[1/4] printk: Allocate kernel log buffer earlier

Commit Message

Yinghai Lu Feb. 28, 2011, 1:34 a.m. UTC

None

Patch

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a47fe00..69b8995 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -974,6 +974,11 @@  void __init setup_arch(char **cmdline_p)
 	memblock.current_limit = get_max_mapped();
 
 	/*
+	 * Allocate bigger log buffer as early as possible
+	 */
+	setup_log_buf();
+
+	/*
 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
 	 */
 
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 62a10c2..c3ade22 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -2,6 +2,8 @@ 
 #define _LINUX_MEMBLOCK_H
 #ifdef __KERNEL__
 
+#define MEMBLOCK_ERROR		0
+
 #ifdef CONFIG_HAVE_MEMBLOCK
 /*
  * Logical memory blocks.
@@ -20,7 +22,6 @@ 
 #include <asm/memblock.h>
 
 #define INIT_MEMBLOCK_REGIONS	128
-#define MEMBLOCK_ERROR		0
 
 struct memblock_region {
 	phys_addr_t base;
@@ -160,6 +161,12 @@  static inline unsigned long memblock_region_reserved_end_pfn(const struct memblo
 #define __initdata_memblock
 #endif
 
+#else
+static inline phys_addr_t memblock_alloc(phys_addr_t size, phys_addr_t align)
+{
+	return MEMBLOCK_ERROR;
+}
+
 #endif /* CONFIG_HAVE_MEMBLOCK */
 
 #endif /* __KERNEL__ */
diff --git a/include/linux/printk.h b/include/linux/printk.h
index ee048e7..fd266a8 100644
--- a/include/linux/printk.h
+++ b/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);
 
diff --git a/init/main.c b/init/main.c
index 33c37c3..2085bb3 100644
--- a/init/main.c
+++ b/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();
diff --git a/kernel/printk.c b/kernel/printk.c
index 3623152..14fa4d0 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -31,6 +31,7 @@ 
 #include <linux/smp.h>
 #include <linux/security.h>
 #include <linux/bootmem.h>
+#include <linux/memblock.h>
 #include <linux/syscalls.h>
 #include <linux/kexec.h>
 #include <linux/kdb.h>
@@ -162,46 +163,64 @@  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(void)
+{
+	unsigned long flags;
+	unsigned start, dest_idx, offset;
+	char *new_log_buf;
+	phys_addr_t new_addr;
+	int free;
+
+	if (!new_log_buf_len)
+		return;
 
-		printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
+	new_addr = memblock_alloc(new_log_buf_len, PAGE_SIZE);
+	if (new_addr != MEMBLOCK_ERROR)
+		new_log_buf = __va(new_addr);
+	else
+		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;
+	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++;
 	}
-out:
-	return 1;
-}
+	log_start -= offset;
+	con_start -= offset;
+	log_end -= offset;
+	spin_unlock_irqrestore(&logbuf_lock, flags);
 
-__setup("log_buf_len=", log_buf_len_setup);
+	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