This patch allows creating only one BPF program for different 'probe_trace_event'(tev) generated by one 'perf_probe_event'(pev), if their prologues are identical.
This is done by comparing argument list of different tev, and maps type of prologue and tev using a mapping array. This patch utilizes qsort to sort tevs. After sorting, tevs with identical argument list will be grouped together. Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: Alexei Starovoitov <a...@plumgrid.com> Cc: Brendan Gregg <brendan.d.gr...@gmail.com> Cc: Daniel Borkmann <dan...@iogearbox.net> Cc: David Ahern <dsah...@gmail.com> Cc: He Kuang <heku...@huawei.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Kaixu Xia <xiaka...@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngk...@git.kernel.org --- tools/perf/util/bpf-loader.c | 133 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 126 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index c363907..af549ea 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -37,6 +37,8 @@ struct bpf_prog_priv { struct perf_probe_event pev; bool need_prologue; struct bpf_insn *insns_buf; + int nr_types; + int *type_mapping; }; struct bpf_object * @@ -104,6 +106,7 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, cleanup_perf_probe_events(&priv->pev, 1); zfree(&priv->insns_buf); + zfree(&priv->type_mapping); free(priv); } @@ -205,7 +208,7 @@ preproc_gen_prologue(struct bpf_program *prog, int n, struct bpf_prog_priv *priv; struct bpf_insn *buf; size_t prologue_cnt = 0; - int err; + int i, err; err = bpf_program__get_private(prog, (void **)&priv); if (err || !priv) @@ -213,10 +216,20 @@ preproc_gen_prologue(struct bpf_program *prog, int n, pev = &priv->pev; - if (n < 0 || n >= pev->ntevs) + if (n < 0 || n >= priv->nr_types) goto errout; - tev = &pev->tevs[n]; + /* Find a tev belongs to that type */ + for (i = 0; i < pev->ntevs; i++) + if (priv->type_mapping[i] == n) + break; + + if (i >= pev->ntevs) { + pr_debug("Internal error: prologue type %d not found\n", n); + return -ENOENT; + } + + tev = &pev->tevs[i]; buf = priv->insns_buf; err = bpf__gen_prologue(tev->args, tev->nargs, @@ -247,6 +260,98 @@ errout: return -EINVAL; } +/* + * compare_tev_args is reflexive, transitive and antisymmetric. + * I can show that but this margin is too narrow to contain. + */ +static int compare_tev_args(const void *ptev1, const void *ptev2) +{ + int i, ret; + const struct probe_trace_event *tev1 = + *(const struct probe_trace_event **)ptev1; + const struct probe_trace_event *tev2 = + *(const struct probe_trace_event **)ptev2; + + ret = tev2->nargs - tev1->nargs; + if (ret) + return ret; + + for (i = 0; i < tev1->nargs; i++) { + struct probe_trace_arg *arg1, *arg2; + struct probe_trace_arg_ref *ref1, *ref2; + + arg1 = &tev1->args[i]; + arg2 = &tev2->args[i]; + + ret = strcmp(arg1->value, arg2->value); + if (ret) + return ret; + + ref1 = arg1->ref; + ref2 = arg2->ref; + + while (ref1 && ref2) { + ret = ref2->offset - ref1->offset; + if (ret) + return ret; + + ref1 = ref1->next; + ref2 = ref2->next; + } + + if (ref1 || ref2) + return ref2 ? 1 : -1; + } + + return 0; +} + +static int map_prologue(struct perf_probe_event *pev, int *mapping, + int *nr_types) +{ + int i, type = 0; + struct { + struct probe_trace_event *tev; + int idx; + } *stevs; + size_t array_sz = sizeof(*stevs) * pev->ntevs; + + stevs = malloc(array_sz); + if (!stevs) { + pr_debug("No ehough memory: alloc stevs failed\n"); + return -ENOMEM; + } + + pr_debug("In map_prologue, ntevs=%d\n", pev->ntevs); + for (i = 0; i < pev->ntevs; i++) { + stevs[i].tev = &pev->tevs[i]; + stevs[i].idx = i; + } + qsort(stevs, pev->ntevs, sizeof(*stevs), + compare_tev_args); + + for (i = 0; i < pev->ntevs; i++) { + if (i == 0) { + mapping[stevs[i].idx] = type; + pr_debug("mapping[%d]=%d\n", stevs[i].idx, + type); + continue; + } + + if (compare_tev_args(stevs + i, stevs + i - 1) == 0) + mapping[stevs[i].idx] = type; + else + mapping[stevs[i].idx] = ++type; + + pr_debug("mapping[%d]=%d\n", stevs[i].idx, + mapping[stevs[i].idx]); + } + free(stevs); + *nr_types = type + 1; + + return 0; +} + static int hook_load_preprocessor(struct bpf_program *prog) { struct perf_probe_event *pev; @@ -286,7 +391,19 @@ static int hook_load_preprocessor(struct bpf_program *prog) return -ENOMEM; } - err = bpf_program__set_prep(prog, pev->ntevs, + priv->type_mapping = malloc(sizeof(int) * pev->ntevs); + if (!priv->type_mapping) { + pr_debug("No enough memory: alloc type_mapping failed\n"); + return -ENOMEM; + } + memset(priv->type_mapping, 0xff, + sizeof(int) * pev->ntevs); + + err = map_prologue(pev, priv->type_mapping, &priv->nr_types); + if (err) + return err; + + err = bpf_program__set_prep(prog, priv->nr_types, preproc_gen_prologue); return err; } @@ -420,9 +537,11 @@ int bpf__foreach_tev(struct bpf_object *obj, for (i = 0; i < pev->ntevs; i++) { tev = &pev->tevs[i]; - if (priv->need_prologue) - fd = bpf_program__nth_fd(prog, i); - else + if (priv->need_prologue) { + int type = priv->type_mapping[i]; + + fd = bpf_program__nth_fd(prog, type); + } else fd = bpf_program__fd(prog); if (fd < 0) { -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
