dest_idx = 0; + while (start != log_end) { + unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1); + + log_buf[dest_idx] = __log_buf[log_idx_mask]; + start++; + dest_idx++; + } + log_start -= offset; + con_start -= offset; + log_end -= offset; + spin_unlock_irqrestore(&logbuf_lock, flags); + + pr_info("log_buf_len: %d\n", log_buf_len); + pr_info("early log buf free: %d(%d%%)\n", + free, (free * 100) / __LOG_BUF_LEN); +} #ifdef CONFIG_BOOT_PRINTK_DELAY -- 2.34.1