From patchwork Sat Feb 19 02:47:11 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Travis X-Patchwork-Id: 574291 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p1J2lTOr024641 for ; Sat, 19 Feb 2011 02:47:43 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755175Ab1BSCrb (ORCPT ); Fri, 18 Feb 2011 21:47:31 -0500 Received: from relay3.sgi.com ([192.48.152.1]:42554 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753504Ab1BSCrL (ORCPT ); Fri, 18 Feb 2011 21:47:11 -0500 Received: from gulag1.americas.sgi.com (gulag1.americas.sgi.com [128.162.236.41]) by relay3.corp.sgi.com (Postfix) with ESMTP id 12441AC012; Fri, 18 Feb 2011 18:47:10 -0800 (PST) Received: by gulag1.americas.sgi.com (Postfix, from userid 5508) id 60AA51037A640; Fri, 18 Feb 2011 20:47:06 -0600 (CST) Message-Id: <20110219024706.263104271@gulag1.americas.sgi.com> References: <20110219024705.308511527@gulag1.americas.sgi.com> User-Agent: quilt/0.46-1 Date: Fri, 18 Feb 2011 20:47:11 -0600 From: Mike Travis To: Ingo Molnar Cc: Jack Steiner , Robin Holt , Len Brown , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , Yinghai Lu , linux-acpi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/6] printk: Allocate kernel log buffer earlier Content-Disposition: inline; filename=get_log_buff_early Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Sat, 19 Feb 2011 02:47:44 +0000 (UTC) --- 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 + 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 +162,92 @@ 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); + +/* + * Debug code to determine if early log buffer overflowed and by how much. + * Length of first line saved is arbitrary as all we need is some context + * from the that line. + */ +static char __initdata first_line[40]; + +/* Grab part of the first line from early log buf */ +static void __init fl_buf_copy(unsigned dest_idx, char c) +{ + if (dest_idx < sizeof(first_line) - 1) + first_line[dest_idx] = c; +} + +/* + * Print free bytes left in early log buffer (might be negative) + * and part of first line. + */ +static void __init fl_print_stats(unsigned dest_idx) +{ + char *first_nl; + int free = __LOG_BUF_LEN - dest_idx; + + /* + * If first line was shorter than length of first_line buffer, + * remove the newline so we don't get a blank line in the output. + */ + first_nl = strchr(first_line, '\n'); + if (first_nl) + *first_nl = '\0'; + + pr_info("early log_buf free: %d(%d%%) first line: %s\n", + free, (free * 100) / __LOG_BUF_LEN, first_line); } -__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; + + if (!new_log_buf_len) + return; + + new_log_buf = alloc_bootmem(new_log_buf_len); + + spin_lock_irqsave(&logbuf_lock, flags); + log_buf_len = new_log_buf_len; + log_buf = new_log_buf; + new_log_buf_len = 0; + + 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]; + fl_buf_copy(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); + fl_print_stats(dest_idx); +} #ifdef CONFIG_BOOT_PRINTK_DELAY