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由 Yonghong Song 提交于
This patch enables multiple bpf attachments for a kprobe/uprobe/tracepoint single trace event. Each trace_event keeps a list of attached perf events. When an event happens, all attached bpf programs will be executed based on the order of attachment. A global bpf_event_mutex lock is introduced to protect prog_array attaching and detaching. An alternative will be introduce a mutex lock in every trace_event_call structure, but it takes a lot of extra memory. So a global bpf_event_mutex lock is a good compromise. The bpf prog detachment involves allocation of memory. If the allocation fails, a dummy do-nothing program will replace to-be-detached program in-place. Signed-off-by: NYonghong Song <yhs@fb.com> Acked-by: NAlexei Starovoitov <ast@kernel.org> Acked-by: NMartin KaFai Lau <kafai@fb.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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