Re: [PATCH v10 1/3] PCI: trace: Add a generic RAS tracepoint for hotplug event

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Tue, 23 Sep 2025, Ilpo Järvinen wrote:

> On Tue, 23 Sep 2025, Shuai Xue wrote:
> 
> > 
> > 
> > 在 2025/9/23 14:46, Ilpo Järvinen 写道:
> > > On Tue, 23 Sep 2025, Shuai Xue wrote:
> > > 
> > > > 
> > > > 
> > > > 在 2025/9/22 21:10, Ilpo Järvinen 写道:
> > > > > On Sat, 20 Sep 2025, Shuai Xue wrote:
> > > > > 
> > > > > > Hotplug events are critical indicators for analyzing hardware health,
> > > > > > and surprise link downs can significantly impact system performance
> > > > > > and
> > > > > > reliability.
> > > > > > 
> > > > > > Define a new TRACING_SYSTEM named "pci", add a generic RAS tracepoint
> > > > > > for hotplug event to help health checks. Add enum pci_hotplug_event in
> > > > > > include/uapi/linux/pci.h so applications like rasdaemon can register
> > > > > > tracepoint event handlers for it.
> > > > > > 
> > > > > > The following output is generated when a device is hotplugged:
> > > > > > 
> > > > > > $ echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable
> > > > > > $ cat /sys/kernel/debug/tracing/trace_pipe
> > > > > >      irq/51-pciehp-88      [001] .....  1311.177459: pci_hp_event:
> > > > > > 0000:00:02.0 slot:10, event:CARD_PRESENT
> > > > > > 
> > > > > >      irq/51-pciehp-88      [001] .....  1311.177566: pci_hp_event:
> > > > > > 0000:00:02.0 slot:10, event:LINK_UP
> > > > > > 
> > > > > > 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>
> > > > > > ---
> > > > > >    drivers/pci/Makefile              |  2 +
> > > > > >    drivers/pci/hotplug/Makefile      |  3 +-
> > > > > >    drivers/pci/hotplug/pciehp_ctrl.c | 31 ++++++++++++---
> > > > > >    drivers/pci/trace.c               | 11 ++++++
> > > > > >    include/trace/events/pci.h        | 63
> > > > > > +++++++++++++++++++++++++++++++
> > > > > >    include/uapi/linux/pci.h          |  7 ++++
> > > > > >    6 files changed, 110 insertions(+), 7 deletions(-)
> > > > > >    create mode 100644 drivers/pci/trace.c
> > > > > >    create mode 100644 include/trace/events/pci.h
> > > > > > 
> > > > > > diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> > > > > > index 67647f1880fb..bf389bc4dd3c 100644
> > > > > > --- a/drivers/pci/Makefile
> > > > > > +++ b/drivers/pci/Makefile
> > > > > > @@ -45,3 +45,5 @@ obj-y				+= controller/
> > > > > >    obj-y				+= switch/
> > > > > >      subdir-ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG
> > > > > > +
> > > > > > +CFLAGS_trace.o := -I$(src)
> > > > > > diff --git a/drivers/pci/hotplug/Makefile
> > > > > > b/drivers/pci/hotplug/Makefile
> > > > > > index 40aaf31fe338..d41f7050b072 100644
> > > > > > --- a/drivers/pci/hotplug/Makefile
> > > > > > +++ b/drivers/pci/hotplug/Makefile
> > > > > > @@ -65,7 +65,8 @@ rpadlpar_io-objs	:=	rpadlpar_core.o \
> > > > > >    pciehp-objs		:=	pciehp_core.o	\
> > > > > >    				pciehp_ctrl.o	\
> > > > > >    				pciehp_pci.o	\
> > > > > > -				pciehp_hpc.o
> > > > > > +				pciehp_hpc.o	\
> > > > > > +				../trace.o
> > > > > 
> > > > > To make it useful for any PCI tracing, not juse hotplug, this object
> > > > > file
> > > > > should be added in drivers/pci/Makefile, not here.
> > > > 
> > > > Make sence. How about adding to the main CONFIG_PCI object:
> > > > 
> > > > diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
> > > > index bf389bc4dd3c..d7f83d06351d 100644
> > > > --- a/drivers/pci/Makefile
> > > > +++ b/drivers/pci/Makefile
> > > > @@ -5,7 +5,7 @@
> > > >   obj-$(CONFIG_PCI)              += access.o bus.o probe.o host-bridge.o \
> > > >                                     remove.o pci.o pci-driver.o search.o \
> > > >                                     rom.o setup-res.o irq.o vpd.o \
> > > > -                                  setup-bus.o vc.o mmap.o devres.o
> > > > +                                  setup-bus.o vc.o mmap.o devres.o
> > > > trace.o
> > > > 
> > > >   obj-$(CONFIG_PCI)              += msi/
> > > >   obj-$(CONFIG_PCI)              += pcie/
> > > 
> > > Yes, that's the right place to add it.
> > > 
> > 
> > Thanks for confirm.
> > Will send a new version to fix it.
> 
> I actually now started to wonder if it should be made depend on some 
> tracing related config (sending this out quickly if you were just 
> waiting for my confirmation to send quickly... I'm still investigating
> what other subsystems do).

Probably this is what we actually want:

obj-$(CONFIG_TRACING)			+= trace.o

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 i.