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Problem: huge stack allocation in Windows select code

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Solution: use fast_vector_t as in poll implementation
This commit is contained in:
Simon Giesecke 2018-06-01 11:45:21 +02:00
parent 2533ffed86
commit 7c0efcb588
1 changed files with 51 additions and 19 deletions
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70
src/zmq.cpp
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@ -853,6 +853,31 @@ static size_t valid_pollset_bytes (const fd_set &pollset_)
return sizeof (fd_set);
#endif
}
#if defined ZMQ_HAVE_WINDOWS
class optimized_fd_set_t
{
public:
optimized_fd_set_t (size_t nevents_) : _fd_set (nevents_) {}
fd_set *get () { return reinterpret_cast<fd_set *> (&_fd_set[0]); }
private:
fast_vector_t<char, sizeof (u_int) + ZMQ_POLLITEMS_DFLT * sizeof (SOCKET)>
_fd_set;
};
#else
class optimized_fd_set_t
{
public:
optimized_fd_set_t (size_t /*nevents_*/) {}
fd_set *get () { return &_fd_set; }
private:
fd_set _fd_set;
};
#endif
#endif
#endif
@ -924,12 +949,12 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// TODO since this function is called by a client, we could return errno EINVAL/ENOMEM/... here
zmq_assert (nitems_ <= FD_SETSIZE);
fd_set pollset_in;
FD_ZERO (&pollset_in);
fd_set pollset_out;
FD_ZERO (&pollset_out);
fd_set pollset_err;
FD_ZERO (&pollset_err);
optimized_fd_set_t pollset_in (nitems_);
FD_ZERO (pollset_in.get ());
optimized_fd_set_t pollset_out (nitems_);
FD_ZERO (pollset_out.get ());
optimized_fd_set_t pollset_err (nitems_);
FD_ZERO (pollset_err.get ());
zmq::fd_t maxfd = 0;
@ -945,7 +970,7 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
== -1)
return -1;
if (items_[i].events) {
FD_SET (notify_fd, &pollset_in);
FD_SET (notify_fd, pollset_in.get ());
if (maxfd < notify_fd)
maxfd = notify_fd;
}
@ -954,17 +979,19 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// events to the appropriate fd_sets.
else {
if (items_[i].events & ZMQ_POLLIN)
FD_SET (items_[i].fd, &pollset_in);
FD_SET (items_[i].fd, pollset_in.get ());
if (items_[i].events & ZMQ_POLLOUT)
FD_SET (items_[i].fd, &pollset_out);
FD_SET (items_[i].fd, pollset_out.get ());
if (items_[i].events & ZMQ_POLLERR)
FD_SET (items_[i].fd, &pollset_err);
FD_SET (items_[i].fd, pollset_err.get ());
if (maxfd < items_[i].fd)
maxfd = items_[i].fd;
}
}
fd_set inset, outset, errset;
optimized_fd_set_t inset (nitems_);
optimized_fd_set_t outset (nitems_);
optimized_fd_set_t errset (nitems_);
#endif
bool first_pass = true;
@ -1041,18 +1068,23 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// Wait for events. Ignore interrupts if there's infinite timeout.
while (true) {
memcpy (&inset, &pollset_in, valid_pollset_bytes (pollset_in));
memcpy (&outset, &pollset_out, valid_pollset_bytes (pollset_out));
memcpy (&errset, &pollset_err, valid_pollset_bytes (pollset_err));
memcpy (inset.get (), pollset_in.get (),
valid_pollset_bytes (*pollset_in.get ()));
memcpy (outset.get (), pollset_out.get (),
valid_pollset_bytes (*pollset_out.get ()));
memcpy (errset.get (), pollset_err.get (),
valid_pollset_bytes (*pollset_err.get ()));
#if defined ZMQ_HAVE_WINDOWS
int rc = select (0, &inset, &outset, &errset, ptimeout);
int rc =
select (0, inset.get (), outset.get (), errset.get (), ptimeout);
if (unlikely (rc == SOCKET_ERROR)) {
errno = zmq::wsa_error_to_errno (WSAGetLastError ());
wsa_assert (errno == ENOTSOCK);
return -1;
}
#else
int rc = select (maxfd + 1, &inset, &outset, &errset, ptimeout);
int rc = select (maxfd + 1, inset.get (), outset.get (),
errset.get (), ptimeout);
if (unlikely (rc == -1)) {
errno_assert (errno == EINTR || errno == EBADF);
return -1;
@ -1084,11 +1116,11 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
// Else, the poll item is a raw file descriptor, simply convert
// the events to zmq_pollitem_t-style format.
else {
if (FD_ISSET (items_[i].fd, &inset))
if (FD_ISSET (items_[i].fd, inset.get ()))
items_[i].revents |= ZMQ_POLLIN;
if (FD_ISSET (items_[i].fd, &outset))
if (FD_ISSET (items_[i].fd, outset.get ()))
items_[i].revents |= ZMQ_POLLOUT;
if (FD_ISSET (items_[i].fd, &errset))
if (FD_ISSET (items_[i].fd, errset.get ()))
items_[i].revents |= ZMQ_POLLERR;
}