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MDBalancer.cc
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MDBalancer.cc
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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include "include/compat.h"
#include "mdstypes.h"
#include "mon/MonClient.h"
#include "MDBalancer.h"
#include "MDSRank.h"
#include "MDSMap.h"
#include "CInode.h"
#include "CDir.h"
#include "MDCache.h"
#include "Migrator.h"
#include "Mantle.h"
#include "include/Context.h"
#include "msg/Messenger.h"
#include <fstream>
#include <iostream>
#include <vector>
#include <map>
using std::map;
using std::vector;
using std::chrono::duration_cast;
#include "common/config.h"
#include "common/errno.h"
#define dout_context g_ceph_context
#undef dout_prefix
#define dout_prefix *_dout << "mds." << mds->get_nodeid() << ".bal "
#undef dout
#define dout(lvl) \
do {\
auto subsys = ceph_subsys_mds;\
if ((dout_context)->_conf->subsys.should_gather(ceph_subsys_mds_balancer, lvl)) {\
subsys = ceph_subsys_mds_balancer;\
}\
dout_impl(dout_context, ceph::dout::need_dynamic(subsys), lvl) dout_prefix
#undef dendl
#define dendl dendl_impl; } while (0)
#define MIN_LOAD 50 // ??
#define MIN_REEXPORT 5 // will automatically reexport
#define MIN_OFFLOAD 10 // point at which i stop trying, close enough
int MDBalancer::proc_message(const Message::const_ref &m)
{
switch (m->get_type()) {
case MSG_MDS_HEARTBEAT:
handle_heartbeat(MHeartbeat::msgref_cast(m));
break;
default:
derr << " balancer unknown message " << m->get_type() << dendl_impl;
ceph_abort_msg("balancer unknown message");
}
return 0;
}
MDBalancer::MDBalancer(MDSRank *m, Messenger *msgr, MonClient *monc) :
mds(m), messenger(msgr), mon_client(monc)
{
bal_fragment_dirs = g_conf().get_val<bool>("mds_bal_fragment_dirs");
bal_fragment_interval = g_conf().get_val<int64_t>("mds_bal_fragment_interval");
}
void MDBalancer::handle_conf_change(const std::set<std::string>& changed, const MDSMap& mds_map)
{
if (changed.count("mds_bal_fragment_dirs"))
bal_fragment_dirs = g_conf().get_val<bool>("mds_bal_fragment_dirs");
if (changed.count("mds_bal_fragment_interval"))
bal_fragment_interval = g_conf().get_val<int64_t>("mds_bal_fragment_interval");
}
void MDBalancer::handle_export_pins(void)
{
auto &q = mds->mdcache->export_pin_queue;
auto it = q.begin();
dout(20) << "export_pin_queue size=" << q.size() << dendl;
while (it != q.end()) {
auto cur = it++;
CInode *in = *cur;
ceph_assert(in->is_dir());
mds_rank_t export_pin = in->get_export_pin(false);
if (export_pin >= mds->mdsmap->get_max_mds()) {
dout(20) << " delay export pin on " << *in << dendl;
in->state_clear(CInode::STATE_QUEUEDEXPORTPIN);
q.erase(cur);
in->state_set(CInode::STATE_DELAYEDEXPORTPIN);
mds->mdcache->export_pin_delayed_queue.insert(in);
continue;
}
bool remove = true;
list<CDir*> dfls;
in->get_dirfrags(dfls);
for (auto dir : dfls) {
if (!dir->is_auth())
continue;
if (export_pin == MDS_RANK_NONE) {
if (dir->state_test(CDir::STATE_AUXSUBTREE)) {
if (dir->is_frozen() || dir->is_freezing()) {
// try again later
remove = false;
continue;
}
dout(10) << " clear auxsubtree on " << *dir << dendl;
dir->state_clear(CDir::STATE_AUXSUBTREE);
mds->mdcache->try_subtree_merge(dir);
}
} else if (export_pin == mds->get_nodeid()) {
if (dir->state_test(CDir::STATE_CREATING) ||
dir->is_frozen() || dir->is_freezing()) {
// try again later
remove = false;
continue;
}
if (!dir->is_subtree_root()) {
dir->state_set(CDir::STATE_AUXSUBTREE);
mds->mdcache->adjust_subtree_auth(dir, mds->get_nodeid());
dout(10) << " create aux subtree on " << *dir << dendl;
} else if (!dir->state_test(CDir::STATE_AUXSUBTREE)) {
dout(10) << " set auxsubtree bit on " << *dir << dendl;
dir->state_set(CDir::STATE_AUXSUBTREE);
}
} else {
mds->mdcache->migrator->export_dir(dir, export_pin);
remove = false;
}
}
if (remove) {
in->state_clear(CInode::STATE_QUEUEDEXPORTPIN);
q.erase(cur);
}
}
std::vector<CDir *> authsubs = mds->mdcache->get_auth_subtrees();
bool print_auth_subtrees = true;
if (authsubs.size() > AUTH_TREES_THRESHOLD &&
!g_conf()->subsys.should_gather<ceph_subsys_mds, 25>()) {
dout(15) << "number of auth trees = " << authsubs.size() << "; not "
"printing auth trees" << dendl;
print_auth_subtrees = false;
}
for (auto &cd : authsubs) {
mds_rank_t export_pin = cd->inode->get_export_pin();
if (print_auth_subtrees) {
dout(25) << "auth tree " << *cd << " export_pin=" << export_pin <<
dendl;
}
if (export_pin >= 0 && export_pin < mds->mdsmap->get_max_mds()
&& export_pin != mds->get_nodeid()) {
mds->mdcache->migrator->export_dir(cd, export_pin);
}
}
}
void MDBalancer::tick()
{
static int num_bal_times = g_conf()->mds_bal_max;
auto bal_interval = g_conf().get_val<int64_t>("mds_bal_interval");
auto bal_max_until = g_conf().get_val<int64_t>("mds_bal_max_until");
time now = clock::now();
if (g_conf()->mds_bal_export_pin) {
handle_export_pins();
}
// sample?
if (chrono::duration<double>(now-last_sample).count() >
g_conf()->mds_bal_sample_interval) {
dout(15) << "tick last_sample now " << now << dendl;
last_sample = now;
}
// We can use duration_cast below, although the result is an int,
// because the values from g_conf are also integers.
// balance?
if (mds->get_nodeid() == 0
&& mds->is_active()
&& bal_interval > 0
&& duration_cast<chrono::seconds>(now - last_heartbeat).count() >= bal_interval
&& (num_bal_times || (bal_max_until >= 0 && mds->get_uptime().count() > bal_max_until))) {
last_heartbeat = now;
send_heartbeat();
num_bal_times--;
}
mds->mdcache->show_subtrees(10, true);
}
class C_Bal_SendHeartbeat : public MDSInternalContext {
public:
explicit C_Bal_SendHeartbeat(MDSRank *mds_) : MDSInternalContext(mds_) { }
void finish(int f) override {
mds->balancer->send_heartbeat();
}
};
double mds_load_t::mds_load() const
{
switch(g_conf()->mds_bal_mode) {
case 0:
return
.8 * auth.meta_load() +
.2 * all.meta_load() +
req_rate +
10.0 * queue_len;
case 1:
return req_rate + 10.0*queue_len;
case 2:
return cpu_load_avg;
}
ceph_abort();
return 0;
}
mds_load_t MDBalancer::get_load()
{
auto now = clock::now();
mds_load_t load{DecayRate()}; /* zero DecayRate! */
if (mds->mdcache->get_root()) {
list<CDir*> ls;
mds->mdcache->get_root()->get_dirfrags(ls);
for (auto &d : ls) {
load.auth.add(d->pop_auth_subtree_nested);
load.all.add(d->pop_nested);
}
} else {
dout(20) << "get_load no root, no load" << dendl;
}
uint64_t num_requests = mds->get_num_requests();
uint64_t cpu_time = 1;
{
string stat_path = PROCPREFIX "/proc/self/stat";
ifstream stat_file(stat_path);
if (stat_file.is_open()) {
vector<string> stat_vec(std::istream_iterator<string>{stat_file},
std::istream_iterator<string>());
if (stat_vec.size() >= 15) {
// utime + stime
cpu_time = strtoll(stat_vec[13].c_str(), nullptr, 10) +
strtoll(stat_vec[14].c_str(), nullptr, 10);
} else {
derr << "input file '" << stat_path << "' not resolvable" << dendl_impl;
}
} else {
derr << "input file '" << stat_path << "' not found" << dendl_impl;
}
}
load.queue_len = messenger->get_dispatch_queue_len();
bool update_last = true;
if (last_get_load != clock::zero() &&
now > last_get_load) {
double el = std::chrono::duration<double>(now-last_get_load).count();
if (el >= 1.0) {
if (num_requests > last_num_requests)
load.req_rate = (num_requests - last_num_requests) / el;
if (cpu_time > last_cpu_time)
load.cpu_load_avg = (cpu_time - last_cpu_time) / el;
} else {
auto p = mds_load.find(mds->get_nodeid());
if (p != mds_load.end()) {
load.req_rate = p->second.req_rate;
load.cpu_load_avg = p->second.cpu_load_avg;
}
if (num_requests >= last_num_requests && cpu_time >= last_cpu_time)
update_last = false;
}
}
if (update_last) {
last_num_requests = num_requests;
last_cpu_time = cpu_time;
last_get_load = now;
}
dout(15) << "get_load " << load << dendl;
return load;
}
/*
* Read synchronously from RADOS using a timeout. We cannot do daemon-local
* fallbacks (i.e. kick off async read when we are processing the map and
* check status when we get here) with the way the mds is structured.
*/
int MDBalancer::localize_balancer()
{
/* reset everything */
bool ack = false;
int r = 0;
bufferlist lua_src;
Mutex lock("lock");
Cond cond;
/* we assume that balancer is in the metadata pool */
object_t oid = object_t(mds->mdsmap->get_balancer());
object_locator_t oloc(mds->mdsmap->get_metadata_pool());
ceph_tid_t tid = mds->objecter->read(oid, oloc, 0, 0, CEPH_NOSNAP, &lua_src, 0,
new C_SafeCond(&lock, &cond, &ack, &r));
dout(15) << "launched non-blocking read tid=" << tid
<< " oid=" << oid << " oloc=" << oloc << dendl;
/* timeout: if we waste half our time waiting for RADOS, then abort! */
auto bal_interval = g_conf().get_val<int64_t>("mds_bal_interval");
lock.Lock();
int ret_t = cond.WaitInterval(lock, utime_t(bal_interval / 2, 0));
lock.Unlock();
/* success: store the balancer in memory and set the version. */
if (!r) {
if (ret_t == ETIMEDOUT) {
mds->objecter->op_cancel(tid, -ECANCELED);
return -ETIMEDOUT;
}
bal_code.assign(lua_src.to_str());
bal_version.assign(oid.name);
dout(10) << "localized balancer, bal_code=" << bal_code << dendl;
}
return r;
}
void MDBalancer::send_heartbeat()
{
if (mds->is_cluster_degraded()) {
dout(10) << "send_heartbeat degraded" << dendl;
return;
}
if (!mds->mdcache->is_open()) {
dout(5) << "not open" << dendl;
mds->mdcache->wait_for_open(new C_Bal_SendHeartbeat(mds));
return;
}
if (mds->get_nodeid() == 0) {
beat_epoch++;
mds_load.clear();
}
// my load
mds_load_t load = get_load();
mds->logger->set(l_mds_load_cent, 100 * load.mds_load());
mds->logger->set(l_mds_dispatch_queue_len, load.queue_len);
auto em = mds_load.emplace(std::piecewise_construct, std::forward_as_tuple(mds->get_nodeid()), std::forward_as_tuple(load));
if (!em.second) {
em.first->second = load;
}
// import_map -- how much do i import from whom
map<mds_rank_t, float> import_map;
for (auto& im : mds->mdcache->get_auth_subtrees()) {
mds_rank_t from = im->inode->authority().first;
if (from == mds->get_nodeid()) continue;
if (im->get_inode()->is_stray()) continue;
import_map[from] += im->pop_auth_subtree.meta_load();
}
mds_import_map[ mds->get_nodeid() ] = import_map;
dout(5) << "mds." << mds->get_nodeid() << " epoch " << beat_epoch << " load " << load << dendl;
for (map<mds_rank_t, float>::iterator it = import_map.begin();
it != import_map.end();
++it) {
dout(5) << " import_map from " << it->first << " -> " << it->second << dendl;
}
set<mds_rank_t> up;
mds->get_mds_map()->get_up_mds_set(up);
for (const auto& r : up) {
if (r == mds->get_nodeid())
continue;
auto hb = MHeartbeat::create(load, beat_epoch);
hb->get_import_map() = import_map;
mds->send_message_mds(hb, r);
}
}
void MDBalancer::handle_heartbeat(const MHeartbeat::const_ref &m)
{
mds_rank_t who = mds_rank_t(m->get_source().num());
dout(25) << "=== got heartbeat " << m->get_beat() << " from " << m->get_source().num() << " " << m->get_load() << dendl;
if (!mds->is_active())
return;
if (!mds->mdcache->is_open()) {
dout(10) << "opening root on handle_heartbeat" << dendl;
mds->mdcache->wait_for_open(new C_MDS_RetryMessage(mds, m));
return;
}
if (mds->is_cluster_degraded()) {
dout(10) << " degraded, ignoring" << dendl;
return;
}
if (mds->get_nodeid() != 0 && m->get_beat() > beat_epoch) {
dout(10) << "receive next epoch " << m->get_beat() << " from mds." << who << " before mds0" << dendl;
beat_epoch = m->get_beat();
// clear the mds load info whose epoch is less than beat_epoch
mds_load.clear();
}
if (who == 0) {
dout(20) << " from mds0, new epoch " << m->get_beat() << dendl;
if (beat_epoch != m->get_beat()) {
beat_epoch = m->get_beat();
mds_load.clear();
}
send_heartbeat();
mds->mdcache->show_subtrees();
} else if (mds->get_nodeid() == 0) {
if (beat_epoch != m->get_beat()) {
dout(10) << " old heartbeat epoch, ignoring" << dendl;
return;
}
}
{
auto em = mds_load.emplace(std::piecewise_construct, std::forward_as_tuple(who), std::forward_as_tuple(m->get_load()));
if (!em.second) {
em.first->second = m->get_load();
}
}
mds_import_map[who] = m->get_import_map();
{
unsigned cluster_size = mds->get_mds_map()->get_num_in_mds();
if (mds_load.size() == cluster_size) {
// let's go!
//export_empties(); // no!
/* avoid spamming ceph -w if user does not turn mantle on */
if (mds->mdsmap->get_balancer() != "") {
int r = mantle_prep_rebalance();
if (!r) return;
mds->clog->warn() << "using old balancer; mantle failed for "
<< "balancer=" << mds->mdsmap->get_balancer()
<< " : " << cpp_strerror(r);
}
prep_rebalance(m->get_beat());
}
}
}
double MDBalancer::try_match(balance_state_t& state, mds_rank_t ex, double& maxex,
mds_rank_t im, double& maxim)
{
if (maxex <= 0 || maxim <= 0) return 0.0;
double howmuch = std::min(maxex, maxim);
if (howmuch <= 0) return 0.0;
dout(5) << " - mds." << ex << " exports " << howmuch << " to mds." << im << dendl;
if (ex == mds->get_nodeid())
state.targets[im] += howmuch;
state.exported[ex] += howmuch;
state.imported[im] += howmuch;
maxex -= howmuch;
maxim -= howmuch;
return howmuch;
}
void MDBalancer::queue_split(const CDir *dir, bool fast)
{
dout(10) << __func__ << " enqueuing " << *dir
<< " (fast=" << fast << ")" << dendl;
const dirfrag_t frag = dir->dirfrag();
auto callback = [this, frag](int r) {
if (split_pending.erase(frag) == 0) {
// Someone beat me to it. This can happen in the fast splitting
// path, because we spawn two contexts, one with mds->timer and
// one with mds->queue_waiter. The loser can safely just drop
// out.
return;
}
CDir *split_dir = mds->mdcache->get_dirfrag(frag);
if (!split_dir) {
dout(10) << "drop split on " << frag << " because not in cache" << dendl;
return;
}
if (!split_dir->is_auth()) {
dout(10) << "drop split on " << frag << " because non-auth" << dendl;
return;
}
// Pass on to MDCache: note that the split might still not
// happen if the checks in MDCache::can_fragment fail.
dout(10) << __func__ << " splitting " << *split_dir << dendl;
mds->mdcache->split_dir(split_dir, g_conf()->mds_bal_split_bits);
};
bool is_new = false;
if (split_pending.count(frag) == 0) {
split_pending.insert(frag);
is_new = true;
}
if (fast) {
// Do the split ASAP: enqueue it in the MDSRank waiters which are
// run at the end of dispatching the current request
mds->queue_waiter(new MDSInternalContextWrapper(mds,
new FunctionContext(callback)));
} else if (is_new) {
// Set a timer to really do the split: we don't do it immediately
// so that bursts of ops on a directory have a chance to go through
// before we freeze it.
mds->timer.add_event_after(bal_fragment_interval,
new FunctionContext(callback));
}
}
void MDBalancer::queue_merge(CDir *dir)
{
const auto frag = dir->dirfrag();
auto callback = [this, frag](int r) {
ceph_assert(frag.frag != frag_t());
// frag must be in this set because only one context is in flight
// for a given frag at a time (because merge_pending is checked before
// starting one), and this context is the only one that erases it.
merge_pending.erase(frag);
CDir *dir = mds->mdcache->get_dirfrag(frag);
if (!dir) {
dout(10) << "drop merge on " << frag << " because not in cache" << dendl;
return;
}
ceph_assert(dir->dirfrag() == frag);
if(!dir->is_auth()) {
dout(10) << "drop merge on " << *dir << " because lost auth" << dendl;
return;
}
dout(10) << "merging " << *dir << dendl;
CInode *diri = dir->get_inode();
frag_t fg = dir->get_frag();
while (fg != frag_t()) {
frag_t sibfg = fg.get_sibling();
list<CDir*> sibs;
bool complete = diri->get_dirfrags_under(sibfg, sibs);
if (!complete) {
dout(10) << " not all sibs under " << sibfg << " in cache (have " << sibs << ")" << dendl;
break;
}
bool all = true;
for (list<CDir*>::iterator p = sibs.begin(); p != sibs.end(); ++p) {
CDir *sib = *p;
if (!sib->is_auth() || !sib->should_merge()) {
all = false;
break;
}
}
if (!all) {
dout(10) << " not all sibs under " << sibfg << " " << sibs << " should_merge" << dendl;
break;
}
dout(10) << " all sibs under " << sibfg << " " << sibs << " should merge" << dendl;
fg = fg.parent();
}
if (fg != dir->get_frag())
mds->mdcache->merge_dir(diri, fg);
};
if (merge_pending.count(frag) == 0) {
dout(20) << __func__ << " enqueued dir " << *dir << dendl;
merge_pending.insert(frag);
mds->timer.add_event_after(bal_fragment_interval,
new FunctionContext(callback));
} else {
dout(20) << __func__ << " dir already in queue " << *dir << dendl;
}
}
void MDBalancer::prep_rebalance(int beat)
{
balance_state_t state;
if (g_conf()->mds_thrash_exports) {
//we're going to randomly export to all the mds in the cluster
set<mds_rank_t> up_mds;
mds->get_mds_map()->get_up_mds_set(up_mds);
for (const auto &rank : up_mds) {
state.targets[rank] = 0.0;
}
} else {
int cluster_size = mds->get_mds_map()->get_num_in_mds();
mds_rank_t whoami = mds->get_nodeid();
rebalance_time = clock::now();
dout(5) << " prep_rebalance: cluster loads are" << dendl;
mds->mdcache->migrator->clear_export_queue();
// rescale! turn my mds_load back into meta_load units
double load_fac = 1.0;
map<mds_rank_t, mds_load_t>::iterator m = mds_load.find(whoami);
if ((m != mds_load.end()) && (m->second.mds_load() > 0)) {
double metald = m->second.auth.meta_load();
double mdsld = m->second.mds_load();
load_fac = metald / mdsld;
dout(7) << " load_fac is " << load_fac
<< " <- " << m->second.auth << " " << metald
<< " / " << mdsld
<< dendl;
}
mds_meta_load.clear();
double total_load = 0.0;
multimap<double,mds_rank_t> load_map;
for (mds_rank_t i=mds_rank_t(0); i < mds_rank_t(cluster_size); i++) {
mds_load_t& load = mds_load.at(i);
double l = load.mds_load() * load_fac;
mds_meta_load[i] = l;
if (whoami == 0)
dout(5) << " mds." << i
<< " " << load
<< " = " << load.mds_load()
<< " ~ " << l << dendl;
if (whoami == i) my_load = l;
total_load += l;
load_map.insert(pair<double,mds_rank_t>( l, i ));
}
// target load
target_load = total_load / (double)cluster_size;
dout(5) << "prep_rebalance: my load " << my_load
<< " target " << target_load
<< " total " << total_load
<< dendl;
// under or over?
for (auto p : load_map) {
if (p.first < target_load * (1.0 + g_conf()->mds_bal_min_rebalance)) {
dout(5) << " mds." << p.second << " is underloaded or barely overloaded." << dendl;
mds_last_epoch_under_map[p.second] = beat_epoch;
}
}
int last_epoch_under = mds_last_epoch_under_map[whoami];
if (last_epoch_under == beat_epoch) {
dout(5) << " i am underloaded or barely overloaded, doing nothing." << dendl;
return;
}
// am i over long enough?
if (last_epoch_under && beat_epoch - last_epoch_under < 2) {
dout(5) << " i am overloaded, but only for " << (beat_epoch - last_epoch_under) << " epochs" << dendl;
return;
}
dout(5) << " i am sufficiently overloaded" << dendl;
// first separate exporters and importers
multimap<double,mds_rank_t> importers;
multimap<double,mds_rank_t> exporters;
set<mds_rank_t> importer_set;
set<mds_rank_t> exporter_set;
for (multimap<double,mds_rank_t>::iterator it = load_map.begin();
it != load_map.end();
++it) {
if (it->first < target_load) {
dout(15) << " mds." << it->second << " is importer" << dendl;
importers.insert(pair<double,mds_rank_t>(it->first,it->second));
importer_set.insert(it->second);
} else {
int mds_last_epoch_under = mds_last_epoch_under_map[it->second];
if (!(mds_last_epoch_under && beat_epoch - mds_last_epoch_under < 2)) {
dout(15) << " mds." << it->second << " is exporter" << dendl;
exporters.insert(pair<double,mds_rank_t>(it->first,it->second));
exporter_set.insert(it->second);
}
}
}
// determine load transfer mapping
if (true) {
// analyze import_map; do any matches i can
dout(15) << " matching exporters to import sources" << dendl;
// big -> small exporters
for (multimap<double,mds_rank_t>::reverse_iterator ex = exporters.rbegin();
ex != exporters.rend();
++ex) {
double maxex = get_maxex(state, ex->second);
if (maxex <= .001) continue;
// check importers. for now, just in arbitrary order (no intelligent matching).
for (map<mds_rank_t, float>::iterator im = mds_import_map[ex->second].begin();
im != mds_import_map[ex->second].end();
++im) {
double maxim = get_maxim(state, im->first);
if (maxim <= .001) continue;
try_match(state, ex->second, maxex, im->first, maxim);
if (maxex <= .001) break;
}
}
}
// old way
if (beat % 2 == 1) {
dout(15) << " matching big exporters to big importers" << dendl;
// big exporters to big importers
multimap<double,mds_rank_t>::reverse_iterator ex = exporters.rbegin();
multimap<double,mds_rank_t>::iterator im = importers.begin();
while (ex != exporters.rend() &&
im != importers.end()) {
double maxex = get_maxex(state, ex->second);
double maxim = get_maxim(state, im->second);
if (maxex < .001 || maxim < .001) break;
try_match(state, ex->second, maxex, im->second, maxim);
if (maxex <= .001) ++ex;
if (maxim <= .001) ++im;
}
} else { // new way
dout(15) << " matching small exporters to big importers" << dendl;
// small exporters to big importers
multimap<double,mds_rank_t>::iterator ex = exporters.begin();
multimap<double,mds_rank_t>::iterator im = importers.begin();
while (ex != exporters.end() &&
im != importers.end()) {
double maxex = get_maxex(state, ex->second);
double maxim = get_maxim(state, im->second);
if (maxex < .001 || maxim < .001) break;
try_match(state, ex->second, maxex, im->second, maxim);
if (maxex <= .001) ++ex;
if (maxim <= .001) ++im;
}
}
}
try_rebalance(state);
}
int MDBalancer::mantle_prep_rebalance()
{
balance_state_t state;
/* refresh balancer if it has changed */
if (bal_version != mds->mdsmap->get_balancer()) {
bal_version.assign("");
int r = localize_balancer();
if (r) return r;
/* only spam the cluster log from 1 mds on version changes */
if (mds->get_nodeid() == 0)
mds->clog->info() << "mantle balancer version changed: " << bal_version;
}
/* prepare for balancing */
int cluster_size = mds->get_mds_map()->get_num_in_mds();
rebalance_time = clock::now();
mds->mdcache->migrator->clear_export_queue();
/* fill in the metrics for each mds by grabbing load struct */
vector < map<string, double> > metrics (cluster_size);
for (mds_rank_t i=mds_rank_t(0); i < mds_rank_t(cluster_size); i++) {
mds_load_t& load = mds_load.at(i);
metrics[i] = {{"auth.meta_load", load.auth.meta_load()},
{"all.meta_load", load.all.meta_load()},
{"req_rate", load.req_rate},
{"queue_len", load.queue_len},
{"cpu_load_avg", load.cpu_load_avg}};
}
/* execute the balancer */
Mantle mantle;
int ret = mantle.balance(bal_code, mds->get_nodeid(), metrics, state.targets);
dout(5) << " mantle decided that new targets=" << state.targets << dendl;
/* mantle doesn't know about cluster size, so check target len here */
if ((int) state.targets.size() != cluster_size)
return -EINVAL;
else if (ret)
return ret;
try_rebalance(state);
return 0;
}
void MDBalancer::try_rebalance(balance_state_t& state)
{
if (g_conf()->mds_thrash_exports) {
dout(5) << "mds_thrash is on; not performing standard rebalance operation!"
<< dendl;
return;
}
// make a sorted list of my imports
multimap<double, CDir*> import_pop_map;
multimap<mds_rank_t, pair<CDir*, double> > import_from_map;
for (auto& dir : mds->mdcache->get_fullauth_subtrees()) {
CInode *diri = dir->get_inode();
if (diri->is_mdsdir())
continue;
if (diri->get_export_pin(false) != MDS_RANK_NONE)
continue;
if (dir->is_freezing() || dir->is_frozen())
continue; // export pbly already in progress
mds_rank_t from = diri->authority().first;
double pop = dir->pop_auth_subtree.meta_load();
if (g_conf()->mds_bal_idle_threshold > 0 &&
pop < g_conf()->mds_bal_idle_threshold &&
diri != mds->mdcache->get_root() &&
from != mds->get_nodeid()) {
dout(5) << " exporting idle (" << pop << ") import " << *dir
<< " back to mds." << from << dendl;
mds->mdcache->migrator->export_dir_nicely(dir, from);
continue;
}
dout(15) << " map: i imported " << *dir << " from " << from << dendl;
import_pop_map.insert(make_pair(pop, dir));
import_from_map.insert(make_pair(from, make_pair(dir, pop)));
}
// do my exports!
map<mds_rank_t, double> export_pop_map;
for (auto &it : state.targets) {
mds_rank_t target = it.first;
double amount = it.second;
if (amount < MIN_OFFLOAD)
continue;
if (amount * 10 * state.targets.size() < target_load)
continue;
dout(5) << "want to send " << amount << " to mds." << target
//<< " .. " << (*it).second << " * " << load_fac
<< " -> " << amount
<< dendl;//" .. fudge is " << fudge << dendl;
double& have = export_pop_map[target];
mds->mdcache->show_subtrees();
// search imports from target
if (import_from_map.count(target)) {
dout(5) << " aha, looking through imports from target mds." << target << dendl;
for (auto p = import_from_map.equal_range(target);
p.first != p.second; ) {
CDir *dir = p.first->second.first;
double pop = p.first->second.second;
dout(5) << "considering " << *dir << " from " << (*p.first).first << dendl;
auto plast = p.first++;
if (dir->inode->is_base())
continue;
ceph_assert(dir->inode->authority().first == target); // cuz that's how i put it in the map, dummy
if (pop <= amount-have) {
dout(5) << "reexporting " << *dir << " pop " << pop
<< " back to mds." << target << dendl;
mds->mdcache->migrator->export_dir_nicely(dir, target);
have += pop;
import_from_map.erase(plast);
for (auto q = import_pop_map.equal_range(pop);
q.first != q.second; ) {
if (q.first->second == dir) {
import_pop_map.erase(q.first);
break;
}
q.first++;
}
} else {
dout(5) << "can't reexport " << *dir << ", too big " << pop << dendl;
}
if (amount-have < MIN_OFFLOAD)
break;
}
}
}
// any other imports
for (auto &it : state.targets) {
mds_rank_t target = it.first;
double amount = it.second;
if (!export_pop_map.count(target))
continue;
double& have = export_pop_map[target];
if (amount-have < MIN_OFFLOAD)
continue;
for (auto p = import_pop_map.begin();
p != import_pop_map.end(); ) {
CDir *dir = p->second;
if (dir->inode->is_base()) {
++p;
continue;
}
double pop = p->first;
if (pop <= amount-have && pop > MIN_REEXPORT) {
dout(0) << "reexporting " << *dir << " pop " << pop
<< " to mds." << target << dendl;
have += pop;
mds->mdcache->migrator->export_dir_nicely(dir, target);
import_pop_map.erase(p++);
} else {
++p;
}
if (amount-have < MIN_OFFLOAD)
break;
}
}
set<CDir*> already_exporting;
for (auto &it : state.targets) {
mds_rank_t target = it.first;
double amount = it.second;
if (!export_pop_map.count(target))
continue;
double& have = export_pop_map[target];
if (amount-have < MIN_OFFLOAD)
continue;
// okay, search for fragments of my workload
list<CDir*> exports;
for (auto p = import_pop_map.rbegin();
p != import_pop_map.rend();
++p) {
CDir *dir = p->second;
find_exports(dir, amount, exports, have, already_exporting);
if (amount-have < MIN_OFFLOAD)
break;
}
//fudge = amount - have;