It can be difficult to sort printk out if multiple processors are printing simultaneously. Add the processor number to the printk output to allow the messages to be sorted.
Signed-off-by: John Ogness <[email protected]> --- kernel/printk/printk.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index b97d4195b09a..cde036d8487a 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -331,6 +331,7 @@ enum log_flags { struct printk_log { u64 ts_nsec; /* timestamp in nanoseconds */ + u16 cpu; /* cpu that generated record */ u16 len; /* length of entire record */ u16 text_len; /* length of text buffer */ u16 dict_len; /* length of dictionary buffer */ @@ -475,7 +476,7 @@ static u32 log_next(u32 idx) /* insert record into the buffer, discard old ones, update heads */ static int log_store(int facility, int level, - enum log_flags flags, u64 ts_nsec, + enum log_flags flags, u64 ts_nsec, u16 cpu, const char *dict, u16 dict_len, const char *text, u16 text_len) { @@ -506,6 +507,7 @@ static int log_store(int facility, int level, msg->level = level & 7; msg->flags = flags & 0x1f; msg->ts_nsec = ts_nsec; + msg->cpu = cpu; msg->len = size; /* insert message */ @@ -570,9 +572,9 @@ static ssize_t msg_print_ext_header(char *buf, size_t size, do_div(ts_usec, 1000); - return scnprintf(buf, size, "%u,%llu,%llu,%c;", + return scnprintf(buf, size, "%u,%llu,%llu,%c,%hu;", (msg->facility << 3) | msg->level, seq, ts_usec, - msg->flags & LOG_CONT ? 'c' : '-'); + msg->flags & LOG_CONT ? 'c' : '-', msg->cpu); } static ssize_t msg_print_ext_body(char *buf, size_t size, @@ -1110,6 +1112,11 @@ static inline void boot_delay_msec(int level) static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); +static size_t print_cpu(u16 cpu, char *buf) +{ + return sprintf(buf, "%03hu: ", cpu); +} + static size_t print_syslog(unsigned int level, char *buf) { return sprintf(buf, "<%u>", level); @@ -1132,6 +1139,7 @@ static size_t print_prefix(const struct printk_log *msg, bool syslog, len = print_syslog((msg->facility << 3) | msg->level, buf); if (time) len += print_time(msg->ts_nsec, buf + len); + len += print_cpu(msg->cpu, buf + len); return len; } @@ -1698,6 +1706,7 @@ asmlinkage int vprintk_emit(int facility, int level, u64 ts_nsec; char *text; char *rbuf; + int cpu; ts_nsec = local_clock(); @@ -1707,6 +1716,8 @@ asmlinkage int vprintk_emit(int facility, int level, return printed_len; } + cpu = raw_smp_processor_id(); + text = rbuf; text_len = vscnprintf(text, PRINTK_SPRINT_MAX, fmt, args); @@ -1744,7 +1755,7 @@ asmlinkage int vprintk_emit(int facility, int level, if (dict) lflags |= LOG_PREFIX|LOG_NEWLINE; - printed_len = log_store(facility, level, lflags, ts_nsec, + printed_len = log_store(facility, level, lflags, ts_nsec, cpu, dict, dictlen, text, text_len); prb_commit(&h); -- 2.11.0
