在 2025/10/14 23:40, Steven Rostedt 写道:
On Tue, 14 Oct 2025 20:31:57 +0800 Shuai Xue <[email protected]> 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 <[email protected]> Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Shuai Xue <[email protected]> Reviewed-by: Lukas Wunner <[email protected]> Reviewed-by: Jonathan Cameron <[email protected]> --- drivers/pci/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 ++++ 5 files changed, 109 insertions(+), 6 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..58a4e4ea76b0 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -45,3 +45,6 @@ obj-y += controller/ obj-y += switch/subdir-ccflags-$(CONFIG_PCI_DEBUG) := -DDEBUG+ +CFLAGS_trace.o := -I$(src) +obj-$(CONFIG_TRACING) += trace.o diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index bcc938d4420f..7805f697a02c 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -19,6 +19,7 @@ #include <linux/types.h> #include <linux/pm_runtime.h> #include <linux/pci.h> +#include <trace/events/pci.h>#include "../pci.h"#include "pciehp.h" @@ -244,12 +245,20 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) case ON_STATE: ctrl->state = POWEROFF_STATE; mutex_unlock(&ctrl->state_lock); - if (events & PCI_EXP_SLTSTA_DLLSC) + if (events & PCI_EXP_SLTSTA_DLLSC) { ctrl_info(ctrl, "Slot(%s): Link Down\n", slot_name(ctrl)); - if (events & PCI_EXP_SLTSTA_PDC) + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_LINK_DOWN);I know this is v12 and I don't remember if I suggested this before and yougave me a reason already,
Aha, in our previous email discussions regarding the tracepoint implementation, you provided many constructive suggestions, so I added the Suggested-by tag. Perhaps I misunderstood the meaning of Suggested-by - I will drop it.
but why not simply pass in "ctrl" and have the TRACE_EVENT() denote the names?
Sure, I will send a version.
+ } + if (events & PCI_EXP_SLTSTA_PDC) { ctrl_info(ctrl, "Slot(%s): Card not present\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_NOT_PRESENT); + } pciehp_disable_slot(ctrl, SURPRISE_REMOVAL); break; default: @@ -269,6 +278,9 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) INDICATOR_NOOP); ctrl_info(ctrl, "Slot(%s): Card not present\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_NOT_PRESENT); } mutex_unlock(&ctrl->state_lock); return; @@ -281,12 +293,19 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) case OFF_STATE: ctrl->state = POWERON_STATE; mutex_unlock(&ctrl->state_lock); - if (present) + if (present) { ctrl_info(ctrl, "Slot(%s): Card present\n", slot_name(ctrl)); - if (link_active) - ctrl_info(ctrl, "Slot(%s): Link Up\n", - slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_CARD_PRESENT); + } + if (link_active) { + ctrl_info(ctrl, "Slot(%s): Link Up\n", slot_name(ctrl)); + trace_pci_hp_event(pci_name(ctrl->pcie->port), + slot_name(ctrl), + PCI_HOTPLUG_LINK_UP); + } ctrl->request_result = pciehp_enable_slot(ctrl); break; default: diff --git a/drivers/pci/trace.c b/drivers/pci/trace.c new file mode 100644 index 000000000000..cf11abca8602 --- /dev/null +++ b/drivers/pci/trace.c @@ -0,0 +1,11 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Tracepoints for PCI system + * + * Copyright (C) 2025 Alibaba Corporation + */ + +#include <linux/pci.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/pci.h> diff --git a/include/trace/events/pci.h b/include/trace/events/pci.h new file mode 100644 index 000000000000..208609492c06 --- /dev/null +++ b/include/trace/events/pci.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM pci + +#if !defined(_TRACE_HW_EVENT_PCI_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_HW_EVENT_PCI_H + +#include <linux/tracepoint.h> + +#define PCI_HOTPLUG_EVENT \ + EM(PCI_HOTPLUG_LINK_UP, "LINK_UP") \ + EM(PCI_HOTPLUG_LINK_DOWN, "LINK_DOWN") \ + EM(PCI_HOTPLUG_CARD_PRESENT, "CARD_PRESENT") \ + EMe(PCI_HOTPLUG_CARD_NOT_PRESENT, "CARD_NOT_PRESENT") + +/* Enums require being exported to userspace, for user tool parsing */ +#undef EM +#undef EMe +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define EMe(a, b) TRACE_DEFINE_ENUM(a); + +PCI_HOTPLUG_EVENT + +/* + * Now redefine the EM() and EMe() macros to map the enums to the strings + * that will be printed in the output. + */ +#undef EM +#undef EMe +#define EM(a, b) {a, b}, +#define EMe(a, b) {a, b} + +TRACE_EVENT(pci_hp_event, + + TP_PROTO(const char *port_name, + const char *slot, + const int event), + + TP_ARGS(port_name, slot, event), + + TP_STRUCT__entry( + __string( port_name, port_name ) + __string( slot, slot ) + __field( int, event ) + ),TP_PROTO(struct controller *ctrl, int event), TP_ARGS(ctrl, event), TP_STRUCT__entry( __string( port_name, pci_name(ctrl->pcie->port) ) __string( slot, slot_name(ctrl) ) __field( int, event ) ), It would move the work out of the calling path.
I see.
-- Steve
Thanks. Best Regards, Shuai
