From patchwork Wed Feb 10 23:23:46 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 78600 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o1ANRdYL007653 for ; Wed, 10 Feb 2010 23:27:40 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756627Ab0BJX1i (ORCPT ); Wed, 10 Feb 2010 18:27:38 -0500 Received: from mail-fx0-f220.google.com ([209.85.220.220]:59829 "EHLO mail-fx0-f220.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756099Ab0BJX1h (ORCPT ); Wed, 10 Feb 2010 18:27:37 -0500 Received: by fxm20 with SMTP id 20so616151fxm.21 for ; Wed, 10 Feb 2010 15:27:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:from:to:cc:subject :date:message-id:x-mailer; bh=hiBM9vUueIu8WHLc8MJrM7NsoreXhnXncPjghnZC6Zc=; b=O4d0ZjgooT9iKEl6TvjL7cHM21zQQ/A6muHKD4MQS7vsKdbo9adKC1SmKF3Co5bTok alccB7f/RnVXIz4jDsbGGUGg/e8GbOGwNkJCmF5uyF/nnpZIyNVCYJJT4Z7bMlCyIRdu XiIxoTJHFJDnO8D4sD15vMQhjupTAQxCw+uk0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:from:to:cc:subject:date:message-id:x-mailer; b=wDkDRhgH1YP4MOi7vv1LiHBbF3zdv4yNv2QLmVAa5CioSRT82gDdsIbDYwDH+74lF4 +oS1MK6lPYgVjQBqKmMl4MgMJbERnMCdnrI7eNKr+I/Jtqh1nITCGNTRXXGAErT5soy3 fuHavF2nLVZaZxDtAoOE1/x/XHfzySSzm78Zc= Received: by 10.223.2.194 with SMTP id 2mr1022883fak.30.1265844232779; Wed, 10 Feb 2010 15:23:52 -0800 (PST) Received: from localhost.localdomain ([85.93.118.17]) by mx.google.com with ESMTPS id p17sm551885fka.35.2010.02.10.15.23.49 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 10 Feb 2010 15:23:52 -0800 (PST) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org Subject: [PATCH] [uq/master] use eventfd for iothread Date: Thu, 11 Feb 2010 00:23:46 +0100 Message-Id: <1265844226-29613-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.6.6 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Wed, 10 Feb 2010 23:27:43 +0000 (UTC) diff --git a/osdep.c b/osdep.c index 9059f01..9e4b17b 100644 --- a/osdep.c +++ b/osdep.c @@ -37,6 +37,10 @@ #include #endif +#ifdef CONFIG_EVENTFD +#include +#endif + #ifdef _WIN32 #include #elif defined(CONFIG_BSD) @@ -281,6 +285,34 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count) #ifndef _WIN32 /* + * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set. + */ +int qemu_eventfd(int fds[2]) +{ + int ret; + +#ifdef CONFIG_EVENTFD + ret = eventfd(0, 0); + if (ret >= 0) { + fds[0] = ret; + qemu_set_cloexec(ret); + if ((fds[1] = dup(ret)) == -1) { + close(ret); + return -1; + } + qemu_set_cloexec(fds[1]); + return 0; + } + + if (errno != ENOSYS) { + return -1; + } +#endif + + return qemu_pipe(fds); +} + +/* * Creates a pipe with FD_CLOEXEC set on both file descriptors */ int qemu_pipe(int pipefd[2]) diff --git a/qemu-common.h b/qemu-common.h index b09f717..c941006 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -170,6 +170,7 @@ ssize_t qemu_write_full(int fd, const void *buf, size_t count) void qemu_set_cloexec(int fd); #ifndef _WIN32 +int qemu_eventfd(int pipefd[2]); int qemu_pipe(int pipefd[2]); #endif diff --git a/vl.c b/vl.c index 98918ac..1957018 100644 --- a/vl.c +++ b/vl.c @@ -3211,14 +3211,15 @@ static int io_thread_fd = -1; static void qemu_event_increment(void) { - static const char byte = 0; + /* Write 8 bytes to be compatible with eventfd. */ + static uint64_t val = 1; ssize_t ret; if (io_thread_fd == -1) return; do { - ret = write(io_thread_fd, &byte, sizeof(byte)); + ret = write(io_thread_fd, &val, sizeof(val)); } while (ret < 0 && errno == EINTR); /* EAGAIN is fine, a read must be pending. */ @@ -3235,7 +3236,7 @@ static void qemu_event_read(void *opaque) ssize_t len; char buffer[512]; - /* Drain the notify pipe */ + /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */ do { len = read(fd, buffer, sizeof(buffer)); } while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); @@ -3246,7 +3247,7 @@ static int qemu_event_init(void) int err; int fds[2]; - err = qemu_pipe(fds); + err = qemu_eventfd(fds); if (err == -1) return -errno;