[PATCH] clean up kernel messages

Arrange for all kernel printks to be no-ops. Only available if CONFIG_EMBEDDED. This patch saves about 375k on my laptop config and nearly 100k on minimal configs.

Matt Mackall committed 21 years ago

Commit d59745c1 parent cd7619d4 files · +43 −6Browse files

Unified · Split

4 files

arch/i386/kernel/head.S +2 −0
include/linux/kernel.h +9 −0
init/Kconfig +11 −0
kernel/printk.c +21 −6

arch/i386/kernel/head.S+2−0

@@ -380,6 +380,7 @@ rp_sidt: · 379 unmodified lines
380	380	ALIGN
381	381	ignore_int:
382	382	cld
	383	+#ifdef CONFIG_PRINTK
383	384	pushl %eax
384	385	pushl %ecx
385	386	pushl %edx
@@ -400,6 +401,7 @@ ignore_int: · 14 unmodified lines
400	401	popl %edx
401	402	popl %ecx
402	403	popl %eax
	404	+#endif
403	405	iret
404	406
405	407	/*

include/linux/kernel.h+9−0

@@ -115,10 +115,19 @@ extern int __kernel_text_address(unsigned long addr); · 114 unmodified lines
115	115	extern int kernel_text_address(unsigned long addr);
116	116	extern int session_of_pgrp(int pgrp);
117	117
	118	+#ifdef CONFIG_PRINTK
118	119	asmlinkage int vprintk(const char *fmt, va_list args)
119	120	__attribute__ ((format (printf, 1, 0)));
120	121	asmlinkage int printk(const char * fmt, ...)
121	122	__attribute__ ((format (printf, 1, 2)));
	123	+#else
	124	+static inline int vprintk(const char *s, va_list args)
	125	+ __attribute__ ((format (printf, 1, 0)));
	126	+static inline int vprintk(const char *s, va_list args) { return 0; }
	127	+static inline int printk(const char *s, ...)
	128	+ __attribute__ ((format (printf, 1, 2)));
	129	+static inline int printk(const char *s, ...) { return 0; }
	130	+#endif
122	131
123	132	unsigned long int_sqrt(unsigned long);
124	133

init/Kconfig+11−0

@@ -275,6 +275,17 @@ config KALLSYMS_EXTRA_PASS · 274 unmodified lines
275	275	reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
276	276	you wait for kallsyms to be fixed.
277	277
	278	+
	279	+config PRINTK
	280	+ default y
	281	+ bool "Enable support for printk" if EMBEDDED
	282	+ help
	283	+ This option enables normal printk support. Removing it
	284	+ eliminates most of the message strings from the kernel image
	285	+ and makes the kernel more or less silent. As this makes it
	286	+ very difficult to diagnose system problems, saying N here is
	287	+ strongly discouraged.
	288	+
278	289	config BUG
279	290	bool "BUG() support" if EMBEDDED
280	291	default y

kernel/printk.c+21−6

@@ -85,10 +85,6 @@ static int console_locked; · 84 unmodified lines
85	85	*/
86	86	static DEFINE_SPINLOCK(logbuf_lock);
87	87
88		−static char __log_buf[__LOG_BUF_LEN];
89		−static char *log_buf = __log_buf;
90		−static int log_buf_len = __LOG_BUF_LEN;
91		−
92	88	#define LOG_BUF_MASK (log_buf_len-1)
93	89	#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
94	90
@@ -99,7 +95,6 @@ static int log_buf_len = __LOG_BUF_LEN; · 4 unmodified lines
99	95	static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */
100	96	static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */
101	97	static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */
102		−static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
103	98
104	99	/*
105	100	* Array of consoles built from command line options (console=)
@@ -120,6 +115,13 @@ static int preferred_console = -1; · 14 unmodified lines
120	115	/* Flag: console code may call schedule() */
121	116	static int console_may_schedule;
122	117
	118	+#ifdef CONFIG_PRINTK
	119	+
	120	+static char __log_buf[__LOG_BUF_LEN];
	121	+static char *log_buf = __log_buf;
	122	+static int log_buf_len = __LOG_BUF_LEN;
	123	+static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
	124	+
123	125	/*
124	126	* Setup a list of consoles. Called from init/main.c
125	127	*/
@@ -535,6 +537,7 @@ __setup("time", printk_time_setup); · 409 unmodified lines
535	537	* then changes console_loglevel may break. This is because console_loglevel
536	538	* is inspected when the actual printing occurs.
537	539	*/
	540	+
538	541	asmlinkage int printk(const char *fmt, ...)
539	542	{
540	543	va_list args;
@@ -655,6 +658,18 @@ out: · 114 unmodified lines
655	658	EXPORT_SYMBOL(printk);
656	659	EXPORT_SYMBOL(vprintk);
657	660
	661	+#else
	662	+
	663	+asmlinkage long sys_syslog(int type, char __user * buf, int len)
	664	+{
	665	+ return 0;
	666	+}
	667	+
	668	+int do_syslog(int type, char __user * buf, int len) { return 0; }
	669	+static void call_console_drivers(unsigned long start, unsigned long end) {}
	670	+
	671	+#endif
	672	+
658	673	/**
659	674	* acquire_console_sem - lock the console system for exclusive use.
660	675	*
@@ -931,7 +946,7 @@ int unregister_console(struct console * console) · 270 unmodified lines
931	946	return res;
932	947	}
933	948	EXPORT_SYMBOL(unregister_console);
934		−
	949	+
935	950	/**
936	951	* tty_write_message - write a message to a certain tty, not just the console.
937	952	*