Re: [PATCH 7/9] tools/virtio: use canonical ftrace path
flat view
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2023-01-30 19:27:46
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lkml, virtualization
On Mon, Jan 30, 2023 at 11:19:13AM -0700, Ross Zwisler wrote:
quoted hunk ↗ jump to hunk
The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing A few spots in tools/virtio still refer to this older debugfs path, so let's update them to avoid confusion. Signed-off-by: Ross Zwisler <redacted> --- tools/virtio/virtio-trace/README | 2 +- tools/virtio/virtio-trace/trace-agent.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)diff --git a/tools/virtio/virtio-trace/README b/tools/virtio/virtio-trace/README index b64845b823ab..cea29a2a4c0a 100644 --- a/tools/virtio/virtio-trace/README +++ b/tools/virtio/virtio-trace/README@@ -95,7 +95,7 @@ Run 1) Enable ftrace in the guest <Example> - # echo 1 > /sys/kernel/debug/tracing/events/sched/enable + # echo 1 > /sys/kernel/tracing/events/sched/enable 2) Run trace agent in the guest This agent must be operated as root.diff --git a/tools/virtio/virtio-trace/trace-agent.c b/tools/virtio/virtio-trace/trace-agent.c index cdfe77c2b4c8..805942d02e9f 100644 --- a/tools/virtio/virtio-trace/trace-agent.c +++ b/tools/virtio/virtio-trace/trace-agent.c@@ -19,7 +19,7 @@ #define PIPE_MIN_SIZE (PAGE_SIZE*PIPE_DEF_BUFS) #define PIPE_MAX_SIZE (1024*1024) #define READ_PATH_FMT \ - "/sys/kernel/debug/tracing/per_cpu/cpu%d/trace_pipe_raw" + "/sys/kernel/tracing/per_cpu/cpu%d/trace_pipe_raw"
Should we try both old and new path then?
#define WRITE_PATH_FMT "/dev/virtio-ports/trace-path-cpu%d" #define CTL_PATH "/dev/virtio-ports/agent-ctl-path" -- 2.39.1.456.gfc5497dd1b-goog