This patchset adds tracepoints around mmap_lock acquisition. This is useful so we can measure the latency of lock acquisition, in order to detect contention. This version is based upon linux-next (since it depends on some recently-merged patches [1] [2]), and incorporates feedback from the review of the previous version: - Functions renamed to reserve the "trace_" prefix for actual tracepoints. - We no longer measure the duration directly. Instead, users are expected to construct a synthetic event which computes the interval between "start locking" and "acquire returned". - The new helper for checking if tracepoints are enabled in a header is used to avoid un-inlining any of the lock wrappers. This yields ~zero overhead if the tracepoints aren't enabled, and therefore obviates the need for a Kconfig for this change. [1] https://lore.kernel.org/patchwork/patch/1316922/ [2] https://lore.kernel.org/patchwork/patch/1311996/ Axel Rasmussen (2): tracing: support "bool" type in synthetic trace events mmap_lock: add tracepoints around lock acquisition include/linux/mmap_lock.h | 112 +++++++++++++++++++++++++++--- include/trace/events/mmap_lock.h | 70 +++++++++++++++++++ kernel/trace/trace_events_synth.c | 4 ++ mm/Makefile | 2 +- mm/mmap_lock.c | 87 +++++++++++++++++++++++ 5 files changed, 265 insertions(+), 10 deletions(-) create mode 100644 include/trace/events/mmap_lock.h create mode 100644 mm/mmap_lock.c -- 2.28.0.806.g8561365e88-goog
