Before commit 32d07f5e59f2 ("passt, pasta: Completely avoid dynamic
memory allocation"), we didn't store the current log mask in a
variable, and we fetched it using setlogmask(0) wherever needed.
But after that commit, we can use our log_mask copy instead. And we
should: with recent glibc versions, setlogmask(0) actually results in
a system call, which causes a substantial overhead with high transfer
rates: we use setlogmask(0) even to decide we don't want to print
debug messages.
Now that we rely on log_mask in early stages, before setlogmask() is
called, we need to initialise that variable to the special LOG_EMERG
mask value right away: define LOG_EARLY to make this clearer, and,
while at it, group conditions in vlogmsg() into something more terse.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
v3: Include changes to passt.c I accidentally didn't commit in v2
v2: Initialise log_mask so that prints before the first
__setlogmask() call still work.
log.c | 18 ++++++++++--------
passt.c | 7 ++-----
2 files changed, 12 insertions(+), 13 deletions(-)
diff --git a/log.c b/log.c
index 4a70e29..eafaca2 100644
--- a/log.c
+++ b/log.c
@@ -30,9 +30,12 @@
#include "util.h"
#include "passt.h"
+/* LOG_EARLY means we don't know yet: log everything. LOG_EMERG is unused */
+#define LOG_EARLY LOG_MASK(LOG_EMERG)
+
static int log_sock = -1; /* Optional socket to system logger */
static char log_ident[BUFSIZ]; /* Identifier string for openlog() */
-static int log_mask; /* Current log priority mask */
+static int log_mask = LOG_EARLY; /* Current log priority mask */
static int log_opt; /* Options for openlog() */
static int log_file = -1; /* Optional log file descriptor */
@@ -45,34 +48,33 @@ static time_t log_start; /* Start timestamp */
int log_trace; /* --trace mode enabled */
int log_to_stdout; /* Print to stdout instead of stderr */
-#define BEFORE_DAEMON (setlogmask(0) == LOG_MASK(LOG_EMERG))
-
void vlogmsg(int pri, const char *format, va_list ap)
{
+ bool debug_print = (log_mask & LOG_MASK(LOG_DEBUG)) && log_file == -1;
+ bool early_print = LOG_PRI(log_mask) == LOG_EARLY;
FILE *out = log_to_stdout ? stdout : stderr;
struct timespec tp;
- if (setlogmask(0) & LOG_MASK(LOG_DEBUG) && log_file == -1) {
+ if (debug_print) {
clock_gettime(CLOCK_REALTIME, &tp);
fprintf(out, "%lli.%04lli: ",
(long long int)tp.tv_sec - log_start,
(long long int)tp.tv_nsec / (100L * 1000));
}
- if ((LOG_MASK(LOG_PRI(pri)) & log_mask) || BEFORE_DAEMON) {
+ if ((log_mask & LOG_MASK(LOG_PRI(pri))) || early_print) {
va_list ap2;
va_copy(ap2, ap); /* Don't clobber ap, we need it again */
if (log_file != -1)
logfile_write(pri, format, ap2);
- else if (!(setlogmask(0) & LOG_MASK(LOG_DEBUG)))
+ else if (!(log_mask & LOG_MASK(LOG_DEBUG)))
passt_vsyslog(pri, format, ap2);
va_end(ap2);
}
- if ((setlogmask(0) & LOG_MASK(LOG_DEBUG) && log_file == -1) ||
- (BEFORE_DAEMON && !(log_opt & LOG_PERROR))) {
+ if (debug_print || (early_print && !(log_opt & LOG_PERROR))) {
(void)vfprintf(out, format, ap);
if (format[strlen(format)] != '\n')
fprintf(out, "\n");
diff --git a/passt.c b/passt.c
index 44d3a0b..aaa8e58 100644
--- a/passt.c
+++ b/passt.c
@@ -251,9 +251,6 @@ int main(int argc, char **argv)
__openlog(log_name, 0, LOG_DAEMON);
- /* Meaning we don't know yet: log everything. LOG_EMERG is unused */
- __setlogmask(LOG_MASK(LOG_EMERG));
-
c.epollfd = epoll_create1(EPOLL_CLOEXEC);
if (c.epollfd == -1) {
perror("epoll_create1");
@@ -322,8 +319,8 @@ int main(int argc, char **argv)
if (isolate_prefork(&c))
die("Failed to sandbox process, exiting");
- /* Once the log mask is not LOG_EMERG, we will no longer
- * log to stderr if there was a log file specified.
+ /* Once the log mask is not LOG_EARLY, we will no longer log to stderr
+ * if there was a log file specified.
*/
if (c.debug)
__setlogmask(LOG_UPTO(LOG_DEBUG));
--
2.39.2