From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Amit Shah <amit.shah@redhat.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@amd64.org>,
"Franch Ch. Eigler" <fche@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Herbert Xu <herbert@gondor.hengli.com.au>,
Ingo Molnar <mingo@redhat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org,
yrl.pp-manager.tt@hitachi.com,
Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Subject: [PATCH 4/5] trace-cmd: Add non-blocking option for open() and splice_read()
Date: Wed, 22 Aug 2012 17:43:32 +0900 [thread overview]
Message-ID: <20120822084332.17293.84508.stgit@ltc189.sdl.hitachi.co.jp> (raw)
In-Reply-To: <20120822084251.17293.69086.stgit@ltc189.sdl.hitachi.co.jp>
Add non-blocking option for open() and splice_read() for avoiding block to read
trace data of a guest from FIFO.
If SIGINT comes to read/write processes from the parent process in the case
where FIFO as a read I/F is assigned, then reading is normally blocked for
splice_read(). So, we added nonblock option to open() and splice_read().
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
---
trace-recorder.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/trace-recorder.c b/trace-recorder.c
index 3b750e9..6577fe8 100644
--- a/trace-recorder.c
+++ b/trace-recorder.c
@@ -124,7 +124,7 @@ struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu)
goto out_free;
sprintf(path, "%s/per_cpu/cpu%d/trace_pipe_raw", tracing, cpu);
- recorder->trace_fd = open(path, O_RDONLY);
+ recorder->trace_fd = open(path, O_RDONLY | O_NONBLOCK);
if (recorder->trace_fd < 0)
goto out_free;
@@ -172,14 +172,17 @@ static long splice_data(struct tracecmd_recorder *recorder)
long ret;
ret = splice(recorder->trace_fd, NULL, recorder->brass[1], NULL,
- recorder->page_size, 1 /* SPLICE_F_MOVE */);
+ recorder->page_size, SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
if (ret < 0) {
- warning("recorder error in splice input");
- return -1;
+ if (errno != EAGAIN) {
+ warning("recorder error in splice input");
+ return -1;
+ }
+ return 0; /* Buffer is empty */
}
ret = splice(recorder->brass[0], NULL, recorder->fd, NULL,
- recorder->page_size, 3 /* and NON_BLOCK */);
+ recorder->page_size, SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
if (ret < 0) {
if (errno != EAGAIN) {
warning("recorder error in splice output");
next prev parent reply other threads:[~2012-08-22 8:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 8:42 [PATCH 0/5] trace-cmd: Add a recorder readable feature for virtio-trace Yoshihiro YUNOMAE
2012-08-22 8:43 ` [PATCH 1/5] trace-cmd: Use TRACE_DIR envrionment variable if defined Yoshihiro YUNOMAE
2012-08-22 13:37 ` Steven Rostedt
2012-08-22 8:43 ` [PATCH 2/5] trace-cmd: Use tracing directory to count CPUs Yoshihiro YUNOMAE
2012-08-22 13:41 ` Steven Rostedt
2012-08-23 2:01 ` Masami Hiramatsu
2012-08-23 3:00 ` Masami Hiramatsu
2012-08-23 9:08 ` Steven Rostedt
2012-08-23 12:30 ` Masami Hiramatsu
2012-08-22 8:43 ` [PATCH 3/5] trace-cmd: Support trace-agent of virtio-trace Yoshihiro YUNOMAE
2012-08-22 13:51 ` Steven Rostedt
2012-08-23 3:13 ` Yoshihiro YUNOMAE
2012-08-22 8:43 ` Yoshihiro YUNOMAE [this message]
2012-08-22 8:43 ` [PATCH 5/5] trace-cmd: Use polling function Yoshihiro YUNOMAE
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