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[209.132.180.67]) by mx.google.com with ESMTP id n7si13809000pap.9.2015.09.06.00.16.32; Sun, 06 Sep 2015 00:16:33 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752792AbbIFHQa (ORCPT + 28 others); Sun, 6 Sep 2015 03:16:30 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:7444 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbbIFHPK (ORCPT ); Sun, 6 Sep 2015 03:15:10 -0400 Received: from 172.24.1.48 (EHLO SZXEML423-HUB.china.huawei.com) ([172.24.1.48]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CUK94034; Sun, 06 Sep 2015 15:14:10 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by SZXEML423-HUB.china.huawei.com (10.82.67.154) with Microsoft SMTP Server id 14.3.235.1; Sun, 6 Sep 2015 15:13:59 +0800 From: Wang Nan To: , , , CC: , , , , , , , , , , , Subject: [PATCH 06/27] perf bpf: Collect 'struct perf_probe_event' for bpf_program Date: Sun, 6 Sep 2015 07:13:22 +0000 Message-ID: <1441523623-152703-7-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> References: <1441523623-152703-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: wangnan0@huawei.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.44 as permitted sender) smtp.mailfrom=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , This patch utilizes bpf_program__set_private(), binding perf_probe_event with bpf program by private field. Saving those information so 'perf record' knows which kprobe point a program should be attached. Since data in 'struct perf_probe_event' is build by 2 stages, pev_ready is used to mark whether the information (especially tevs) in 'struct perf_probe_event' is valid or not. It is false at first, and set to true by sync_bpf_program_pev(), which copies all pointers in original pev into a program specific memory region. sync_bpf_program_pev() is called after apply_perf_probe_events() to make sure ready of data. Remove code which cleans 'struct perf_probe_event' after bpf__probe() because pointers in pevs are copied to program's private field, calling cleanup_perf_probe_events() becomes unsafe. Signed-off-by: Wang Nan Cc: Arnaldo Carvalho de Melo Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Daniel Borkmann Cc: David Ahern Cc: He Kuang Cc: Jiri Olsa Cc: Kaixu Xia Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/n/1436445342-1402-21-git-send-email-wangnan0@huawei.com [Splitted from a larger patch wangnan: Utilize new perf probe API {convert,apply,cleanup}_perf_probe_events() ] --- tools/perf/util/bpf-loader.c | 110 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 106 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 10505cb..ce95db8 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -30,9 +30,47 @@ DEFINE_PRINT_FN(debug, 1) static bool libbpf_initialized; +struct bpf_prog_priv { + /* + * If pev_ready is false, ppev pointes to a local memory which + * is only valid inside bpf__probe(). + * pev is valid only when pev_ready. + */ + bool pev_ready; + union { + struct perf_probe_event *ppev; + struct perf_probe_event pev; + }; +}; + +static void +bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, + void *_priv) +{ + struct bpf_prog_priv *priv = _priv; + + /* check if pev is initialized */ + if (priv && priv->pev_ready) { + int i; + + /* + * Similar code with cleanup_perf_probe_events, but without + * exit_symbol_maps(). + */ + for (i = 0; i < priv->pev.ntevs; i++) + clear_probe_trace_event(&priv->pev.tevs[i]); + zfree(&priv->pev.tevs); + priv->pev.ntevs = 0; + + clear_perf_probe_event(&priv->pev); + } + free(priv); +} + static int config_bpf_program(struct bpf_program *prog, struct perf_probe_event *pev) { + struct bpf_prog_priv *priv = NULL; const char *config_str; int err; @@ -74,14 +112,58 @@ config_bpf_program(struct bpf_program *prog, struct perf_probe_event *pev) pr_debug("bpf: config '%s' is ok\n", config_str); + priv = calloc(1, sizeof(*priv)); + if (!priv) { + pr_debug("bpf: failed to alloc memory\n"); + err = -ENOMEM; + goto errout; + } + + /* + * At this very early stage, tevs inside pev are not ready. + * It becomes usable after add_perf_probe_events() is called. + * set pev_ready to false so further access read priv->ppev + * only. + */ + priv->pev_ready = false; + priv->ppev = pev; + + err = bpf_program__set_private(prog, priv, + bpf_prog_priv__clear); + if (err) { + pr_debug("bpf: set program private failed\n"); + err = -ENOMEM; + goto errout; + } return 0; errout: if (pev) clear_perf_probe_event(pev); + if (priv) + free(priv); return err; } +static int +sync_bpf_program_pev(struct bpf_program *prog) +{ + int err; + struct bpf_prog_priv *priv; + struct perf_probe_event *ppev; + + err = bpf_program__get_private(prog, (void **)&priv); + if (err || !priv || priv->pev_ready) { + pr_debug("Internal error: sync_bpf_program_pev\n"); + return -EINVAL; + } + + ppev = priv->ppev; + memcpy(&priv->pev, ppev, sizeof(*ppev)); + priv->pev_ready = true; + return 0; +} + int bpf__prepare_load(const char *filename) { struct bpf_object *obj; @@ -186,15 +268,35 @@ int bpf__probe(void) } err = apply_perf_probe_events(pevs, nr_events); - if (err < 0) + if (err < 0) { pr_debug("bpf probe: failed to probe events\n"); - else + goto out_cleanup; + } else is_probed = true; -out_cleanup: - cleanup_perf_probe_events(pevs, nr_events); + + /* + * After add_perf_probe_events, 'struct perf_probe_event' is ready. + * Until now copying program's priv->pev field and freeing + * the big array allocated before become safe. + */ + bpf_object__for_each_safe(obj, tmp) { + bpf_object__for_each_program(prog, obj) { + err = sync_bpf_program_pev(prog); + if (err) + goto out; + } + } out: + /* + * Don't call cleanup_perf_probe_events() for entries of pevs: + * they are used by prog's private field. + */ free(pevs); return err < 0 ? err : 0; + +out_cleanup: + cleanup_perf_probe_events(pevs, nr_events); + goto out; } #define bpf__strerror_head(err, buf, size) \