/*
* Copyright 2013-2019 the Pacemaker project contributors
*
* The version control history for this file may have further details.
*
* This source code is licensed under the GNU General Public License version 2
* or later (GPLv2+) WITHOUT ANY WARRANTY.
*/
#include <crm_internal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <dirent.h>
#include <crm/crm.h>
#include <crm/msg_xml.h>
#include <crm/cluster.h>
#include <pacemaker-controld.h>
/* These values don't need to be bits, but these particular values must be kept
* for backward compatibility during rolling upgrades.
*/
enum throttle_state_e {
throttle_none = 0x0000,
throttle_low = 0x0001,
throttle_med = 0x0010,
throttle_high = 0x0100,
throttle_extreme = 0x1000,
};
struct throttle_record_s {
int max;
enum throttle_state_e mode;
char *node;
};
static int throttle_job_max = 0;
static float throttle_load_target = 0.0;
#define THROTTLE_FACTOR_LOW 1.2
#define THROTTLE_FACTOR_MEDIUM 1.6
#define THROTTLE_FACTOR_HIGH 2.0
static GHashTable *throttle_records = NULL;
static mainloop_timer_t *throttle_timer = NULL;
static const char *
load2str(enum throttle_state_e mode)
{
switch (mode) {
case throttle_extreme: return "extreme";
case throttle_high: return "high";
case throttle_med: return "medium";
case throttle_low: return "low";
case throttle_none: return "negligible";
default: return "undetermined";
}
}
#if SUPPORT_PROCFS
/*!
* \internal
* \brief Return name of /proc file containing the CIB daemon's load statistics
*
* \return Newly allocated memory with file name on success, NULL otherwise
*
* \note It is the caller's responsibility to free the return value.
* This will return NULL if the daemon is being run via valgrind.
* This should be called only on Linux systems.
*/
static char *
find_cib_loadfile(void)
{
int pid = crm_procfs_pid_of("pacemaker-based");
return pid? crm_strdup_printf("/proc/%d/stat", pid) : NULL;
}
static bool
throttle_cib_load(float *load)
{
/*
/proc/[pid]/stat
Status information about the process. This is used by ps(1). It is defined in /usr/src/linux/fs/proc/array.c.
The fields, in order, with their proper scanf(3) format specifiers, are:
pid %d (1) The process ID.
comm %s (2) The filename of the executable, in parentheses. This is visible whether or not the executable is swapped out.
state %c (3) One character from the string "RSDZTW" where R is running, S is sleeping in an interruptible wait, D is waiting in uninterruptible disk sleep, Z is zombie, T is traced or stopped (on a signal), and W is paging.
ppid %d (4) The PID of the parent.
pgrp %d (5) The process group ID of the process.
session %d (6) The session ID of the process.
tty_nr %d (7) The controlling terminal of the process. (The minor device number is contained in the combination of bits 31 to 20 and 7 to 0; the major device number is in bits 15 to 8.)
tpgid %d (8) The ID of the foreground process group of the controlling terminal of the process.
flags %u (%lu before Linux 2.6.22)
(9) The kernel flags word of the process. For bit meanings, see the PF_* defines in the Linux kernel source file include/linux/sched.h. Details depend on the kernel version.
minflt %lu (10) The number of minor faults the process has made which have not required loading a memory page from disk.
cminflt %lu (11) The number of minor faults that the process's waited-for children have made.
majflt %lu (12) The number of major faults the process has made which have required loading a memory page from disk.
cmajflt %lu (13) The number of major faults that the process's waited-for children have made.
utime %lu (14) Amount of time that this process has been scheduled in user mode, measured in clock ticks (divide by sysconf(_SC_CLK_TCK)). This includes guest time, guest_time (time spent running a virtual CPU, see below), so that applications that are not aware of the guest time field do not lose that time from their calculations.
stime %lu (15) Amount of time that this process has been scheduled in kernel mode, measured in clock ticks (divide by sysconf(_SC_CLK_TCK)).
*/
static char *loadfile = NULL;
static time_t last_call = 0;
static long ticks_per_s = 0;
static unsigned long last_utime, last_stime;
char buffer[64*1024];
FILE *stream = NULL;
time_t now = time(NULL);
if(load == NULL) {
return FALSE;
} else {
*load = 0.0;
}
if(loadfile == NULL) {
last_call = 0;
last_utime = 0;
last_stime = 0;
loadfile = find_cib_loadfile();
if (loadfile == NULL) {
crm_warn("Couldn't find CIB load file");
return FALSE;
}
ticks_per_s = sysconf(_SC_CLK_TCK);
crm_trace("Found %s", loadfile);
}
stream = fopen(loadfile, "r");
if(stream == NULL) {
int rc = errno;
crm_warn("Couldn't read %s: %s (%d)", loadfile, pcmk_strerror(rc), rc);
free(loadfile); loadfile = NULL;
return FALSE;
}
if(fgets(buffer, sizeof(buffer), stream)) {
char *comm = calloc(1, 256);
char state = 0;
int rc = 0, pid = 0, ppid = 0, pgrp = 0, session = 0, tty_nr = 0, tpgid = 0;
unsigned long flags = 0, minflt = 0, cminflt = 0, majflt = 0, cmajflt = 0, utime = 0, stime = 0;
rc = sscanf(buffer, "%d %[^ ] %c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
&pid, comm, &state,
&ppid, &pgrp, &session, &tty_nr, &tpgid,
&flags, &minflt, &cminflt, &majflt, &cmajflt, &utime, &stime);
free(comm);
if(rc != 15) {
crm_err("Only %d of 15 fields found in %s", rc, loadfile);
fclose(stream);
return FALSE;
} else if(last_call > 0
&& last_call < now
&& last_utime <= utime
&& last_stime <= stime) {
time_t elapsed = now - last_call;
unsigned long delta_utime = utime - last_utime;
unsigned long delta_stime = stime - last_stime;
*load = (delta_utime + delta_stime); /* Cast to a float before division */
*load /= ticks_per_s;
*load /= elapsed;
crm_debug("cib load: %f (%lu ticks in %lds)", *load, delta_utime + delta_stime, (long)elapsed);
} else {
crm_debug("Init %lu + %lu ticks at %ld (%lu tps)", utime, stime, (long)now, ticks_per_s);
}
last_call = now;
last_utime = utime;
last_stime = stime;
fclose(stream);
return TRUE;
}
fclose(stream);
return FALSE;
}
static bool
throttle_load_avg(float *load)
{
char buffer[256];
FILE *stream = NULL;
const char *loadfile = "/proc/loadavg";
if(load == NULL) {
return FALSE;
}
stream = fopen(loadfile, "r");
if(stream == NULL) {
int rc = errno;
crm_warn("Couldn't read %s: %s (%d)", loadfile, pcmk_strerror(rc), rc);
return FALSE;
}
if(fgets(buffer, sizeof(buffer), stream)) {
char *nl = strstr(buffer, "\n");
/* Grab the 1-minute average, ignore the rest */
*load = strtof(buffer, NULL);
if(nl) { nl[0] = 0; }
fclose(stream);
return TRUE;
}
fclose(stream);
return FALSE;
}
/*!
* \internal
* \brief Check a load value against throttling thresholds
*
* \param[in] load Load value to check
* \param[in] desc Description of metric (for logging)
* \param[in] thresholds Low/medium/high/extreme thresholds
*
* \return Throttle mode corresponding to load value
*/
static enum throttle_state_e
throttle_check_thresholds(float load, const char *desc, float thresholds[4])
{
if (load > thresholds[3]) {
crm_notice("Extreme %s detected: %f", desc, load);
return throttle_extreme;
} else if (load > thresholds[2]) {
crm_notice("High %s detected: %f", desc, load);
return throttle_high;
} else if (load > thresholds[1]) {
crm_info("Moderate %s detected: %f", desc, load);
return throttle_med;
} else if (load > thresholds[0]) {
crm_debug("Noticeable %s detected: %f", desc, load);
return throttle_low;
}
crm_trace("Negligible %s detected: %f", desc, load);
return throttle_none;
}
static enum throttle_state_e
throttle_handle_load(float load, const char *desc, int cores)
{
float normalize;
float thresholds[4];
if (cores == 1) {
/* On a single core machine, a load of 1.0 is already too high */
normalize = 0.6;
} else {
/* Normalize the load to be per-core */
normalize = cores;
}
thresholds[0] = throttle_load_target * normalize * THROTTLE_FACTOR_LOW;
thresholds[1] = throttle_load_target * normalize * THROTTLE_FACTOR_MEDIUM;
thresholds[2] = throttle_load_target * normalize * THROTTLE_FACTOR_HIGH;
thresholds[3] = load + 1.0; /* never extreme */
return throttle_check_thresholds(load, desc, thresholds);
}
#endif
static enum throttle_state_e
throttle_mode(void)
{
enum throttle_state_e mode = throttle_none;
#if SUPPORT_PROCFS
unsigned int cores;
float load;
float thresholds[4];
cores = crm_procfs_num_cores();
if(throttle_cib_load(&load)) {
float cib_max_cpu = 0.95;
/* The CIB is a single-threaded task and thus cannot consume
* more than 100% of a CPU (and 1/cores of the overall system
* load).
*
* On a many-cored system, the CIB might therefore be maxed out
* (causing operations to fail or appear to fail) even though
* the overall system load is still reasonable.
*
* Therefore, the 'normal' thresholds can not apply here, and we
* need a special case.
*/
if(cores == 1) {
cib_max_cpu = 0.4;
}
if(throttle_load_target > 0.0 && throttle_load_target < cib_max_cpu) {
cib_max_cpu = throttle_load_target;
}
thresholds[0] = cib_max_cpu * 0.8;
thresholds[1] = cib_max_cpu * 0.9;
thresholds[2] = cib_max_cpu;
/* Can only happen on machines with a low number of cores */
thresholds[3] = cib_max_cpu * 1.5;
mode = throttle_check_thresholds(load, "CIB load", thresholds);
}
if(throttle_load_target <= 0) {
/* If we ever make this a valid value, the cluster will at least behave as expected */
return mode;
}
if(throttle_load_avg(&load)) {
enum throttle_state_e cpu_load;
cpu_load = throttle_handle_load(load, "CPU load", cores);
if (cpu_load > mode) {
mode = cpu_load;
}
crm_debug("Current load is %f across %u core(s)", load, cores);
}
#endif // SUPPORT_PROCFS
return mode;
}
static void
throttle_send_command(enum throttle_state_e mode)
{
xmlNode *xml = NULL;
static enum throttle_state_e last = -1;
if(mode != last) {
crm_info("New throttle mode: %s load (was %s)",
load2str(mode), load2str(last));
last = mode;
xml = create_request(CRM_OP_THROTTLE, NULL, NULL, CRM_SYSTEM_CRMD, CRM_SYSTEM_CRMD, NULL);
crm_xml_add_int(xml, F_CRM_THROTTLE_MODE, mode);
crm_xml_add_int(xml, F_CRM_THROTTLE_MAX, throttle_job_max);
send_cluster_message(NULL, crm_msg_crmd, xml, TRUE);
free_xml(xml);
}
}
static gboolean
throttle_timer_cb(gpointer data)
{
throttle_send_command(throttle_mode());
return TRUE;
}
static void
throttle_record_free(gpointer p)
{
struct throttle_record_s *r = p;
free(r->node);
free(r);
}
void
throttle_set_load_target(float target)
{
throttle_load_target = target;
}
void
throttle_update_job_max(const char *preference)
{
int max = 0;
throttle_job_max = 2 * crm_procfs_num_cores();
if(preference) {
/* Global preference from the CIB */
max = crm_int_helper(preference, NULL);
if(max > 0) {
throttle_job_max = max;
}
}
preference = getenv("PCMK_node_action_limit");
if(preference) {
/* Per-node override */
max = crm_int_helper(preference, NULL);
if(max > 0) {
throttle_job_max = max;
}
}
}
void
throttle_init(void)
{
if(throttle_records == NULL) {
throttle_records = g_hash_table_new_full(
crm_str_hash, g_str_equal, NULL, throttle_record_free);
throttle_timer = mainloop_timer_add("throttle", 30 * 1000, TRUE, throttle_timer_cb, NULL);
}
throttle_update_job_max(NULL);
mainloop_timer_start(throttle_timer);
}
void
throttle_fini(void)
{
if (throttle_timer != NULL) {
mainloop_timer_del(throttle_timer);
throttle_timer = NULL;
}
if (throttle_records != NULL) {
g_hash_table_destroy(throttle_records);
throttle_records = NULL;
}
}
int
throttle_get_total_job_limit(int l)
{
/* Cluster-wide limit */
GHashTableIter iter;
int limit = l;
int peers = crm_active_peers();
struct throttle_record_s *r = NULL;
g_hash_table_iter_init(&iter, throttle_records);
while (g_hash_table_iter_next(&iter, NULL, (gpointer *) &r)) {
switch(r->mode) {
case throttle_extreme:
if(limit == 0 || limit > peers/4) {
limit = QB_MAX(1, peers/4);
}
break;
case throttle_high:
if(limit == 0 || limit > peers/2) {
limit = QB_MAX(1, peers/2);
}
break;
default:
break;
}
}
if(limit == l) {
/* crm_trace("No change to batch-limit=%d", limit); */
} else if(l == 0) {
crm_trace("Using batch-limit=%d", limit);
} else {
crm_trace("Using batch-limit=%d instead of %d", limit, l);
}
return limit;
}
int
throttle_get_job_limit(const char *node)
{
int jobs = 1;
struct throttle_record_s *r = NULL;
r = g_hash_table_lookup(throttle_records, node);
if(r == NULL) {
r = calloc(1, sizeof(struct throttle_record_s));
r->node = strdup(node);
r->mode = throttle_low;
r->max = throttle_job_max;
crm_trace("Defaulting to local values for unknown node %s", node);
g_hash_table_insert(throttle_records, r->node, r);
}
switch(r->mode) {
case throttle_extreme:
case throttle_high:
jobs = 1; /* At least one job must always be allowed */
break;
case throttle_med:
jobs = QB_MAX(1, r->max / 4);
break;
case throttle_low:
jobs = QB_MAX(1, r->max / 2);
break;
case throttle_none:
jobs = QB_MAX(1, r->max);
break;
default:
crm_err("Unknown throttle mode %.4x on %s", r->mode, node);
break;
}
return jobs;
}
void
throttle_update(xmlNode *xml)
{
int max = 0;
int mode = 0;
struct throttle_record_s *r = NULL;
const char *from = crm_element_value(xml, F_CRM_HOST_FROM);
crm_element_value_int(xml, F_CRM_THROTTLE_MODE, &mode);
crm_element_value_int(xml, F_CRM_THROTTLE_MAX, &max);
r = g_hash_table_lookup(throttle_records, from);
if(r == NULL) {
r = calloc(1, sizeof(struct throttle_record_s));
r->node = strdup(from);
g_hash_table_insert(throttle_records, r->node, r);
}
r->max = max;
r->mode = (enum throttle_state_e) mode;
crm_debug("Node %s has %s load and supports at most %d jobs; new job limit %d",
from, load2str((enum throttle_state_e) mode), max,
throttle_get_job_limit(from));
}