This patch set is a different way to address the pressing need to access task_struct pointers in sched tracepoints from bpf programs. The first approach simply added these pointers to sched tracepoints: https://lkml.org/lkml/2017/12/14/753 which Peter nacked. Few options were discussed and eventually the discussion converged on doing bpf specific tracepoint_probe_register() probe functions. Details here: https://lkml.org/lkml/2017/12/20/929 Patch 1 is kernel wide cleanup of pass-struct-by-value into pass-struct-by-reference into tracepoints. Patch 2 minor prep work to expose number of arguments passed into tracepoints. Patch 3 introduces BPF_RAW_TRACEPOINT api. the auto-cleanup and multiple concurrent users are must have features of tracing api. For bpf raw tracepoints it looks like: // load bpf prog with BPF_PROG_TYPE_RAW_TRACEPOINT type prog_fd = bpf_prog_load(...); // receive anon_inode fd for given bpf_raw_tracepoint raw_tp_fd = bpf_raw_tracepoint_open("xdp_exception"); // attach bpf program to given tracepoint bpf_prog_attach(prog_fd, raw_tp_fd, BPF_RAW_TRACEPOINT); Ctrl-C of tracing daemon or cmdline tool will automatically detach bpf program, unload it and unregister tracepoint probe. More details in patch 3. Patch 4, 5 - user space lib and tests samples/bpf/test_overhead performance on 1 cpu: tracepoint base kprobe+bpf tracepoint+bpf raw_tracepoint+bpf task_rename 1.1M 769K 947K 1.0M urandom_read 789K 697K 750K 755K Alexei Starovoitov (5): treewide: remove struct-pass-by-value from tracepoints arguments tracepoint: compute num_args at build time bpf: introduce BPF_RAW_TRACEPOINT libbpf: add bpf_raw_tracepoint_open helper samples/bpf: raw tracepoint test arch/x86/xen/mmu_pv.c | 16 +-- drivers/gpu/drm/i915/i915_trace.h | 13 +- drivers/infiniband/hw/hfi1/file_ops.c | 2 +- drivers/infiniband/hw/hfi1/trace_ctxts.h | 12 +- drivers/s390/cio/ioasm.c | 18 +-- drivers/s390/cio/trace.h | 50 ++++---- fs/dax.c | 2 +- include/linux/bpf_types.h | 1 + include/linux/trace_events.h | 57 +++++++++ include/linux/tracepoint-defs.h | 1 + include/linux/tracepoint.h | 32 +++-- include/trace/bpf_probe.h | 87 +++++++++++++ include/trace/define_trace.h | 15 ++- include/trace/events/f2fs.h | 2 +- include/trace/events/fs_dax.h | 6 +- include/trace/events/rcu.h | 4 +- include/trace/events/xen.h | 32 ++--- include/uapi/linux/bpf.h | 11 ++ kernel/bpf/syscall.c | 108 ++++++++++++++++ kernel/rcu/tree.c | 10 +- kernel/trace/bpf_trace.c | 211 +++++++++++++++++++++++++++++++ kernel/tracepoint.c | 27 ++-- net/wireless/trace.h | 2 +- samples/bpf/Makefile | 1 + samples/bpf/bpf_load.c | 13 ++ samples/bpf/test_overhead_raw_tp_kern.c | 17 +++ samples/bpf/test_overhead_user.c | 12 ++ sound/firewire/amdtp-stream-trace.h | 2 +- tools/include/uapi/linux/bpf.h | 11 ++ tools/lib/bpf/bpf.c | 10 ++ tools/lib/bpf/bpf.h | 1 + 31 files changed, 677 insertions(+), 109 deletions(-) create mode 100644 include/trace/bpf_probe.h create mode 100644 samples/bpf/test_overhead_raw_tp_kern.c -- 2.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
