Preliminary discussion: https://lkml.org/lkml/2020/5/13/1327 This patch avoids introducing arch-specific trace points by leveraging existing definition for ipi_raise.
Issues to address in potential future work: - make ipi reason available on generic smp code level (possible?) - addition of ipi_entry/ipi_exit tracepoints in generic smp code Signed-off-by: Wojciech Kudla <[email protected]> --- kernel/smp.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/smp.c b/kernel/smp.c index 7dbcb402c2fc..df6982a1d3f2 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -23,6 +23,11 @@ #include "smpboot.h" +#define CREATE_TRACE_POINTS +#include <trace/events/ipi.h> + +static const char *ipi_reason_missing __tracepoint_string = ""; + enum { CSD_FLAG_LOCK = 0x01, CSD_FLAG_SYNCHRONOUS = 0x02, @@ -34,6 +39,7 @@ struct call_function_data { cpumask_var_t cpumask_ipi; }; + static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data); static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue); @@ -176,8 +182,12 @@ static int generic_exec_single(int cpu, call_single_data_t *csd, * locking and barrier primitives. Generic code isn't really * equipped to do the right thing... */ - if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) + if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) { + if (trace_ipi_raise_enabled()) + trace_ipi_raise(cpumask_of(cpu), ipi_reason_missing); + arch_send_call_function_single_ipi(cpu); + } return 0; } @@ -474,6 +484,8 @@ void smp_call_function_many(const struct cpumask *mask, __cpumask_set_cpu(cpu, cfd->cpumask_ipi); } + trace_ipi_raise(cfd->cpumask_ipi, ipi_reason_missing); + /* Send a message to all CPUs in the map */ arch_send_call_function_ipi_mask(cfd->cpumask_ipi); -- 2.17.1
