On Thu, Mar 17, 2016 at 8:23 PM, Stefan Hajnoczi <stefa...@gmail.com> wrote:
> On Tue, Mar 15, 2016 at 11:55:13PM +0530, Pooja Dhannawat wrote: > > nc_sendv_compat has a huge stack usage of 69680 bytes approx. > > Moving large arrays to heap to reduce stack usage. > > > > Signed-off-by: Pooja Dhannawat <dhannawatpoo...@gmail.com> > > --- > > net/net.c | 14 ++++++++++---- > > 1 file changed, 10 insertions(+), 4 deletions(-) > > > > diff --git a/net/net.c b/net/net.c > > index b0c832e..f03c571 100644 > > --- a/net/net.c > > +++ b/net/net.c > > @@ -709,23 +709,29 @@ ssize_t qemu_send_packet_raw(NetClientState *nc, > const uint8_t *buf, int size) > > static ssize_t nc_sendv_compat(NetClientState *nc, const struct iovec > *iov, > > int iovcnt, unsigned flags) > > { > > - uint8_t buf[NET_BUFSIZE]; > > + uint8_t *buf; > > uint8_t *buffer; > > size_t offset; > > + ssize_t ret; > > + > > + buf = g_new(uint8_t, NET_BUFSIZE); > > The linear buffer is only needed when iovcnt > 1. I suggest the > following instead: > > uint8_t *buf = NULL; > > if (iovcnt == 1) { > buffer = iov[0].iov_base; > offset = iov[0].iov_len; > } else { > buf = g_new(uint8_t, NET_BUFSIZE); > buffer = buf; > offset = iov_to_buf(iov, iovcnt, 0, buf, NET_BUFSIZE); > } > > This way the allocation is only made when we actually need to linearize > the buffer. > Thanks Stefan for pointing out this one :) I will make desired changes and push patch.