loolwsd/LOOLBroker.cpp | 137 ++++++++++++++++++++++++++++++-------------------
1 file changed, 86 insertions(+), 51 deletions(-)
New commits:
commit cbabd6177d0e8aaaf77053d4ba17b069fc6dd4da
Author: Ashod Nakashian <ashod.nakash...@collabora.co.uk>
Date: Tue Mar 29 21:26:25 2016 -0400
loolwsd: improved child spawning and management
Spare child processes are now in a separate
container. A FIFO that gives older instances
priority to avoid using instances too young
to have initialized fully.
In addition, spare instances are now
proactively spawned such that there
is at least a minimum number of
spares at any given time.
Change-Id: Ibdb206d88473adb306c274f4af39798c784258a0
Reviewed-on: https://gerrit.libreoffice.org/23647
Reviewed-by: Ashod Nakashian <ashnak...@gmail.com>
Tested-by: Ashod Nakashian <ashnak...@gmail.com>
diff --git a/loolwsd/LOOLBroker.cpp b/loolwsd/LOOLBroker.cpp
index 49e2eef..49a9e1f 100644
--- a/loolwsd/LOOLBroker.cpp
+++ b/loolwsd/LOOLBroker.cpp
@@ -136,39 +136,32 @@ namespace
};
static std::map<Process::PID, std::shared_ptr<ChildProcess>>
_childProcesses;
+ static std::deque<std::shared_ptr<ChildProcess>> _newChildProcesses;
- /// Looks up a child hosting a URL, or returns an empty one.
+ /// Looks up a child hosting a URL, otherwise returns an empty one.
+ /// If neither exist, then returns null.
std::shared_ptr<ChildProcess> findChild(const std::string& url)
{
- std::shared_ptr<ChildProcess> child;
for (const auto& it : _childProcesses)
{
- Log::trace() << "Child [" << it.second->getPid()
- << "] url [" << url << "]." << Log::end;
if (it.second->getUrl() == url)
{
return it.second;
}
+ }
- if (it.second->getUrl().empty())
- {
- // Empty one, but keep going, we might find ours.
- child = it.second;
- }
+ // Try an empty one.
+ if (!_newChildProcesses.empty())
+ {
+ auto child = _newChildProcesses.front();
+ _newChildProcesses.pop_front();
+ return child;
}
- return child;
+ return nullptr;
}
- /// Looks up the pipe descriptor
- /// of a child. Returns -1 on error.
- int getChildPipe(const Process::PID pid)
- {
- const auto it = _childProcesses.find(pid);
- return (it != _childProcesses.end() ? it->second->getWritePipe() : -1);
- }
-
- /// Removes a child process.
+ /// Removes a used child process. New ones can't be removed.
void removeChild(const Process::PID pid, const bool rude)
{
const auto it = _childProcesses.find(pid);
@@ -189,24 +182,35 @@ public:
{
}
- bool createSession(const Process::PID pid, const std::string& session,
const std::string& url)
+ bool createSession(const std::shared_ptr<ChildProcess>& child, const
std::string& session, const std::string& url)
{
const std::string message = "session " + session + " " + url + "\n";
- if (IoUtil::writeFIFO(getChildPipe(pid), message) < 0)
+ const auto childPid = std::to_string(child->getPid());
+ const auto childPipe = child->getWritePipe();
+ if (IoUtil::writeFIFO(childPipe, message) < 0)
{
- Log::error("Error sending session message to child [" +
std::to_string(pid) + "].");
+ Log::error("Error sending session message to child [" + childPid +
"].");
return false;
}
- std::string response;
- if (_childPipeReader.readLine(response, [](){ return TerminationFlag;
}) < 0)
+ while (true)
{
- Log::error("Error reading response to session message from child
[" + std::to_string(pid) + "].");
- return false;
- }
+ std::string response;
+ if (_childPipeReader.readLine(response, [](){ return
TerminationFlag; }) <= 0)
+ {
+ Log::error("Error reading response to session message from
child [" + childPid + "].");
+ return false;
+ }
+
+ StringTokenizer tokens(response, " ",
StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
+ if (tokens.count() > 0 && tokens[0] != childPid)
+ {
+ // Not a response from the child in question.
+ continue;
+ }
- StringTokenizer tokens(response, " ",
StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);
- return (tokens.count() == 2 && tokens[0] == std::to_string(pid) &&
tokens[1] == "ok");
+ return (tokens.count() == 2 && tokens[1] == "ok");
+ }
}
/// Sync ChildProcess instances with its child.
@@ -294,19 +298,15 @@ public:
Log::debug("Found URL [" + url + "] hosted on child [" +
childPid + "].");
}
- if (createSession(child->getPid(), session, url))
+ if (createSession(child, session, url))
{
child->setUrl(url);
+ _childProcesses[child->getPid()] = child;
Log::debug("Child [" + childPid + "] now hosts [" + url +
"] for session [" + session + "].");
}
else
{
Log::error("Error creating session [" + session + "] for
URL [" + url + "] on child [" + childPid + "].");
- if (isEmptyChild)
- {
- // This is probably a child in bad state. Rid of it
and create new.
- removeChild(child->getPid(), true);
- }
}
}
else
@@ -520,7 +520,7 @@ static int createLibreOfficeKit(const bool sharePages,
Log::info() << "Adding Kit #" << childCounter << ", PID: " << childPID <<
Log::end;
- _childProcesses[childPID] = std::make_shared<ChildProcess>(childPID, -1,
fifoWriter);
+ _newChildProcesses.emplace_back(std::make_shared<ChildProcess>(childPID,
-1, fifoWriter));
return childPID;
}
@@ -751,7 +751,7 @@ int main(int argc, char** argv)
Util::removeFile(childPath, true);
}
- pipeHandler.syncChildren();
+ //pipeHandler.syncChildren();
timeoutCounter = 0;
}
else if (pid < 0)
@@ -781,24 +781,43 @@ int main(int argc, char** argv)
{
std::lock_guard<std::mutex> lock(forkMutex);
- const int empty = pipeHandler.syncChildren();
- const int total = _childProcesses.size();
+ const auto childCount = _childProcesses.size();
+ const int newChildCount = _newChildProcesses.size();
// Figure out how many children we need. Always create at least as
many
// as configured pre-spawn or one more than requested (whichever
is larger).
int spawn = std::max(static_cast<int>(forkCounter) + 1,
numPreSpawnedChildren);
- Log::debug() << "Creating " << spawn << (spawn == 1 ? " child" : "
children") << ". Current total: "
- << total << ", Empty: " << empty << Log::end;
- do
+ if (spawn > newChildCount)
{
- if (createLibreOfficeKit(sharePages, childRoot, sysTemplate,
- loTemplate, loSubPath) < 0)
- Log::error("Error: fork failed.");
- }
- while (--spawn > 0);
+ spawn -= newChildCount;
+ Log::info() << "Creating " << spawn << " new child. Current
total: "
+ << childCount << " + " << newChildCount << " (new)
= "
+ << (childCount + newChildCount) << "." << Log::end;
+ size_t newInstances = 0;
+ do
+ {
+ if (createLibreOfficeKit(sharePages, childRoot,
sysTemplate,
+ loTemplate, loSubPath) < 0)
+ {
+ Log::error("Error: fork failed.");
+ }
+ else
+ {
+ ++newInstances;
+ }
+ }
+ while (--spawn > 0);
- // We've done our best. If need more, retrying will bump the
counter.
- forkCounter = 0;
+ // We've done our best. If need more, retrying will bump the
counter.
+ forkCounter = (newInstances > forkCounter ? 0 : forkCounter -
newInstances);
+ }
+ else
+ {
+ Log::info() << "Requested " << spawn << " new child. Current
total: "
+ << childCount << " + " << newChildCount << " (new)
= "
+ << (childCount + newChildCount) << ". Will not
spawn yet." << Log::end;
+ forkCounter = 0;
+ }
}
if (timeoutCounter++ == INTERVAL_PROBES)
@@ -809,14 +828,20 @@ int main(int argc, char** argv)
}
}
- // Terminate child processes
+ // Terminate child processes.
for (auto& it : _childProcesses)
{
Log::info("Requesting child process " + std::to_string(it.first) + "
to terminate.");
Util::requestTermination(it.first);
}
- // Wait and kill child processes
+ for (auto& it : _newChildProcesses)
+ {
+ Log::info("Requesting child process " + std::to_string(it->getPid()) +
" to terminate.");
+ Util::requestTermination(it->getPid());
+ }
+
+ // Wait and kill child processes.
for (auto& it : _childProcesses)
{
if (!waitForTerminationChild(it.first))
@@ -826,7 +851,17 @@ int main(int argc, char** argv)
}
}
+ for (auto& it : _newChildProcesses)
+ {
+ if (!waitForTerminationChild(it->getPid()))
+ {
+ Log::info("Forcing child process " + std::to_string(it->getPid())
+ " to terminate.");
+ Process::kill(it->getPid());
+ }
+ }
+
_childProcesses.clear();
+ _newChildProcesses.clear();
pipeThread.join();
close(writerNotify);
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