From patchwork Thu Jan 31 10:53:57 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 217163 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id D79AC2C0040 for ; Thu, 31 Jan 2013 22:34:14 +1100 (EST) Received: from localhost ([::1]:52847 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0rnF-0001Uh-Ub for incoming@patchwork.ozlabs.org; Thu, 31 Jan 2013 05:54:57 -0500 Received: from eggs.gnu.org ([208.118.235.92]:38074) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0rmj-000061-3E for qemu-devel@nongnu.org; Thu, 31 Jan 2013 05:54:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U0rme-00043s-2x for qemu-devel@nongnu.org; Thu, 31 Jan 2013 05:54:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44869) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U0rmd-00043Z-RS for qemu-devel@nongnu.org; Thu, 31 Jan 2013 05:54:20 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0VAsI3j029310 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 31 Jan 2013 05:54:18 -0500 Received: from localhost (ovpn-112-28.ams2.redhat.com [10.36.112.28]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r0VAsHJa012116; Thu, 31 Jan 2013 05:54:17 -0500 From: Stefan Hajnoczi To: Date: Thu, 31 Jan 2013 11:53:57 +0100 Message-Id: <1359629644-21920-5-git-send-email-stefanha@redhat.com> In-Reply-To: <1359629644-21920-1-git-send-email-stefanha@redhat.com> References: <1359629644-21920-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Anthony Liguori , Jan Kiszka , Fabien Chouteau , Stefan Hajnoczi , Paolo Bonzini , Amos Kong Subject: [Qemu-devel] [PATCH 04/11] main-loop: switch to g_poll() on POSIX hosts X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Use g_poll(3) instead of select(2). Well, this is kind of a cheat. It's true that we're now using g_poll(3) on POSIX hosts but the *_fill() and *_poll() functions are still using rfds/wfds/xfds. We've set the scene to start converting *_fill() and *_poll() functions step-by-step until no more rfds/wfds/xfds users remain. Then we'll drop poller_from_select() and poller_to_select() completely and be left with native g_poll(2). On Windows things are a little crazy: convert from rfds/wfds/xfds to Poller, back to rfds/wfds/xfds, call select(2), rfds/wfds/xfds back to Poller, and finally back to rfds/wfds/xfds again. This is only temporary and keeps the Windows build working through the following patches. We'll drop this excessive conversion later and be left with a single Poller -> select(2) -> Poller sequence that allows Windows to use select(2) while the rest of QEMU only knows about Poller. Signed-off-by: Stefan Hajnoczi --- main-loop.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 73 insertions(+), 8 deletions(-) diff --git a/main-loop.c b/main-loop.c index d0d8fe4..8d552d4 100644 --- a/main-loop.c +++ b/main-loop.c @@ -26,6 +26,7 @@ #include "qemu/timer.h" #include "slirp/slirp.h" #include "qemu/main-loop.h" +#include "qemu/poller.h" #include "block/aio.h" #ifndef _WIN32 @@ -140,12 +141,65 @@ int qemu_init_main_loop(void) return 0; } +static Poller poller; static fd_set rfds, wfds, xfds; static int nfds; static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */ static int n_poll_fds; static int max_priority; +/* Load rfds/wfds/xfds into Poller. Will be removed a few commits later. */ +static void poller_from_select(void) +{ + int fd; + for (fd = 0; fd <= nfds; fd++) { + int events = 0; + if (FD_ISSET(fd, &rfds)) { + events |= G_IO_IN | G_IO_HUP | G_IO_ERR; + } + if (FD_ISSET(fd, &wfds)) { + events |= G_IO_OUT | G_IO_ERR; + } + if (FD_ISSET(fd, &xfds)) { + events |= G_IO_PRI; + } + if (events) { + poller_add_fd(&poller, fd, events); + } + } +} + +/* Store Poller revents into rfds/wfds/xfds. Will be removed a few commits + * later. + */ +static void poller_to_select(int ret) +{ + int i; + + FD_ZERO(&rfds); + FD_ZERO(&wfds); + FD_ZERO(&xfds); + + if (ret <= 0) { + return; + } + + for (i = 0; i < poller.nfds; i++) { + int fd = poller.poll_fds[i].fd; + int revents = poller.poll_fds[i].revents; + + if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) { + FD_SET(fd, &rfds); + } + if (revents & (G_IO_OUT | G_IO_ERR)) { + FD_SET(fd, &wfds); + } + if (revents & G_IO_PRI) { + FD_SET(fd, &xfds); + } + } +} + #ifndef _WIN32 static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds, fd_set *xfds, uint32_t *cur_timeout) @@ -212,22 +266,22 @@ static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds, static int os_host_main_loop_wait(uint32_t timeout) { - struct timeval tv, *tvarg = NULL; int ret; glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout); - if (timeout < UINT32_MAX) { - tvarg = &tv; - tv.tv_sec = timeout / 1000; - tv.tv_usec = (timeout % 1000) * 1000; - } - if (timeout > 0) { qemu_mutex_unlock_iothread(); } - ret = select(nfds + 1, &rfds, &wfds, &xfds, tvarg); + /* We'll eventually drop fd_set completely. But for now we still have + * *_fill() and *_poll() functions that use rfds/wfds/xfds. + */ + poller_from_select(); + + ret = g_poll(poller.poll_fds, poller.nfds, timeout); + + poller_to_select(ret); if (timeout > 0) { qemu_mutex_lock_iothread(); @@ -382,12 +436,22 @@ static int os_host_main_loop_wait(uint32_t timeout) * improve socket latency. */ + /* This back-and-forth between Poller and select(2) is temporary. We'll + * drop it in a couple of patches, I promise :). + */ + poller_from_select(); + FD_ZERO(&rfds); + FD_ZERO(&wfds); + FD_ZERO(&xfds); + nfds = poller_fill(&poller, &rfds, &wfds, &xfds); if (nfds >= 0) { select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0); if (select_ret != 0) { timeout = 0; + poller_poll(&poller, nfds, &rfds, &wfds, &xfds); } } + poller_to_select(select_ret || g_poll_ret); return select_ret || g_poll_ret; } @@ -403,6 +467,7 @@ int main_loop_wait(int nonblocking) } /* poll any events */ + poller_reset(&poller); /* XXX: separate device handlers from system ones */ nfds = -1; FD_ZERO(&rfds);