在 2025/6/2 14:30, Ilpo Järvinen 写道:

On Mon, 12 May 2025, Shuai Xue wrote:

quoted

Hotplug events are critical indicators for analyzing hardware health,
particularly in AI supercomputers where surprise link downs can
significantly impact system performance and reliability.

To this end, define a new TRACING_SYSTEM named pci, add a generic RAS
tracepoint for hotplug event to help healthy check, and generate
tracepoints for pcie hotplug event. Add enum pci_hotplug_event in
include/uapi/linux/pci.h so applications like rasdaemon can register
tracepoint event handlers for it.

The output like below:

$ echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable
$ cat /sys/kernel/debug/tracing/trace_pipe
     <...>-206     [001] .....    40.373870: pci_hp_event: 0000:00:02.0 slot:10, event:Link Down

     <...>-206     [001] .....    40.374871: pci_hp_event: 0000:00:02.0 slot:10, event:Card not present

Suggested-by: Lukas Wunner <lukas@wunner.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
changes since v7:
- replace the TRACE_INCLUDE_PATH to avoid macro conflict per Steven
- pick up Reviewed-by from Lukas Wunner
---
  drivers/pci/hotplug/Makefile      |  3 ++
  drivers/pci/hotplug/pciehp_ctrl.c | 33 ++++++++++++---
  drivers/pci/hotplug/trace.h       | 68 +++++++++++++++++++++++++++++++
  include/uapi/linux/pci.h          |  7 ++++
  4 files changed, 105 insertions(+), 6 deletions(-)
  create mode 100644 drivers/pci/hotplug/trace.h

diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
index 40aaf31fe338..a1a9d1e98962 100644
--- a/drivers/pci/hotplug/Makefile
+++ b/drivers/pci/hotplug/Makefile

@@ -3,6 +3,9 @@
  # Makefile for the Linux kernel pci hotplug controller drivers.
  #
  
+# define_trace.h needs to know how to find our header
+CFLAGS_pciehp_ctrl.o				:= -I$(src)
+
  obj-$(CONFIG_HOTPLUG_PCI)		+= pci_hotplug.o
  obj-$(CONFIG_HOTPLUG_PCI_COMPAQ)	+= cpqphp.o
  obj-$(CONFIG_HOTPLUG_PCI_IBM)		+= ibmphp.o

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index d603a7aa7483..f9beb4d3a9b8 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c

@@ -23,6 +23,9 @@
  #include "../pci.h"
  #include "pciehp.h"
  
+#define CREATE_TRACE_POINTS
+#include "trace.h"

Hi,

Instead of spreading tracepoint creating into subdriver code like this,
should we place it into one place, e.g., drivers/pci/pci-trace.c (which is
what I seem to have used in my yet to be submitted patch that adds
tracepoints into bwctrl link speed events)?

quoted

diff --git a/drivers/pci/hotplug/trace.h b/drivers/pci/hotplug/trace.h
new file mode 100644
index 000000000000..21329c198019
--- /dev/null
+++ b/drivers/pci/hotplug/trace.h

Perhaps in include/trace/events/pci.h (or
include/trace/events/pci-hotplug.h)?

I don't know what is the general rule having them inside drivers/ vs
include/trace/events, Documentation/trace/tracepoints.rst only mentions
the latter, but there seems to be plenty under drivers/ too.

Hi, Ilpo,

I don't know either.

I think it is tracepoint stuff and it is up to @Steve.
@Steve, which way do you prefer?

Thanks for help.

Best Regards,
Shuai