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From: John Ogness <john.ogness@linutronix.de>
Date: Tue, 12 Feb 2019 15:29:55 +0100
Subject: [PATCH 17/25] printk: add processor number to output
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.10-rt7.tar.xz
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 <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/printk/printk.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
--- 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 l
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
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 l
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
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
u64 ts_nsec;
char *text;
char *rbuf;
+ int cpu;
ts_nsec = local_clock();
@@ -1707,6 +1716,8 @@ asmlinkage int vprintk_emit(int facility
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
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);
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