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From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        "H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
        linux-api@vger.kernel.org, Christian Brauner <brauner@kernel.org>,
        Florian Weimer <fw@deneb.enyo.de>, David.Laight@ACULAB.COM,
        carlos@redhat.com, Peter Oskolkov <posk@posk.io>,
        Alexander Mikhalitsyn <alexander@mihalicyn.com>,
        Chris Kennelly <ckennelly@google.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [PATCH 21/30] tracing/rseq: Add mm_cid field to rseq_update
Date:   Tue, 22 Nov 2022 15:39:23 -0500
Message-Id: <20221122203932.231377-22-mathieu.desnoyers@efficios.com>
In-Reply-To: <20221122203932.231377-1-mathieu.desnoyers@efficios.com>
References: <20221122203932.231377-1-mathieu.desnoyers@efficios.com>
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Add the mm_cid field to the rseq_update event, allowing tracers to
follow which mm_cid is observed by user-space, and whether negative
mm_cid values are visible in case of internal scheduler implementation
issues.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
Changes since v4:
- use task_mm_vcpu_id() to get the mm_vcpu_id from the task struct.

Changes since v5:
- rename vcpu_id to mm_cid.
---
 include/trace/events/rseq.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/rseq.h b/include/trace/events/rseq.h
index dde7a359b4ef..823b47d1ba1e 100644
--- a/include/trace/events/rseq.h
+++ b/include/trace/events/rseq.h
@@ -17,14 +17,17 @@ TRACE_EVENT(rseq_update,
 	TP_STRUCT__entry(
 		__field(s32, cpu_id)
 		__field(s32, node_id)
+		__field(s32, mm_cid)
 	),
 
 	TP_fast_assign(
 		__entry->cpu_id = raw_smp_processor_id();
 		__entry->node_id = cpu_to_node(__entry->cpu_id);
+		__entry->mm_cid = task_mm_cid(t);
 	),
 
-	TP_printk("cpu_id=%d node_id=%d", __entry->cpu_id, __entry->node_id)
+	TP_printk("cpu_id=%d node_id=%d mm_cid=%d", __entry->cpu_id,
+		  __entry->node_id, __entry->mm_cid)
 );
 
 TRACE_EVENT(rseq_ip_fixup,
-- 
2.25.1