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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt17
-rw-r--r--arch/alpha/kernel/smp.c2
-rw-r--r--arch/arc/kernel/smp.c2
-rw-r--r--arch/arm/kernel/smp.c3
-rw-r--r--arch/arm/mach-actions/platsmp.c2
-rw-r--r--arch/arm64/kernel/smp.c3
-rw-r--r--arch/csky/kernel/smp.c2
-rw-r--r--arch/hexagon/kernel/smp.c2
-rw-r--r--arch/ia64/kernel/smp.c4
-rw-r--r--arch/loongarch/kernel/smp.c4
-rw-r--r--arch/mips/include/asm/smp.h2
-rw-r--r--arch/openrisc/kernel/smp.c2
-rw-r--r--arch/parisc/kernel/smp.c4
-rw-r--r--arch/powerpc/kernel/smp.c6
-rw-r--r--arch/powerpc/kvm/book3s_hv.c3
-rw-r--r--arch/powerpc/platforms/powernv/subcore.c2
-rw-r--r--arch/riscv/kernel/smp.c4
-rw-r--r--arch/s390/kernel/smp.c2
-rw-r--r--arch/sh/kernel/smp.c2
-rw-r--r--arch/sparc/kernel/smp_32.c2
-rw-r--r--arch/sparc/kernel/smp_64.c2
-rw-r--r--arch/x86/include/asm/smp.h2
-rw-r--r--arch/x86/kvm/svm/svm.c4
-rw-r--r--arch/x86/kvm/x86.c2
-rw-r--r--arch/xtensa/kernel/smp.c2
-rw-r--r--include/linux/smp.h11
-rw-r--r--include/trace/events/ipi.h44
-rw-r--r--kernel/irq_work.c12
-rw-r--r--kernel/sched/core.c22
-rw-r--r--kernel/sched/smp.h2
-rw-r--r--kernel/smp.c313
-rw-r--r--lib/Kconfig.debug9
-rw-r--r--virt/kvm/kvm_main.c3
33 files changed, 217 insertions, 281 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a38d55b6482c..b1453e0e3c95 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -912,15 +912,14 @@
cs89x0_media= [HW,NET]
Format: { rj45 | aui | bnc }
- csdlock_debug= [KNL] Enable debug add-ons of cross-CPU function call
- handling. When switched on, additional debug data is
- printed to the console in case a hanging CPU is
- detected, and that CPU is pinged again in order to try
- to resolve the hang situation.
- 0: disable csdlock debugging (default)
- 1: enable basic csdlock debugging (minor impact)
- ext: enable extended csdlock debugging (more impact,
- but more data)
+ csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
+ function call handling. When switched on,
+ additional debug data is printed to the console
+ in case a hanging CPU is detected, and that
+ CPU is pinged again in order to try to resolve
+ the hang situation. The default value of this
+ option depends on the CSD_LOCK_WAIT_DEBUG_DEFAULT
+ Kconfig option.
dasd= [HW,NET]
See header of drivers/s390/block/dasd_devmap.c.
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 0ede4b044e86..7439b2377df5 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -562,7 +562,7 @@ handle_ipi(struct pt_regs *regs)
}
void
-smp_send_reschedule(int cpu)
+arch_smp_send_reschedule(int cpu)
{
#ifdef DEBUG_IPI_MSG
if (cpu == hard_smp_processor_id())
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ad93fe6e4b77..409cfa4675b4 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -292,7 +292,7 @@ static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg)
ipi_send_msg_one(cpu, msg);
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
ipi_send_msg_one(cpu, IPI_RESCHEDULE);
}
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index f4a4ac028b6b..87f8d0e5e314 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -48,7 +48,6 @@
#include <asm/mach/arch.h>
#include <asm/mpu.h>
-#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>
/*
@@ -749,7 +748,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
ipi_setup(smp_processor_id());
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/arch/arm/mach-actions/platsmp.c b/arch/arm/mach-actions/platsmp.c
index f26618b43514..7b208e96fbb6 100644
--- a/arch/arm/mach-actions/platsmp.c
+++ b/arch/arm/mach-actions/platsmp.c
@@ -20,6 +20,8 @@
#include <asm/smp_plat.h>
#include <asm/smp_scu.h>
+#include <trace/events/ipi.h>
+
#define OWL_CPU1_ADDR 0x50
#define OWL_CPU1_FLAG 0x5c
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 05fe797e4203..d00d4cbb31b1 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -51,7 +51,6 @@
#include <asm/ptrace.h>
#include <asm/virt.h>
-#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>
DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
@@ -979,7 +978,7 @@ void __init set_smp_ipi_range(int ipi_base, int n)
ipi_setup(smp_processor_id());
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 9c7a20b73ac6..b12e2c3c387f 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -140,7 +140,7 @@ void smp_send_stop(void)
on_each_cpu(ipi_stop, NULL, 1);
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 4ba93e59370c..4e8bee25b8c6 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -217,7 +217,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
}
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
send_ipi(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index e2cc59db86bc..ea4f009a232b 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -220,11 +220,11 @@ kdump_smp_send_init(void)
* Called with preemption disabled.
*/
void
-smp_send_reschedule (int cpu)
+arch_smp_send_reschedule (int cpu)
{
ia64_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
}
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
/*
* Called with preemption disabled.
diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
index 51f328169a7b..ed167e244cda 100644
--- a/arch/loongarch/kernel/smp.c
+++ b/arch/loongarch/kernel/smp.c
@@ -155,11 +155,11 @@ void loongson_send_ipi_mask(const struct cpumask *mask, unsigned int action)
* it goes straight through and wastes no time serializing
* anything. Worst case is that we lose a reschedule ...
*/
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
loongson_send_ipi_single(cpu, SMP_RESCHEDULE);
}
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
{
diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h
index 4eee29b7845c..aab8981bc32c 100644
--- a/arch/mips/include/asm/smp.h
+++ b/arch/mips/include/asm/smp.h
@@ -66,7 +66,7 @@ extern void calculate_cpu_foreign_map(void);
* it goes straight through and wastes no time serializing
* anything. Worst case is that we lose a reschedule ...
*/
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
{
extern const struct plat_smp_ops *mp_ops; /* private */
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e1419095a6f0..0a7a059e2dff 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -173,7 +173,7 @@ void handle_IPI(unsigned int ipi_msg)
}
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 7dbd92cafae3..b7fc859fa87d 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -246,8 +246,8 @@ void kgdb_roundup_cpus(void)
inline void
smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
-void
-smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
+void
+arch_smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
void
smp_send_all_nop(void)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index bf9744034c3a..265801a3e94c 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -61,6 +61,8 @@
#include <asm/kup.h>
#include <asm/fadump.h>
+#include <trace/events/ipi.h>
+
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
@@ -364,12 +366,12 @@ static inline void do_message_pass(int cpu, int msg)
#endif
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
if (likely(smp_ops))
do_message_pass(cpu, PPC_MSG_RESCHEDULE);
}
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
void arch_send_call_function_single_ipi(int cpu)
{
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 6ba68dd6190b..3b70b5f80bd5 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -43,6 +43,7 @@
#include <linux/compiler.h>
#include <linux/of.h>
#include <linux/irqdomain.h>
+#include <linux/smp.h>
#include <asm/ftrace.h>
#include <asm/reg.h>
@@ -80,6 +81,8 @@
#include <asm/dtl.h>
#include <asm/plpar_wrappers.h>
+#include <trace/events/ipi.h>
+
#include "book3s.h"
#include "book3s_hv.h"
diff --git a/arch/powerpc/platforms/powernv/subcore.c b/arch/powerpc/platforms/powernv/subcore.c
index 428532a69762..191424468f10 100644
--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -20,6 +20,8 @@
#include <asm/opal.h>
#include <asm/smp.h>
+#include <trace/events/ipi.h>
+
#include "subcore.h"
#include "powernv.h"
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 5f985a197eff..23e533766a49 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -333,8 +333,8 @@ bool smp_crash_stop_failed(void)
}
#endif
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
send_ipi_single(cpu, IPI_RESCHEDULE);
}
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 4df797ab8ca2..70a84748f806 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -553,7 +553,7 @@ void arch_send_call_function_single_ipi(int cpu)
* it goes straight through and wastes no time serializing
* anything. Worst case is that we lose a reschedule ...
*/
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
}
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9ec245..5cf35a774dc7 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -256,7 +256,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
(bogosum / (5000/HZ)) % 100);
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
}
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index ad8094d955eb..87eaa7719fa2 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -120,7 +120,7 @@ void cpu_panic(void)
struct linux_prom_registers smp_penguin_ctable = { 0 };
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
/*
* CPU model dependent way of implementing IPI generation targeting
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index a55295d1b924..e5964d1d8b37 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1430,7 +1430,7 @@ static unsigned long send_cpu_poke(int cpu)
return hv_err;
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
if (cpu == smp_processor_id()) {
WARN_ON_ONCE(preemptible());
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 9fa795102b93..4e91054c84be 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -99,7 +99,7 @@ static inline void __noreturn play_dead(void)
BUG();
}
-static inline void smp_send_reschedule(int cpu)
+static inline void arch_smp_send_reschedule(int cpu)
{
smp_ops.smp_send_reschedule(cpu);
}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index f25bc3cbb250..a1b08359769b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -27,6 +27,7 @@
#include <linux/swap.h>
#include <linux/rwsem.h>
#include <linux/cc_platform.h>
+#include <linux/smp.h>
#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -41,6 +42,9 @@
#include <asm/fpu/api.h>
#include <asm/virtext.h>
+
+#include <trace/events/ipi.h>
+
#include "trace.h"
#include "svm.h"
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3d852ce84920..2b1d82647195 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -60,7 +60,9 @@
#include <linux/mem_encrypt.h>
#include <linux/entry-kvm.h>
#include <linux/suspend.h>
+#include <linux/smp.h>
+#include <trace/events/ipi.h>
#include <trace/events/kvm.h>
#include <asm/debugreg.h>
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 054bd64eab19..07dd6baf18cf 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -391,7 +391,7 @@ void arch_send_call_function_single_ipi(int cpu)
send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
}
-void smp_send_reschedule(int cpu)
+void arch_smp_send_reschedule(int cpu)
{
send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
}
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 7b93504eed26..91ea4a67f8ca 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -125,8 +125,15 @@ extern void smp_send_stop(void);
/*
* sends a 'reschedule' event to another CPU:
*/
-extern void smp_send_reschedule(int cpu);
-
+extern void arch_smp_send_reschedule(int cpu);
+/*
+ * scheduler_ipi() is inline so can't be passed as callback reason, but the
+ * callsite IP should be sufficient for root-causing IPIs sent from here.
+ */
+#define smp_send_reschedule(cpu) ({ \
+ trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \
+ arch_smp_send_reschedule(cpu); \
+})
/*
* Prepare machine for booting other CPUs.
diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
index 0be71dad6ec0..3de9bfc982ce 100644
--- a/include/trace/events/ipi.h
+++ b/include/trace/events/ipi.h
@@ -35,6 +35,50 @@ TRACE_EVENT(ipi_raise,
TP_printk("target_mask=%s (%s)", __get_bitmask(target_cpus), __entry->reason)
);
+TRACE_EVENT(ipi_send_cpu,
+
+ TP_PROTO(const unsigned int cpu, unsigned long callsite, void *callback),
+
+ TP_ARGS(cpu, callsite, callback),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, cpu)
+ __field(void *, callsite)
+ __field(void *, callback)
+ ),
+
+ TP_fast_assign(
+ __entry->cpu = cpu;
+ __entry->callsite = (void *)callsite;
+ __entry->callback = callback;
+ ),
+
+ TP_printk("cpu=%u callsite=%pS callback=%pS",
+ __entry->cpu, __entry->callsite, __entry->callback)
+);
+
+TRACE_EVENT(ipi_send_cpumask,
+
+ TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+ TP_ARGS(cpumask, callsite, callback),
+
+ TP_STRUCT__entry(
+ __cpumask(cpumask)
+ __field(void *, callsite)
+ __field(void *, callback)
+ ),
+
+ TP_fast_assign(
+ __assign_cpumask(cpumask, cpumask_bits(cpumask));
+ __entry->callsite = (void *)callsite;
+ __entry->callback = callback;
+ ),
+
+ TP_printk("cpumask=%s callsite=%pS callback=%pS",
+ __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
DECLARE_EVENT_CLASS(ipi_handler,
TP_PROTO(const char *reason),
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 7afa40fe5cc4..2f4fb336dda1 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -22,6 +22,8 @@
#include <asm/processor.h>
#include <linux/kasan.h>
+#include <trace/events/ipi.h>
+
static DEFINE_PER_CPU(struct llist_head, raised_list);
static DEFINE_PER_CPU(struct llist_head, lazy_list);
static DEFINE_PER_CPU(struct task_struct *, irq_workd);
@@ -74,6 +76,14 @@ void __weak arch_irq_work_raise(void)
*/
}
+static __always_inline void irq_work_raise(struct irq_work *work)
+{
+ if (trace_ipi_send_cpu_enabled() && arch_irq_work_has_interrupt())
+ trace_ipi_send_cpu(smp_processor_id(), _RET_IP_, work->func);
+
+ arch_irq_work_raise();
+}
+
/* Enqueue on current CPU, work must already be claimed and preempt disabled */
static void __irq_work_queue_local(struct irq_work *work)
{
@@ -99,7 +109,7 @@ static void __irq_work_queue_local(struct irq_work *work)
/* If the work is "lazy", handle it from next tick if any */
if (!lazy_work || tick_nohz_tick_stopped())
- arch_irq_work_raise();
+ irq_work_raise(work);
}
/* Enqueue the irq work @work on the current CPU */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 54c75af24899..944c3ae39861 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -80,6 +80,7 @@
#define CREATE_TRACE_POINTS
#include <linux/sched/rseq_api.h>
#include <trace/events/sched.h>
+#include <trace/events/ipi.h>
#undef CREATE_TRACE_POINTS
#include "sched.h"
@@ -95,6 +96,9 @@
#include "../../io_uring/io-wq.h"
#include "../smpboot.h"
+EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpu);
+EXPORT_TRACEPOINT_SYMBOL_GPL(ipi_send_cpumask);
+
/*
* Export tracepoints that act as a bare tracehook (ie: have no trace event
* associated with them) to allow external modules to probe them.
@@ -3848,14 +3852,20 @@ void sched_ttwu_pending(void *arg)
rq_unlock_irqrestore(rq, &rf);
}
-void send_call_function_single_ipi(int cpu)
+/*
+ * Prepare the scene for sending an IPI for a remote smp_call
+ *
+ * Returns true if the caller can proceed with sending the IPI.
+ * Returns false otherwise.
+ */
+bool call_function_single_prep_ipi(int cpu)
{
- struct rq *rq = cpu_rq(cpu);
-
- if (!set_nr_if_polling(rq->idle))
- arch_send_call_function_single_ipi(cpu);
- else
+ if (set_nr_if_polling(cpu_rq(cpu)->idle)) {
trace_sched_wake_idle_without_ipi(cpu);
+ return false;
+ }
+
+ return true;
}
/*
diff --git a/kernel/sched/smp.h b/kernel/sched/smp.h
index 2eb23dd0f285..21ac44428bb0 100644
--- a/kernel/sched/smp.h
+++ b/kernel/sched/smp.h
@@ -6,7 +6,7 @@
extern void sched_ttwu_pending(void *arg);
-extern void send_call_function_single_ipi(int cpu);
+extern bool call_function_single_prep_ipi(int cpu);
#ifdef CONFIG_SMP
extern void flush_smp_call_function_queue(void);
diff --git a/kernel/smp.c b/kernel/smp.c
index 06a413987a14..ab3e5dad6cfe 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -26,68 +26,15 @@
#include <linux/sched/debug.h>
#include <linux/jump_label.h>
+#include <trace/events/ipi.h>
+
#include "smpboot.h"
#include "sched/smp.h"
#define CSD_TYPE(_csd) ((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK)
-#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
-union cfd_seq_cnt {
- u64 val;
- struct {
- u64 src:16;
- u64 dst:16;
-#define CFD_SEQ_NOCPU 0xffff
- u64 type:4;
-#define CFD_SEQ_QUEUE 0
-#define CFD_SEQ_IPI 1
-#define CFD_SEQ_NOIPI 2
-#define CFD_SEQ_PING 3
-#define CFD_SEQ_PINGED 4
-#define CFD_SEQ_HANDLE 5
-#define CFD_SEQ_DEQUEUE 6
-#define CFD_SEQ_IDLE 7
-#define CFD_SEQ_GOTIPI 8
-#define CFD_SEQ_HDLEND 9
- u64 cnt:28;
- } u;
-};
-
-static char *seq_type[] = {
- [CFD_SEQ_QUEUE] = "queue",
- [CFD_SEQ_IPI] = "ipi",
- [CFD_SEQ_NOIPI] = "noipi",
- [CFD_SEQ_PING] = "ping",
- [CFD_SEQ_PINGED] = "pinged",
- [CFD_SEQ_HANDLE] = "handle",
- [CFD_SEQ_DEQUEUE] = "dequeue (src CPU 0 == empty)",
- [CFD_SEQ_IDLE] = "idle",
- [CFD_SEQ_GOTIPI] = "gotipi",
- [CFD_SEQ_HDLEND] = "hdlend (src CPU 0 == early)",
-};
-
-struct cfd_seq_local {
- u64 ping;
- u64 pinged;
- u64 handle;
- u64 dequeue;
- u64 idle;
- u64 gotipi;
- u64 hdlend;
-};
-#endif
-
-struct cfd_percpu {
- call_single_data_t csd;
-#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
- u64 seq_queue;
- u64 seq_ipi;
- u64 seq_noipi;
-#endif
-};
-
struct call_function_data {
- struct cfd_percpu __percpu *pcpu;
+ call_single_data_t __percpu *csd;
cpumask_var_t cpumask;
cpumask_var_t cpumask_ipi;
};
@@ -110,8 +57,8 @@ int smpcfd_prepare_cpu(unsigned int cpu)
free_cpumask_var(cfd->cpumask);
return -ENOMEM;
}
- cfd->pcpu = alloc_percpu(struct cfd_percpu);
- if (!cfd->pcpu) {
+ cfd->csd = alloc_percpu(call_single_data_t);
+ if (!cfd->csd) {
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
return -ENOMEM;
@@ -126,7 +73,7 @@ int smpcfd_dead_cpu(unsigned int cpu)
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
- free_percpu(cfd->pcpu);
+ free_percpu(cfd->csd);
return 0;
}
@@ -156,23 +103,49 @@ void __init call_function_init(void)
smpcfd_prepare_cpu(smp_processor_id());
}
+static __always_inline void
+send_call_function_single_ipi(int cpu)
+{
+ if (call_function_single_prep_ipi(cpu)) {
+ trace_ipi_send_cpu(cpu, _RET_IP_,
+ generic_smp_call_function_single_interrupt);
+ arch_send_call_function_single_ipi(cpu);
+ }
+}
+
+static __always_inline void
+send_call_function_ipi_mask(struct cpumask *mask)
+{
+ trace_ipi_send_cpumask(mask, _RET_IP_,
+ generic_smp_call_function_single_interrupt);
+ arch_send_call_function_ipi_mask(mask);
+}
+
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
-static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
-static DEFINE_STATIC_KEY_FALSE(csdlock_debug_extended);
+static DEFINE_STATIC_KEY_MAYBE(CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT, csdlock_debug_enabled);
+/*
+ * Parse the csdlock_debug= kernel boot parameter.
+ *
+ * If you need to restore the old "ext" value that once provided
+ * additional debugging information, reapply the following commits:
+ *
+ * de7b09ef658d ("locking/csd_lock: Prepare more CSD lock debugging")
+ * a5aabace5fb8 ("locking/csd_lock: Add more data to CSD lock debugging")
+ */
static int __init csdlock_debug(char *str)
{
+ int ret;
unsigned int val = 0;
- if (str && !strcmp(str, "ext")) {
- val = 1;
- static_branch_enable(&csdlock_debug_extended);
- } else
- get_option(&str, &val);
-
- if (val)
- static_branch_enable(&csdlock_debug_enabled);
+ ret = get_option(&str, &val);
+ if (ret) {
+ if (val)
+ static_branch_enable(&csdlock_debug_enabled);
+ else
+ static_branch_disable(&csdlock_debug_enabled);
+ }
return 1;
}
@@ -181,36 +154,11 @@ __setup("csdlock_debug=", csdlock_debug);
static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);
static DEFINE_PER_CPU(void *, cur_csd_info);
-static DEFINE_PER_CPU(struct cfd_seq_local, cfd_seq_local);
static ulong csd_lock_timeout = 5000; /* CSD lock timeout in milliseconds. */
module_param(csd_lock_timeout, ulong, 0444);
static atomic_t csd_bug_count = ATOMIC_INIT(0);
-static u64 cfd_seq;
-
-#define CFD_SEQ(s, d, t, c) \
- (union cfd_seq_cnt){ .u.src = s, .u.dst = d, .u.type = t, .u.cnt = c }
-
-static u64 cfd_seq_inc(unsigned int src, unsigned int dst, unsigned int type)
-{
- union cfd_seq_cnt new, old;
-
- new = CFD_SEQ(src, dst, type, 0);
-
- do {
- old.val = READ_ONCE(cfd_seq);
- new.u.cnt = old.u.cnt + 1;
- } while (cmpxchg(&cfd_seq, old.val, new.val) != old.val);
-
- return old.val;
-}
-
-#define cfd_seq_store(var, src, dst, type) \
- do { \
- if (static_branch_unlikely(&csdlock_debug_extended)) \
- var = cfd_seq_inc(src, dst, type); \
- } while (0)
/* Record current CSD work for current CPU, NULL to erase. */
static void __csd_lock_record(struct __call_single_data *csd)
@@ -244,80 +192,6 @@ static int csd_lock_wait_getcpu(struct __call_single_data *csd)
return -1;
}
-static void cfd_seq_data_add(u64 val, unsigned int src, unsigned int dst,
- unsigned int type, union cfd_seq_cnt *data,
- unsigned int *n_data, unsigned int now)
-{
- union cfd_seq_cnt new[2];
- unsigned int i, j, k;
-
- new[0].val = val;
- new[1] = CFD_SEQ(src, dst, type, new[0].u.cnt + 1);
-
- for (i = 0; i < 2; i++) {
- if (new[i].u.cnt <= now)
- new[i].u.cnt |= 0x80000000U;
- for (j = 0; j < *n_data; j++) {
- if (new[i].u.cnt == data[j].u.cnt) {
- /* Direct read value trumps generated one. */
- if (i == 0)
- data[j].val = new[i].val;
- break;
- }
- if (new[i].u.cnt < data[j].u.cnt) {
- for (k = *n_data; k > j; k--)
- data[k].val = data[k - 1].val;
- data[j].val = new[i].val;
- (*n_data)++;
- break;
- }
- }
- if (j == *n_data) {
- data[j].val = new[i].val;
- (*n_data)++;
- }
- }
-}
-
-static const char *csd_lock_get_type(unsigned int type)
-{
- return (type >= ARRAY_SIZE(seq_type)) ? "?" : seq_type[type];
-}
-
-static void csd_lock_print_extended(struct __call_single_data *csd, int cpu)
-{
- struct cfd_seq_local *seq = &per_cpu(cfd_seq_local, cpu);
- unsigned int srccpu = csd->node.src;
- struct call_function_data *cfd = per_cpu_ptr(&cfd_data, srccpu);
- struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
- unsigned int now;
- union cfd_seq_cnt data[2 * ARRAY_SIZE(seq_type)];
- unsigned int n_data = 0, i;
-
- data[0].val = READ_ONCE(cfd_seq);
- now = data[0].u.cnt;
-
- cfd_seq_data_add(pcpu->seq_queue, srccpu, cpu, CFD_SEQ_QUEUE, data, &n_data, now);
- cfd_seq_data_add(pcpu->seq_ipi, srccpu, cpu, CFD_SEQ_IPI, data, &n_data, now);
- cfd_seq_data_add(pcpu->seq_noipi, srccpu, cpu, CFD_SEQ_NOIPI, data, &n_data, now);
-
- cfd_seq_data_add(per_cpu(cfd_seq_local.ping, srccpu), srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PING, data, &n_data, now);
- cfd_seq_data_add(per_cpu(cfd_seq_local.pinged, srccpu), srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED, data, &n_data, now);
-
- cfd_seq_data_add(seq->idle, CFD_SEQ_NOCPU, cpu, CFD_SEQ_IDLE, data, &n_data, now);
- cfd_seq_data_add(seq->gotipi, CFD_SEQ_NOCPU, cpu, CFD_SEQ_GOTIPI, data, &n_data, now);
- cfd_seq_data_add(seq->handle, CFD_SEQ_NOCPU, cpu, CFD_SEQ_HANDLE, data, &n_data, now);
- cfd_seq_data_add(seq->dequeue, CFD_SEQ_NOCPU, cpu, CFD_SEQ_DEQUEUE, data, &n_data, now);
- cfd_seq_data_add(seq->hdlend, CFD_SEQ_NOCPU, cpu, CFD_SEQ_HDLEND, data, &n_data, now);
-
- for (i = 0; i < n_data; i++) {
- pr_alert("\tcsd: cnt(%07x): %04x->%04x %s\n",
- data[i].u.cnt & ~0x80000000U, data[i].u.src,
- data[i].u.dst, csd_lock_get_type(data[i].u.type));
- }
- pr_alert("\tcsd: cnt now: %07x\n", now);
-}
-
/*
* Complain if too much time spent waiting. Note that only
* the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
@@ -368,8 +242,6 @@ static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *
*bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
}
if (cpu >= 0) {
- if (static_branch_unlikely(&csdlock_debug_extended))
- csd_lock_print_extended(csd, cpu);
dump_cpu_task(cpu);
if (!cpu_cur_csd) {
pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
@@ -412,27 +284,7 @@ static __always_inline void csd_lock_wait(struct __call_single_data *csd)
smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
}
-
-static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
-{
- unsigned int this_cpu = smp_processor_id();
- struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
- struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
- struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
-
- cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
- if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
- cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
- cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
- send_call_function_single_ipi(cpu);
- cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
- } else {
- cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
- }
-}
#else
-#define cfd_seq_store(var, src, dst, type)
-
static void csd_lock_record(struct __call_single_data *csd)
{
}
@@ -470,23 +322,29 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
void __smp_call_single_queue(int cpu, struct llist_node *node)
{
-#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
- if (static_branch_unlikely(&csdlock_debug_extended)) {
- unsigned int type;
-
- type = CSD_TYPE(container_of(node, call_single_data_t,
- node.llist));
- if (type == CSD_TYPE_SYNC || type == CSD_TYPE_ASYNC) {
- __smp_call_single_queue_debug(cpu, node);
- return;
- }
+ /*
+ * We have to check the type of the CSD before queueing it, because
+ * once queued it can have its flags cleared by
+ * flush_smp_call_function_queue()
+ * even if we haven't sent the smp_call IPI yet (e.g. the stopper
+ * executes migration_cpu_stop() on the remote CPU).
+ */
+ if (trace_ipi_send_cpu_enabled()) {
+ call_single_data_t *csd;
+ smp_call_func_t func;
+
+ csd = container_of(node, call_single_data_t, node.llist);
+ func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
+ sched_ttwu_pending : csd->func;
+
+ trace_ipi_send_cpu(cpu, _RET_IP_, func);
}
-#endif
/*
- * The list addition should be visible before sending the IPI
- * handler locks the list to pull the entry off it because of
- * normal cache coherency rules implied by spinlocks.
+ * The list addition should be visible to the target CPU when it pops
+ * the head of the list to pull the entry off it in the IPI handler
+ * because of normal cache coherency rules implied by the underlying
+ * llist ops.
*
* If IPIs can go out of order to the cache coherency protocol
* in an architecture, sufficient synchronisation should be added
@@ -541,8 +399,6 @@ static int generic_exec_single(int cpu, struct __call_single_data *csd)
*/
void generic_smp_call_function_single_interrupt(void)
{
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU,
- smp_processor_id(), CFD_SEQ_GOTIPI);
__flush_smp_call_function_queue(true);
}
@@ -570,13 +426,7 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline)
lockdep_assert_irqs_disabled();
head = this_cpu_ptr(&call_single_queue);
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->handle, CFD_SEQ_NOCPU,
- smp_processor_id(), CFD_SEQ_HANDLE);
entry = llist_del_all(head);
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->dequeue,
- /* Special meaning of source cpu: 0 == queue empty */
- entry ? CFD_SEQ_NOCPU : 0,
- smp_processor_id(), CFD_SEQ_DEQUEUE);
entry = llist_reverse_order(entry);
/* There shouldn't be any pending callbacks on an offline CPU. */
@@ -635,12 +485,8 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline)
}
}
- if (!entry) {
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend,
- 0, smp_processor_id(),
- CFD_SEQ_HDLEND);
+ if (!entry)
return;
- }
/*
* Second; run all !SYNC callbacks.
@@ -678,9 +524,6 @@ static void __flush_smp_call_function_queue(bool warn_cpu_offline)
*/
if (entry)
sched_ttwu_pending(entry);
-
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend, CFD_SEQ_NOCPU,
- smp_processor_id(), CFD_SEQ_HDLEND);
}
@@ -704,8 +547,6 @@ void flush_smp_call_function_queue(void)
if (llist_empty(this_cpu_ptr(&call_single_queue)))
return;
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU,
- smp_processor_id(), CFD_SEQ_IDLE);
local_irq_save(flags);
/* Get the already pending soft interrupts for RT enabled kernels */
was_pending = local_softirq_pending();
@@ -887,9 +728,9 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
int cpu, last_cpu, this_cpu = smp_processor_id();
struct call_function_data *cfd;
bool wait = scf_flags & SCF_WAIT;
+ int nr_cpus = 0, nr_queued = 0;
bool run_remote = false;
bool run_local = false;
- int nr_cpus = 0;
lockdep_assert_preemption_disabled();
@@ -929,11 +770,12 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
- struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
- call_single_data_t *csd = &pcpu->csd;
+ call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
- if (cond_func && !cond_func(cpu, info))
+ if (cond_func && !cond_func(cpu, info)) {
+ __cpumask_clear_cpu(cpu, cfd->cpumask);
continue;
+ }
csd_lock(csd);
if (wait)
@@ -944,19 +786,20 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
#endif
- cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
nr_cpus++;
last_cpu = cpu;
-
- cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
- } else {
- cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
}
+ nr_queued++;
}
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PING);
+ /*
+ * Trace each smp_function_call_*() as an IPI, actual IPIs
+ * will be traced with func==generic_smp_call_function_single_ipi().
+ */
+ if (nr_queued)
+ trace_ipi_send_cpumask(cfd->cpumask, _RET_IP_, func);
/*
* Choose the most efficient way to send an IPI. Note that the
@@ -966,9 +809,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
if (nr_cpus == 1)
send_call_function_single_ipi(last_cpu);
else if (likely(nr_cpus > 1))
- arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
-
- cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
+ send_call_function_ipi_mask(cfd->cpumask_ipi);
}
if (run_local && (!cond_func || cond_func(this_cpu, info))) {
@@ -983,7 +824,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd;
- csd = &per_cpu_ptr(cfd->pcpu, cpu)->csd;
+ csd = per_cpu_ptr(cfd->csd, cpu);
csd_lock_wait(csd);
}
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index be272aa2fc0a..d49d7c5e12ec 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1490,6 +1490,15 @@ config CSD_LOCK_WAIT_DEBUG
include the IPI handler function currently executing (if any)
and relevant stack traces.
+config CSD_LOCK_WAIT_DEBUG_DEFAULT
+ bool "Default csd_lock_wait() debugging on at boot time"
+ depends on CSD_LOCK_WAIT_DEBUG
+ depends on 64BIT
+ default n
+ help
+ This option causes the csdlock_debug= kernel boot parameter to
+ default to 1 (basic debugging) instead of 0 (no debugging).
+
endmenu # lock debugging
config TRACE_IRQFLAGS
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b1679d08a216..537f33ac49de 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -62,11 +62,14 @@
#include "kvm_mm.h"
#include "vfio.h"
+#include <trace/events/ipi.h>
+
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
#include <linux/kvm_dirty_ring.h>
+
/* Worst case buffer size needed for holding an integer. */
#define ITOA_MAX_LEN 12