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Remove global log buffer feature entirely

Browse Source 
A earlier commit changed the global log buffer so that it only
records messages that are explicitly requested via the log
filters setting. This removes the performance burden, and
improves the signal/noise ratio for messages in the global
buffer. At the same time though, it is somewhat pointless, since
all the recorded log messages are already going to be sent to an
explicit log output like syslog, stderr or the journal. The
global log buffer is thus just duplicating this data on stderr
upon crash.

The log_buffer_size config parameter is left in the augeas
lens to prevent breakage for users on upgrade. It is however
completely ignored hereafter.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange 2014-03-03 14:54:33 +00:00
parent 975b2392c3
commit c0c8c1d7bb
14 changed files with 17 additions and 342 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
daemon/libvirtd-config.c
View File

@ -268,8 +268,6 @@ daemonConfigNew(bool privileged ATTRIBUTE_UNUSED)
data->max_requests = 20;
data->max_client_requests = 5;
data->log_buffer_size = 64;
data->audit_level = 1;
data->audit_logging = 0;
@ -433,7 +431,6 @@ daemonConfigLoadOptions(struct daemonConfig *data,
GET_CONF_INT(conf, filename, log_level);
GET_CONF_STR(conf, filename, log_filters);
GET_CONF_STR(conf, filename, log_outputs);
GET_CONF_INT(conf, filename, log_buffer_size);
GET_CONF_INT(conf, filename, keepalive_interval);
GET_CONF_INT(conf, filename, keepalive_count);

1
daemon/libvirtd-config.h
View File

@ -74,7 +74,6 @@ struct daemonConfig {
int log_level;
char *log_filters;
char *log_outputs;
int log_buffer_size;
int audit_level;
int audit_logging;

2
daemon/libvirtd.c
View File

@ -662,8 +662,6 @@ daemonSetupLogging(struct daemonConfig *config,
virLogSetFromEnv();
virLogSetBufferSize(config->log_buffer_size);
if (virLogGetNbFilters() == 0)
virLogParseFilters(config->log_filters);

10
daemon/libvirtd.conf
View File

@ -349,11 +349,11 @@
#log_outputs="3:syslog:libvirtd"
#
# Log debug buffer size: default 64
# The daemon keeps an internal debug log buffer which will be dumped in case
# of crash or upon receiving a SIGUSR2 signal. This setting allows to override
# the default buffer size in kilobytes.
# If value is 0 or less the debug log buffer is deactivated
# Log debug buffer size:
#
# This configuration option is no longer used, since the global
# log buffer functionality has been removed. Please configure
# suitable log_outputs/log_filters settings to obtain logs.
#log_buffer_size = 64

10
docs/logging.html.in
View File

@ -38,12 +38,6 @@
all messages to a debugging file but only allow errors to be
logged through syslog.</li>
</ul>
<p>Note that the logging module saves all logs to a <b>debug buffer</b>
filled in a round-robin fashion as to keep a full log of the
recent logs including all debug. The debug buffer can be resized
or deactivated in the daemon using the log_buffer_size variable,
default is 64 kB. This can be used when debugging the library
(see the virLogBuffer variable content).</p>
<h2>
<a name="log_config">Configuring logging in the library</a>
@ -245,9 +239,5 @@ log_outputs="1:file:/var/log/libvirt/libvirtd.log"</pre>
<p>in libvirtd.conf and restart the daemon will allow to
gather a copious amount of debugging traces for the operations done
in those areas.</p>
<p>On the other hand to deactivate the logbuffer in the daemon
for stable high load servers, set</p>
<pre>log_buffer_size=0</pre>
<p>in the libvirtd.conf.</p>
</body>
</html>

2
src/libvirt_private.syms
View File

@ -1448,7 +1448,6 @@ virLockSpaceReleaseResourcesForOwner;
# util/virlog.h
virLogDefineFilter;
virLogDefineOutput;
virLogEmergencyDumpAll;
virLogGetDefaultPriority;
virLogGetFilters;
virLogGetNbFilters;
@ -1462,7 +1461,6 @@ virLogParseOutputs;
virLogPriorityFromSyslog;
virLogProbablyLogMessage;
virLogReset;
virLogSetBufferSize;
virLogSetDefaultPriority;
virLogSetFromEnv;
virLogUnlock;

2
src/locking/lock_daemon.c
View File

@ -478,8 +478,6 @@ virLockDaemonSetupLogging(virLockDaemonConfigPtr config,
virLogSetFromEnv();
virLogSetBufferSize(config->log_buffer_size);
if (virLogGetNbFilters() == 0)
virLogParseFilters(config->log_filters);

2
src/locking/lock_daemon_config.c
View File

@ -115,7 +115,6 @@ virLockDaemonConfigNew(bool privileged ATTRIBUTE_UNUSED)
if (VIR_ALLOC(data) < 0)
return NULL;
data->log_buffer_size = 64;
data->max_clients = 1024;
return data;
@ -141,7 +140,6 @@ virLockDaemonConfigLoadOptions(virLockDaemonConfigPtr data,
GET_CONF_INT(conf, filename, log_level);
GET_CONF_STR(conf, filename, log_filters);
GET_CONF_STR(conf, filename, log_outputs);
GET_CONF_INT(conf, filename, log_buffer_size);
GET_CONF_INT(conf, filename, max_clients);
return 0;

1
src/locking/lock_daemon_config.h
View File

@ -33,7 +33,6 @@ struct _virLockDaemonConfig {
int log_level;
char *log_filters;
char *log_outputs;
int log_buffer_size;
int max_clients;
};

10
src/locking/virtlockd.conf
View File

@ -52,11 +52,11 @@
#log_outputs="3:syslog:virtlockd"
#
# Log debug buffer size: default 64
# The daemon keeps an internal debug log buffer which will be dumped in case
# of crash or upon receiving a SIGUSR2 signal. This setting allows to override
# the default buffer size in kilobytes.
# If value is 0 or less the debug log buffer is deactivated
# Log debug buffer size:
#
# This configuration option is no longer used, since the global
# log buffer functionality has been removed. Please configure
# suitable log_outputs/log_filters settings to obtain logs.
#log_buffer_size = 64
# The maximum number of concurrent client connections to allow

45
src/rpc/virnetserver.c
View File

@ -341,34 +341,6 @@ static int virNetServerDispatchNewClient(virNetServerServicePtr svc,
}
static void
virNetServerFatalSignal(int sig, siginfo_t *siginfo ATTRIBUTE_UNUSED,
void *context ATTRIBUTE_UNUSED)
{
struct sigaction sig_action;
int origerrno;
origerrno = errno;
virLogEmergencyDumpAll(sig);
/*
* If the signal is fatal, avoid looping over this handler
* by deactivating it
*/
#ifdef SIGUSR2
if (sig != SIGUSR2) {
#endif
memset(&sig_action, 0, sizeof(sig_action));
sig_action.sa_handler = SIG_DFL;
sigaction(sig, &sig_action, NULL);
raise(sig);
#ifdef SIGUSR2
}
#endif
errno = origerrno;
}
virNetServerPtr virNetServerNew(size_t min_workers,
size_t max_workers,
size_t priority_workers,
@ -429,23 +401,6 @@ virNetServerPtr virNetServerNew(size_t min_workers,
sig_action.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sig_action, NULL);
/*
* catch fatal errors to dump a log, also hook to USR2 for dynamic
* debugging purposes or testing
*/
sig_action.sa_sigaction = virNetServerFatalSignal;
sig_action.sa_flags = SA_SIGINFO;
sigaction(SIGFPE, &sig_action, NULL);
sigaction(SIGSEGV, &sig_action, NULL);
sigaction(SIGILL, &sig_action, NULL);
sigaction(SIGABRT, &sig_action, NULL);
#ifdef SIGBUS
sigaction(SIGBUS, &sig_action, NULL);
#endif
#ifdef SIGUSR2
sigaction(SIGUSR2, &sig_action, NULL);
#endif
return srv;
error:

266
src/util/virlog.c
View File

@ -30,7 +30,6 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <execinfo.h>
#include <regex.h>
#if HAVE_SYSLOG_H
@ -62,15 +61,6 @@
VIR_LOG_INIT("util.log");
/*
* A logging buffer to keep some history over logs
*/
static int virLogSize = 64 * 1024;
static char *virLogBuffer = NULL;
static int virLogLen = 0;
static int virLogStart = 0;
static int virLogEnd = 0;
static regex_t *virLogRegex = NULL;
@ -194,29 +184,10 @@ virLogPriorityString(virLogPriority lvl)
static int
virLogOnceInit(void)
{
const char *pbm = NULL;
if (virMutexInit(&virLogMutex) < 0)
return -1;
virLogLock();
if (VIR_ALLOC_N_QUIET(virLogBuffer, virLogSize + 1) < 0) {
/*
* The debug buffer is not a critical component, allow startup
* even in case of failure to allocate it in case of a
* configuration mistake.
*/
virLogSize = 64 * 1024;
if (VIR_ALLOC_N_QUIET(virLogBuffer, virLogSize + 1) < 0) {
pbm = "Failed to allocate debug buffer: deactivating debug log\n";
virLogSize = 0;
} else {
pbm = "Failed to allocate debug buffer: reduced to 64 kB\n";
}
}
virLogLen = 0;
virLogStart = 0;
virLogEnd = 0;
virLogDefaultPriority = VIR_LOG_DEFAULT;
if (VIR_ALLOC_QUIET(virLogRegex) >= 0) {
@ -225,73 +196,12 @@ virLogOnceInit(void)
}
virLogUnlock();
if (pbm)
VIR_WARN("%s", pbm);
return 0;
}
VIR_ONCE_GLOBAL_INIT(virLog)
/**
* virLogSetBufferSize:
* @size: size of the buffer in kilobytes or <= 0 to deactivate
*
* Dynamically set the size or deactivate the logging buffer used to keep
* a trace of all recent debug output. Note that the content of the buffer
* is lost if it gets reallocated.
*
* Return -1 in case of failure or 0 in case of success
*/
int
virLogSetBufferSize(int size)
{
int ret = 0;
int oldsize;
char *oldLogBuffer;
const char *pbm = NULL;
if (size < 0)
size = 0;
if (virLogInitialize() < 0)
return -1;
if (size * 1024 == virLogSize)
return ret;
virLogLock();
oldsize = virLogSize;
oldLogBuffer = virLogBuffer;
if (INT_MAX / 1024 <= size) {
pbm = "Requested log size of %d kB too large\n";
ret = -1;
goto error;
}
virLogSize = size * 1024;
if (VIR_ALLOC_N_QUIET(virLogBuffer, virLogSize + 1) < 0) {
pbm = "Failed to allocate debug buffer of %d kB\n";
virLogBuffer = oldLogBuffer;
virLogSize = oldsize;
ret = -1;
goto error;
}
VIR_FREE(oldLogBuffer);
virLogLen = 0;
virLogStart = 0;
virLogEnd = 0;
error:
virLogUnlock();
if (pbm)
VIR_ERROR(pbm, size);
return ret;
}
/**
* virLogReset:
*
@ -308,172 +218,11 @@ virLogReset(void)
virLogLock();
virLogResetFilters();
virLogResetOutputs();
virLogLen = 0;
virLogStart = 0;
virLogEnd = 0;
virLogDefaultPriority = VIR_LOG_DEFAULT;
virLogUnlock();
return 0;
}
/*
* Store a string in the ring buffer
*/
static void
virLogStr(const char *str)
{
int tmp;
int len;
if ((str == NULL) || (virLogBuffer == NULL) || (virLogSize <= 0))
return;
len = strlen(str);
if (len >= virLogSize)
return;
/*
* copy the data and reset the end, we cycle over the end of the buffer
*/
if (virLogEnd + len >= virLogSize) {
tmp = virLogSize - virLogEnd;
memcpy(&virLogBuffer[virLogEnd], str, tmp);
memcpy(&virLogBuffer[0], &str[tmp], len - tmp);
virLogEnd = len - tmp;
} else {
memcpy(&virLogBuffer[virLogEnd], str, len);
virLogEnd += len;
}
virLogBuffer[virLogEnd] = 0;
/*
* Update the log length, and if full move the start index
*/
virLogLen += len;
if (virLogLen > virLogSize) {
tmp = virLogLen - virLogSize;
virLogLen = virLogSize;
virLogStart += tmp;
if (virLogStart >= virLogSize)
virLogStart -= virLogSize;
}
}
static void
virLogDumpAllFD(const char *msg, int len)
{
size_t i;
bool found = false;
if (len <= 0)
len = strlen(msg);
for (i = 0; i < virLogNbOutputs; i++) {
if (virLogOutputs[i].f == virLogOutputToFd) {
int fd = (intptr_t) virLogOutputs[i].data;
if (fd >= 0) {
ignore_value(safewrite(fd, msg, len));
found = true;
}
}
}
if (!found)
ignore_value(safewrite(STDERR_FILENO, msg, len));
}
/**
* virLogEmergencyDumpAll:
* @signum: the signal number
*
* Emergency function called, possibly from a signal handler.
* It need to output the debug ring buffer through the log
* output which are safe to use from a signal handler.
* In case none is found it is emitted to standard error.
*/
void
virLogEmergencyDumpAll(int signum)
{
int len;
int oldLogStart, oldLogLen;
switch (signum) {
#ifdef SIGFPE
case SIGFPE:
virLogDumpAllFD("Caught signal Floating-point exception", -1);
break;
#endif
#ifdef SIGSEGV
case SIGSEGV:
virLogDumpAllFD("Caught Segmentation violation", -1);
break;
#endif
#ifdef SIGILL
case SIGILL:
virLogDumpAllFD("Caught illegal instruction", -1);
break;
#endif
#ifdef SIGABRT
case SIGABRT:
virLogDumpAllFD("Caught abort signal", -1);
break;
#endif
#ifdef SIGBUS
case SIGBUS:
virLogDumpAllFD("Caught bus error", -1);
break;
#endif
#ifdef SIGUSR2
case SIGUSR2:
virLogDumpAllFD("Caught User-defined signal 2", -1);
break;
#endif
default:
virLogDumpAllFD("Caught unexpected signal", -1);
break;
}
if ((virLogBuffer == NULL) || (virLogSize <= 0)) {
virLogDumpAllFD(" internal log buffer deactivated\n", -1);
return;
}
virLogDumpAllFD(" dumping internal log buffer:\n", -1);
virLogDumpAllFD("\n\n ====== start of log =====\n\n", -1);
/*
* Since we can't lock the buffer safely from a signal handler
* we mark it as empty in case of concurrent access, and proceed
* with the data, at worse we will output something a bit weird
* if another thread start logging messages at the same time.
* Note that virLogStr() uses virLogEnd for the computations and
* writes to the buffer and only then updates virLogLen and virLogStart
* so it's best to reset it first.
*/
oldLogStart = virLogStart;
oldLogLen = virLogLen;
virLogEnd = 0;
virLogLen = 0;
virLogStart = 0;
while (oldLogLen > 0) {
if (oldLogStart + oldLogLen < virLogSize) {
virLogBuffer[oldLogStart + oldLogLen] = 0;
virLogDumpAllFD(&virLogBuffer[oldLogStart], oldLogLen);
oldLogStart += oldLogLen;
oldLogLen = 0;
} else {
len = virLogSize - oldLogStart;
virLogBuffer[virLogSize] = 0;
virLogDumpAllFD(&virLogBuffer[oldLogStart], len);
oldLogLen -= len;
oldLogStart = 0;
}
}
virLogDumpAllFD("\n\n ====== end of log =====\n\n", -1);
}
/**
* virLogSetDefaultPriority:
* @priority: the default priority level
@ -840,19 +589,12 @@ virLogVMessage(virLogSourcePtr source,
if (virTimeStringNowRaw(timestamp) < 0)
timestamp[0] = '\0';
/*
* Log based on defaults, first store in the history buffer,
* then if emit push the message on the outputs defined, if none
* use stderr.
* NOTE: the locking is a single point of contention for multiple
* threads, but avoid intermixing. Maybe set up locks per output
* to improve paralellism.
*/
virLogLock();
virLogStr(timestamp);
virLogStr(": ");
virLogStr(msg);
/*
* Push the message to the outputs defined, if none exist then
* use stderr.
*/
for (i = 0; i < virLogNbOutputs; i++) {
if (priority >= virLogOutputs[i].priority) {
if (virLogOutputs[i].logVersion) {

2
src/util/virlog.h
View File

@ -200,8 +200,6 @@ extern void virLogVMessage(virLogSourcePtr source,
virLogMetadataPtr metadata,
const char *fmt,
va_list vargs) ATTRIBUTE_FMT_PRINTF(7, 0);
extern int virLogSetBufferSize(int size);
extern void virLogEmergencyDumpAll(int signum);
bool virLogProbablyLogMessage(const char *str);

3
tests/libvirtdconftest.c
View File

@ -225,6 +225,9 @@ mymain(void)
VIR_DEBUG("Initial config [%s]", filedata);
for (i = 0; params[i] != 0; i++) {
const struct testCorruptData data = { params, filedata, filename, i };
/* Skip now ignored config param */
if (STRPREFIX(filedata + params[i], "log_buffer_size"))
continue;
if (virtTestRun("Test corruption", testCorrupt, &data) < 0)
ret = -1;
}