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h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=J8SZk0InEttprJDG8mhzTigtAJH/J1bkTIxhCwzTmU0=; b=Dw+VcXvFWtGuNenkEtsfTh3g1xjYxDSW8O4jev99FvCELwD+/GBbx9VgCmf4WpHT+L+aWs PLOnwO3KPedWAcZXiO+BqCEjGQW8xPoxO/kWxbmihXP4JybM/TbvMxpNbXLLNRe2OxWEzw I6WXqNnJsv5XqqETMXRAFySvrysPDY+4foU6YCmHIjTXE+Ec6qZti3oR54F13rDSNrl5WK min9LNdMxJCLDS2V/xlfTfgZJKl7N50VvxF2G+0V9Jr/jwc4X04dNW2veFOginm7o9FjSL nTuYQDME14Z4Ihd1Csc4p/xEuInLCOPLJM/qDaDyyQsdcwARA78Un92YPtM+gw== From: Eugene Mavick Subject: [PATCH v3 0/5] tracing: add ref_trace_final_put tracing Date: Sat, 11 Jul 2026 12:40:18 +0800 Message-Id: <20260711-refcount-final-put-trace-v3-0-674c8f03d9f9@mavick.dev> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIADLJUWoC/53NPQ7CMAwF4KugzAQ5aZpQJu6BGNzYhQhoq7REI NS7E34GJpBYLD3L/t5NDBwDD2I1u4nIKQyha3Mo5jPh99juWAbKWWjQFqw2MnLju3M7yia0eJT 9eZRjRM/SVDU5X+RZosjvfb4Mlye92ea8D8PYxeuzKanH9oU6+IImJUHWZumMJVSNdusTpuAPC +L0KHkL5Q/BEwEoY7XF6j8BjaKiIeCl/VMA5KqwTLUr4VPYTtN0B/0hmgKHAQAA X-Change-ID: 20260624-refcount-final-put-trace-49bd7c39bd5a To: Will Deacon , Peter Zijlstra , Boqun Feng , Mark Rutland , Gary Guo , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, Eugene Mavick X-Developer-Signature: v=1; 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There is currently no universal way to trace this information. This patch series implements tracing of the final puts in the most widely used refcounting implementations, refcount_t(and thus kref which uses it), and percpu-ref. The tracepoint records three fields: - caller: function that called the refcounting function(refcount_sub_and_test, percpu_ref_put_many) - fn: refcounting function(eg refcount_sub_and_test) - obj: refcount object(struct percpu_ref, refcount_t) Signed-off-by: Eugene Mavick --- Changes in v2: -include/linux/ref_trace.h: change macro name, use direct tracepoint call in macro to avoid double check -add tracepoint to refcount_dec_if_one -kunit: make significant improvements to design, fix critical bug, add test case for refcount_dec_if_one() -Link to v1: https://lore.kernel.org/r/20260705-refcount-final-put-trace-v1-0-0ae936edb750@mavick.dev Changes in v3: include/trace/events/ref_trace.h kernel doc comments: -caller of refcount function -> return address of refcount function -ref_trace_final_put->do_ref_trace_final_put lib/ref_trace.c: add include trace/events/ref_trace.h kunit: -change Kconfig depends from FTRACE->TRACEPOINTS -EXPECT_FALSE->ASSERT_FALSE for calling percpu_ref_init -add tracepoint_synchronise_unregister to test_exit macro -added timeout to capture.count waiting -remove noinline and __always_inline from function attributes (added for testing, but accidentally submitted) -add period to the end of Kconfig help text v2 link: https://lore.kernel.org/all/20260710-refcount-final-put-trace-v2-0-557cfce860a2@mavick.dev/ --- Eugene Mavick (5): tracing: add ref_trace_final_put tracepoint refcount: add ref_trace_final_put tracepoint percpu-refcount: add ref_trace_final_put trace kunit: add test for ref_trace_final_put MAINTAINERS: add entries for ref_trace_final_put MAINTAINERS | 3 + include/linux/percpu-refcount.h | 5 +- include/linux/ref_trace.h | 26 ++++++++ include/linux/refcount.h | 2 + include/trace/events/ref_trace.h | 46 +++++++++++++ lib/Kconfig | 10 +++ lib/Makefile | 2 + lib/ref_trace.c | 13 ++++ lib/refcount.c | 8 ++- lib/tests/Makefile | 1 + lib/tests/ref_trace_kunit.c | 141 +++++++++++++++++++++++++++++++++++++++ 11 files changed, 255 insertions(+), 2 deletions(-) --- base-commit: df685633c3dbc67441cc86f1c3fee58de4652ba2 change-id: 20260624-refcount-final-put-trace-49bd7c39bd5a Best regards, -- Eugene Mavick