From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D8C1C83F33 for ; Mon, 4 Sep 2023 19:51:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235202AbjIDTvT (ORCPT ); Mon, 4 Sep 2023 15:51:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232070AbjIDTvS (ORCPT ); Mon, 4 Sep 2023 15:51:18 -0400 Received: from mail-lj1-x231.google.com (mail-lj1-x231.google.com [IPv6:2a00:1450:4864:20::231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF7EAE8; Mon, 4 Sep 2023 12:51:14 -0700 (PDT) Received: by mail-lj1-x231.google.com with SMTP id 38308e7fff4ca-2bceb02fd2bso25939651fa.1; Mon, 04 Sep 2023 12:51:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693857073; x=1694461873; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=3AUBpdzY9yVap/s/23ZdGK7PcPt7+ENwXsRxdz18Anc=; b=CQNoe/vNH7E1XrlGGEfUcjEQB5T4a0HQ0J3tRxOqIk38NWpgotTEqO7M1NrJXG37Hy hXZy31IlbXM1LGSjkjV2T6g6aqPVv/yJYCgc6wfNgtYA5gaAxrgJZ+k/xrb3U4ZzLe7u hHT0S98VEyE/rybSV+Jt8xYRfmS6J0mlODbSfKPwDFUGb68AXONz1CNV8pCJ4cHFn0Qc K+K4RzIffRh6CofUsH8UJrt/nEXmj6dym7BmkxZeevBo0n0n5jD0os9W2LyePp53nFWQ TRVBCzQB1HgPbE7CHqkCyZze1BfCIOUCRO0tOkCvMY+pDdOzQqgDvsMOE93r78mi9hAR ta3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693857073; x=1694461873; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=3AUBpdzY9yVap/s/23ZdGK7PcPt7+ENwXsRxdz18Anc=; b=PPBVdry8RWgEFj2ivwWHF9giZzGz6pb8FbSfJsV+v9p5uBZkI+zjujsjfaxHg6EZIS gzHMx5i00dxxtHKCNkiB1qTpAxnqCjiIi5mhjcT/mg64DXD8nqter+GXuAKKQ6kBHdu7 /0c9SheadrfUa4XN9ZQX9MtYkDWuaEINFMSYCH8JPKMyeoyNk2Du0Ghbcaj2DxIMs0Dq aMiwi5aHp3Ea7kjxfHmdCspa1OYvD0CVNTo2Wz1kFIq9Qng0pdtDKMBON7A3aUWVohxm 2TO+GSNEp92nGTdAE/chdsaqAzNQmIuaK7wt1PNK4hxMnLVYSeCqi+Rw6RqMWBDBbcNh 8n+w== X-Gm-Message-State: AOJu0YyNn1U/jjEIF1/BR9pvib0FIm8ELSVcEw5n2GIOmcyLUZNWSDGS w+Yp/BJrYW4XM2Et6UPDn0I3B0488Hcmzg== X-Google-Smtp-Source: AGHT+IEe5hqM2tLSPD19i5CtW5J/dyVWXpmEWt1LF6g64hsvkH9kl2jvCYwAFLOu+VdQnzFX3w1cLA== X-Received: by 2002:a19:ca12:0:b0:500:dc8d:c344 with SMTP id a18-20020a19ca12000000b00500dc8dc344mr6345801lfg.48.1693857072696; Mon, 04 Sep 2023 12:51:12 -0700 (PDT) Received: from krava ([83.240.60.62]) by smtp.gmail.com with ESMTPSA id qc8-20020a170906d8a800b0099275c59bc9sm6560549ejb.33.2023.09.04.12.51.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Sep 2023 12:51:12 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Mon, 4 Sep 2023 21:51:10 +0200 To: Rong Tao Cc: olsajiri@gmail.com, andrii@kernel.org, daniel@iogearbox.net, sdf@google.com, Rong Tao , Alexei Starovoitov , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Mykola Lysenko , Shuah Khan , Maxime Coquelin , Alexandre Torgue , Yafang Shao , "open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)" , open list , "open list:KERNEL SELFTEST FRAMEWORK" , "moderated list:ARM/STM32 ARCHITECTURE" , "moderated list:ARM/STM32 ARCHITECTURE" Subject: Re: [PATCH bpf-next v10 1/2] selftests/bpf: trace_helpers.c: optimize kallsyms cache Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 04, 2023 at 09:01:20AM +0800, Rong Tao wrote: > From: Rong Tao > > Static ksyms often have problems because the number of symbols exceeds the > MAX_SYMS limit. Like changing the MAX_SYMS from 300000 to 400000 in > commit e76a014334a6("selftests/bpf: Bump and validate MAX_SYMS") solves > the problem somewhat, but it's not the perfect way. > > This commit uses dynamic memory allocation, which completely solves the > problem caused by the limitation of the number of kallsyms. At the same > time, add APIs: > > load_kallsyms_local() > ksym_search_local() > ksym_get_addr_local() missing free_kallsyms_local > diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > index 9d768e083714..13e618317c8b 100644 > --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > @@ -302,16 +302,18 @@ void test_fill_link_info(void) > { > struct test_fill_link_info *skel; > int i; > + struct ksyms *ksyms; > > skel = test_fill_link_info__open_and_load(); > if (!ASSERT_OK_PTR(skel, "skel_open")) > return; > > /* load kallsyms to compare the addr */ > - if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh")) > + ksyms = load_kallsyms_local(); > + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local")) > goto cleanup; actually I don't see why this test should need refreshed kallsyms, it doesn't load/unload testmod, I think it can use global ksyms > > - kprobe_addr = ksym_get_addr(KPROBE_FUNC); > + kprobe_addr = ksym_get_addr_local(ksyms, KPROBE_FUNC); > if (test__start_subtest("kprobe_link_info")) > test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false); > if (test__start_subtest("kretprobe_link_info")) > @@ -329,7 +331,7 @@ void test_fill_link_info(void) > > qsort(kmulti_syms, KMULTI_CNT, sizeof(kmulti_syms[0]), symbols_cmp_r); > for (i = 0; i < KMULTI_CNT; i++) > - kmulti_addrs[i] = ksym_get_addr(kmulti_syms[i]); > + kmulti_addrs[i] = ksym_get_addr_local(ksyms, kmulti_syms[i]); > if (test__start_subtest("kprobe_multi_link_info")) > test_kprobe_multi_fill_link_info(skel, false, false); > if (test__start_subtest("kretprobe_multi_link_info")) > @@ -339,4 +341,5 @@ void test_fill_link_info(void) > > cleanup: > test_fill_link_info__destroy(skel); > + free_kallsyms_local(ksyms); > } > diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c > index 1fbe7e4ac00a..532b05ae2da4 100644 > --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c > +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_testmod_test.c > @@ -4,6 +4,8 @@ > #include "trace_helpers.h" > #include "bpf/libbpf_internal.h" > > +static struct ksyms *ksyms; > + > static void kprobe_multi_testmod_check(struct kprobe_multi *skel) > { > ASSERT_EQ(skel->bss->kprobe_testmod_test1_result, 1, "kprobe_test1_result"); > @@ -50,12 +52,12 @@ static void test_testmod_attach_api_addrs(void) > LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); > unsigned long long addrs[3]; > > - addrs[0] = ksym_get_addr("bpf_testmod_fentry_test1"); > - ASSERT_NEQ(addrs[0], 0, "ksym_get_addr"); > - addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2"); > - ASSERT_NEQ(addrs[1], 0, "ksym_get_addr"); > - addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3"); > - ASSERT_NEQ(addrs[2], 0, "ksym_get_addr"); > + addrs[0] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test1"); > + ASSERT_NEQ(addrs[0], 0, "ksym_get_addr_local"); > + addrs[1] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test2"); > + ASSERT_NEQ(addrs[1], 0, "ksym_get_addr_local"); > + addrs[2] = ksym_get_addr_local(ksyms, "bpf_testmod_fentry_test3"); > + ASSERT_NEQ(addrs[2], 0, "ksym_get_addr_local"); > > opts.addrs = (const unsigned long *) addrs; > opts.cnt = ARRAY_SIZE(addrs); > @@ -79,11 +81,19 @@ static void test_testmod_attach_api_syms(void) > > void serial_test_kprobe_multi_testmod_test(void) > { > - if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh")) > + ksyms = load_kallsyms_local(); > + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local")) > return; > > if (test__start_subtest("testmod_attach_api_syms")) > test_testmod_attach_api_syms(); > + > + ksyms = load_kallsyms_refresh(ksyms); > + if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_refresh")) > + return; hm, this refresh is not needed right? the test got the fresh kallsyms above and both test_testmod_attach_api_syms and test_testmod_attach_api_addrs should be happy > + > if (test__start_subtest("testmod_attach_api_addrs")) > test_testmod_attach_api_addrs(); > + > + free_kallsyms_local(ksyms); > } > diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c > index f83d9f65c65b..d64c4ef336e1 100644 > --- a/tools/testing/selftests/bpf/trace_helpers.c > +++ b/tools/testing/selftests/bpf/trace_helpers.c > @@ -14,104 +14,171 @@ > #include > #include > #include > +#include "bpf/libbpf_internal.h" > > #define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" > #define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" > > -#define MAX_SYMS 400000 > -static struct ksym syms[MAX_SYMS]; > -static int sym_cnt; > +struct ksyms { > + struct ksym *syms; > + size_t sym_cap; > + size_t sym_cnt; > +}; > + > +static struct ksyms *ksyms; > + > +static int ksyms__add_symbol(struct ksyms *ksyms, const char *name, > + unsigned long addr) extra white space in here ^^^ > +{ > + void *tmp; > + > + tmp = strdup(name); > + if (!tmp) > + return -ENOMEM; > + ksyms->syms[ksyms->sym_cnt].addr = addr; > + ksyms->syms[ksyms->sym_cnt].name = tmp; > + > + ksyms->sym_cnt++; > + > + return 0; > +} > + > +void free_kallsyms_local(struct ksyms *ksyms) > +{ > + unsigned int i; > + > + if (!ksyms) > + return; > + > + if (!ksyms->syms) { > + free(ksyms); > + return; > + } > + > + for (i = 0; i < ksyms->sym_cnt; i++) > + free(ksyms->syms[i].name); > + free(ksyms->syms); > + free(ksyms); > +} > > static int ksym_cmp(const void *p1, const void *p2) > { > return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; > } > > -int load_kallsyms_refresh(void) > +struct ksyms *load_kallsyms_refresh(struct ksyms *ksyms) > { > FILE *f; > char func[256], buf[256]; > char symbol; > void *addr; > - int i = 0; > + int ret; > > - sym_cnt = 0; > + /* flush kallsyms, free the previously allocated dynamic memory */ > + free_kallsyms_local(ksyms); > > f = fopen("/proc/kallsyms", "r"); > if (!f) > - return -ENOENT; > + return NULL; > + > + ksyms = calloc(1, sizeof(struct ksyms)); > + if (!ksyms) > + return NULL; I wonder it could be easier not to allocate ksyms, but just let the caller to pass the pointer to 'ksym' variable on stack.. but there might be other problems, so I guess this is fine > > while (fgets(buf, sizeof(buf), f)) { > if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) > break; > if (!addr) > continue; > - if (i >= MAX_SYMS) > - return -EFBIG; > > - syms[i].addr = (long) addr; > - syms[i].name = strdup(func); > - i++; > + ret = libbpf_ensure_mem((void **) &ksyms->syms, &ksyms->sym_cap, > + sizeof(struct ksym), ksyms->sym_cnt + 1); > + if (ret) > + goto error; > + ret = ksyms__add_symbol(ksyms, func, (unsigned long)addr); > + if (ret) > + goto error; > } > fclose(f); > - sym_cnt = i; > - qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); > - return 0; > + qsort(ksyms->syms, ksyms->sym_cnt, sizeof(struct ksym), ksym_cmp); > + return ksyms; > + > +error: > + free_kallsyms_local(ksyms); > + return NULL; > +} > + > +struct ksyms *load_kallsyms_local(void) > +{ > + return load_kallsyms_refresh(NULL); I think we can have just: struct ksyms *load_kallsyms_local(struct ksyms *ksyms); I don't see reason for load_kallsyms_refresh functions, perhaps it's leftover because I don't see the function in the changelog thanks, jirka