Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
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 v5 24/24] tracing/rseq: Add mm_vcpu_id field to rseq_update
Date:   Thu,  3 Nov 2022 16:03:59 -0400
Message-Id: <20221103200359.328736-25-mathieu.desnoyers@efficios.com>
In-Reply-To: <20221103200359.328736-1-mathieu.desnoyers@efficios.com>
References: <20221103200359.328736-1-mathieu.desnoyers@efficios.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Add the mm_vcpu_id field to the rseq_update event, allowing tracers to
follow which vcpu_id is observed by user-space, and whether negative
vcpu_id 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.
---
 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..9106148227c0 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_vcpu_id)
 	),
 
 	TP_fast_assign(
 		__entry->cpu_id = raw_smp_processor_id();
 		__entry->node_id = cpu_to_node(__entry->cpu_id);
+		__entry->mm_vcpu_id = task_mm_vcpu_id(t);
 	),
 
-	TP_printk("cpu_id=%d node_id=%d", __entry->cpu_id, __entry->node_id)
+	TP_printk("cpu_id=%d node_id=%d mm_vcpu_id=%d", __entry->cpu_id,
+		  __entry->node_id, __entry->mm_vcpu_id)
 );
 
 TRACE_EVENT(rseq_ip_fixup,
-- 
2.25.1