From: Masami Hiramatsu <mhiramat@redhat.com>
To: Ingo Molnar <mingo@elte.hu>, lkml<linux-kernel@vger.kernel.org>
Cc: Jason Baron <jbaron@redhat.com>,
Roland McGrath <roland@redhat.com>,
systemtap<systemtap@sources.redhat.com>,
DLE<dle-develop@lists.sourceforge.net>,
Masami Hiramatsu <mhiramat@redhat.com>,
Oleg Nesterov <oleg@redhat.com>,
Ingo Molnar <mingo@elte.hu>
Subject: [PATCH -tip v4 3/3] tracepoint: Add signal loss events
Date: Tue, 24 Nov 2009 21:54:00 -0000 [thread overview]
Message-ID: <20091124215658.30449.9934.stgit@dhcp-100-2-132.bos.redhat.com> (raw)
In-Reply-To: <20091124215638.30449.3838.stgit@dhcp-100-2-132.bos.redhat.com>
Add signal_overflow_fail and signal_lose_info tracepoints
for signal-lost events.
Changes in v3:
- Add docbook style comments
Changes in v2:
- Use siginfo string macro
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Suggested-by: Roland McGrath <roland@redhat.com>
Reviewed-by: Jason Baron <jbaron@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
---
include/trace/events/signal.h | 68 +++++++++++++++++++++++++++++++++++++++++
kernel/signal.c | 19 ++++++++---
2 files changed, 82 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index a6d71de..a510b75 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -99,6 +99,74 @@ TRACE_EVENT(signal_deliver,
__entry->sig, __entry->errno, __entry->code,
__entry->sa_handler, __entry->sa_flags)
);
+
+/**
+ * signal_overflow_fail - called when signal queue is overflow
+ * @sig: signal number
+ * @group: signal to process group or not (bool)
+ * @info: pointer to struct siginfo
+ *
+ * Kernel fails to generate 'sig' signal with 'info' siginfo, because
+ * siginfo queue is overflow, and the signal is dropped.
+ * 'group' is not 0 if the signal will be sent to a process group.
+ * 'sig' is always one of RT signals.
+ */
+TRACE_EVENT(signal_overflow_fail,
+
+ TP_PROTO(int sig, int group, struct siginfo *info),
+
+ TP_ARGS(sig, group, info),
+
+ TP_STRUCT__entry(
+ __field( int, sig )
+ __field( int, group )
+ __field( int, errno )
+ __field( int, code )
+ ),
+
+ TP_fast_assign(
+ __entry->sig = sig;
+ __entry->group = group;
+ TP_STORE_SIGINFO(__entry, info);
+ ),
+
+ TP_printk("sig=%d group=%d errno=%d code=%d",
+ __entry->sig, __entry->group, __entry->errno, __entry->code)
+);
+
+/**
+ * signal_lose_info - called when siginfo is lost
+ * @sig: signal number
+ * @group: signal to process group or not (bool)
+ * @info: pointer to struct siginfo
+ *
+ * Kernel generates 'sig' signal but loses 'info' siginfo, because siginfo
+ * queue is overflow.
+ * 'group' is not 0 if the signal will be sent to a process group.
+ * 'sig' is always one of non-RT signals.
+ */
+TRACE_EVENT(signal_lose_info,
+
+ TP_PROTO(int sig, int group, struct siginfo *info),
+
+ TP_ARGS(sig, group, info),
+
+ TP_STRUCT__entry(
+ __field( int, sig )
+ __field( int, group )
+ __field( int, errno )
+ __field( int, code )
+ ),
+
+ TP_fast_assign(
+ __entry->sig = sig;
+ __entry->group = group;
+ TP_STORE_SIGINFO(__entry, info);
+ ),
+
+ TP_printk("sig=%d group=%d errno=%d code=%d",
+ __entry->sig, __entry->group, __entry->errno, __entry->code)
+);
#endif /* _TRACE_SIGNAL_H */
/* This part must be outside protection */
diff --git a/kernel/signal.c b/kernel/signal.c
index d518984..6b982f2 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -919,12 +919,21 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
break;
}
} else if (!is_si_special(info)) {
- if (sig >= SIGRTMIN && info->si_code != SI_USER)
- /*
- * Queue overflow, abort. We may abort if the signal was rt
- * and sent by user using something other than kill().
- */
+ if (sig >= SIGRTMIN && info->si_code != SI_USER) {
+ /*
+ * Queue overflow, abort. We may abort if the
+ * signal was rt and sent by user using something
+ * other than kill().
+ */
+ trace_signal_overflow_fail(sig, group, info);
return -EAGAIN;
+ } else {
+ /*
+ * This is a silent loss of information. We still
+ * send the signal, but the *info bits are lost.
+ */
+ trace_signal_lose_info(sig, group, info);
+ }
}
out_set:
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-11-24 21:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-24 21:53 [PATCH -tip v4 0/3] tracepoint: Add signal events Masami Hiramatsu
2009-11-24 21:53 ` [PATCH -tip v4 1/3] tracepoint: Move signal sending tracepoint to events/signal.h Masami Hiramatsu
2009-11-26 10:27 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2009-11-24 21:54 ` Masami Hiramatsu [this message]
2009-11-26 10:27 ` [tip:perf/core] tracepoint: Add signal loss events tip-bot for Masami Hiramatsu
2009-11-24 21:54 ` [PATCH -tip v4 2/3] tracepoint: Add signal deliver event Masami Hiramatsu
2009-11-26 10:27 ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2009-11-24 22:12 ` [PATCH -tip v4 0/3] tracepoint: Add signal events Roland McGrath
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