Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758779Ab1DYSLk (ORCPT ); Mon, 25 Apr 2011 14:11:40 -0400 Received: from relay2.sgi.com ([192.48.179.30]:34833 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756078Ab1DYSLi (ORCPT ); Mon, 25 Apr 2011 14:11:38 -0400 Message-Id: <20110425181136.342333648@gulag1.americas.sgi.com> References: <20110425181136.055235992@gulag1.americas.sgi.com> User-Agent: quilt/0.46-1 Date: Mon, 25 Apr 2011 13:11:38 -0500 From: Mike Travis To: Ingo Molnar , Yinghai Lu Cc: Andrew Morton , "H. Peter Anvin" , Jack Steiner , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] printk: Allocate kernel log buffer earlier v2 Content-Disposition: inline; filename=get_log_buff_early Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4732 Lines: 181 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. Signed-off-by: Mike Travis --- arch/x86/kernel/setup.c | 2 + include/linux/printk.h | 4 ++ init/main.c | 1 kernel/printk.c | 91 +++++++++++++++++++++++++++++++----------------- 4 files changed, 67 insertions(+), 31 deletions(-) --- linux.orig/arch/x86/kernel/setup.c +++ linux/arch/x86/kernel/setup.c @@ -975,6 +975,8 @@ 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(); --- linux.orig/include/linux/printk.h +++ linux/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[]; @@ -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(int early); + 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(0); pidhash_init(); vfs_caches_init_early(); sort_main_extable(); --- linux.orig/kernel/printk.c +++ linux/kernel/printk.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -162,46 +163,74 @@ 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; - - 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(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; + + 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); + + 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 -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/