From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60241) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1afRte-0001XM-TF for qemu-devel@nongnu.org; Mon, 14 Mar 2016 08:46:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1afRtb-0007Q1-Nx for qemu-devel@nongnu.org; Mon, 14 Mar 2016 08:46:54 -0400 Received: from mail-wm0-x243.google.com ([2a00:1450:400c:c09::243]:34799) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1afRtb-0007PK-Gw for qemu-devel@nongnu.org; Mon, 14 Mar 2016 08:46:51 -0400 Received: by mail-wm0-x243.google.com with SMTP id p65so14907039wmp.1 for ; Mon, 14 Mar 2016 05:46:51 -0700 (PDT) From: Nikos Filippakis Date: Mon, 14 Mar 2016 14:46:42 +0200 Message-Id: <1457959602-6472-1-git-send-email-aesmade@gmail.com> Subject: [Qemu-devel] [PATCH v3] net.c: Moved large array in nc_sendv_compat from the stack to the heap List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Nikos Filippakis , jasowang@redhat.com Allocate array in nc_sendv_compat on the heap if it is large to reduce stack frame size, as stated in the BiteSizedTasks wiki page. Signed-off-by: Nikos Filippakis --- net/net.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) diff --git a/net/net.c b/net/net.c index b0c832e..a9be287 100644 --- a/net/net.c +++ b/net/net.c @@ -709,23 +709,41 @@ 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 *buffer; - size_t offset; + const size_t STACKBUF_SIZE = 2048; + + uint8_t *buffer, *dynbuf = NULL; + uint8_t stackbuf[STACKBUF_SIZE]; + size_t offset, iov_len; + ssize_t ret; if (iovcnt == 1) { buffer = iov[0].iov_base; offset = iov[0].iov_len; } else { - buffer = buf; - offset = iov_to_buf(iov, iovcnt, 0, buf, sizeof(buf)); + iov_len = iov_size(iov, iovcnt); + + if (iov_len <= STACKBUF_SIZE) { + buffer = stackbuf; + } else if (iov_len <= NET_BUFSIZE) { + buffer = dynbuf = g_new(uint8_t, iov_len); + } else { + errno = EINVAL; + return 0; + } + + offset = iov_to_buf(iov, iovcnt, 0, buffer, + NET_BUFSIZE * sizeof(uint8_t)); } if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) { - return nc->info->receive_raw(nc, buffer, offset); + ret = nc->info->receive_raw(nc, buffer, offset); } else { - return nc->info->receive(nc, buffer, offset); + ret = nc->info->receive(nc, buffer, offset); } + + g_free(dynbuf); + + return ret; } ssize_t qemu_deliver_packet_iov(NetClientState *sender, -- 1.9.1