From 2b0a02d3df24b6f2705d85f7b8fe76acb9a62891 Mon Sep 17 00:00:00 2001 Message-Id: <2b0a02d3df24b6f2705d85f7b8fe76acb9a62891.1427300678.git.jen@redhat.com> In-Reply-To: References: From: Vlad Yasevich Date: Thu, 12 Mar 2015 19:13:11 -0500 Subject: [CHANGE 15/33] main-loop: switch to g_poll() on POSIX hosts To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Vlad Yasevich Message-id: <1426187601-21396-16-git-send-email-vyasevic@redhat.com> Patchwork-id: 64354 O-Subject: [RHEL6.7 qemu-kvm PATCH v2 15/25] main-loop: switch to g_poll() on POSIX hosts Bugzilla: 1005016 RH-Acked-by: Juan Quintela RH-Acked-by: Michael S. Tsirkin RH-Acked-by: Paolo Bonzini From: Stefan Hajnoczi 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 the temporary gpollfds_from_select() and gpollfds_to_select() functions and be left with native g_poll(2). On Windows things are a little crazy: convert from rfds/wfds/xfds to GPollFDs, back to rfds/wfds/xfds, call select(2), rfds/wfds/xfds back to GPollFDs, 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 GPollFDs -> select(2) -> GPollFDs sequence that allows Windows to use select(2) while the rest of QEMU only knows about GPollFD. Signed-off-by: Stefan Hajnoczi Reviewed-by: Laszlo Ersek Message-id: 1361356113-11049-3-git-send-email-stefanha@redhat.com Signed-off-by: Anthony Liguori (cherry picked from commit cbff4b342b000a7642125dbdabf61113e05eee44) Signed-off-by: Jeff E. Nelson Conflicts: main-loop.c main-loop.c doesn't exists in this version. Relevant code was added to vl.c. Win32 changes were dropped since we don't support it build and there is no way to test the change. A small change was picked from 15455536 to make the fdsets global. Signed-off-by: Vlad Yasevich --- vl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 70 insertions(+), 6 deletions(-) Signed-off-by: Jeff E. Nelson --- vl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 70 insertions(+), 6 deletions(-) diff --git a/vl.c b/vl.c index 24656c1..9020f0c 100644 --- a/vl.c +++ b/vl.c @@ -3555,9 +3555,12 @@ static int cpu_can_run(CPUState *env) return 1; } +static GArray *gpollfds; + #ifndef CONFIG_IOTHREAD static int qemu_init_main_loop(void) { + gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD)); return qemu_event_init(); } @@ -3656,6 +3659,7 @@ static int qemu_init_main_loop(void) if (ret) return ret; + gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD)); qemu_cond_init(&qemu_pause_cond); qemu_mutex_init(&qemu_fair_mutex); qemu_mutex_init(&qemu_global_mutex); @@ -3948,10 +3952,68 @@ void vm_stop(RunState reason) #endif +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 gpollfds. Will be removed a few commits later. */ +static void gpollfds_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) { + GPollFD pfd = { + .fd = fd, + .events = events, + }; + g_array_append_val(gpollfds, pfd); + } + } +} + +/* Store gpollfds revents into rfds/wfds/xfds. Will be removed a few commits + * later. + */ +static void gpollfds_to_select(int ret) +{ + int i; + + FD_ZERO(&rfds); + FD_ZERO(&wfds); + FD_ZERO(&xfds); + + if (ret <= 0) { + return; + } + + for (i = 0; i < gpollfds->len; i++) { + int fd = g_array_index(gpollfds, GPollFD, i).fd; + int revents = g_array_index(gpollfds, GPollFD, 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); + } + } +} + static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds, fd_set *xfds, int *cur_timeout) { @@ -4019,13 +4081,12 @@ static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds, void main_loop_wait(int timeout) { IOHandlerRecord *ioh; - fd_set rfds, wfds, xfds; - int ret, nfds; - struct timeval tv; + int ret; qemu_bh_update_timeout((uint32_t *)&timeout); /* poll any events */ + g_array_set_size(gpollfds, 0); /* reset for new iteration */ /* XXX: separate device handlers from system ones */ nfds = -1; FD_ZERO(&rfds); @@ -4055,12 +4116,15 @@ void main_loop_wait(int timeout) glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout); os_host_main_loop_wait(&timeout); - tv.tv_sec = timeout / 1000; - tv.tv_usec = (timeout % 1000) * 1000; + /* We'll eventually drop fd_set completely. But for now we still have + * *_fill() and *_poll() functions that use rfds/wfds/xfds. + */ + gpollfds_from_select(); qemu_mutex_unlock_iothread(); - ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv); + ret = g_poll((GPollFD *)gpollfds->data, gpollfds->len, timeout); qemu_mutex_lock_iothread(); + gpollfds_to_select(ret); if (ret > 0) { IOHandlerRecord *pioh; -- 2.1.0