From patchwork Fri Dec 20 06:00:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13916274 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81C4C1A3A8A; Fri, 20 Dec 2024 06:00:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674412; cv=none; b=HaxAlejp67rl3zEH+H9fJWimfCnIMD/7e8a4wXRx7FTd/9AQ8ZyoWrFGeJ0/p7c5Vr8vaqh+qasXG4y5KfjtXwm5rylhDgsAtZ4u66ZuW5VvYFP4osd6D7BhM8gUCt0SJDwBjZWsrEh9/9C1NdVF48Wn+r+UV29JHYdDstKjmis= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674412; c=relaxed/simple; bh=KphjkqE7tdLhrmc6I2NBr7SiRf8Q2rvdMP3Dit0D2rY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZLIh+P541cFJvMF9g2z89XwcwIIlLys49V7JSByBgvczAwx14PVAlyQDm44xeAuh+i8vQMJSg0kn76pRIj3SYmiqF3qkquQZ0QMz8DSXuFkpSzqPvRBn2DmPxvdjCkW3B0yCpTBZglpGM+WjnvnEOKeTpkg142GxwLPKhsao8f8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZnrKPND8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZnrKPND8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63C8BC4CEDF; Fri, 20 Dec 2024 06:00:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734674412; bh=KphjkqE7tdLhrmc6I2NBr7SiRf8Q2rvdMP3Dit0D2rY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZnrKPND8n0R9Y3pJP8Dl6gPh7Ttmdzas5tAbPgzwMyi9ZddLb3uR5bnRnuNEkuvXC VKdIm+K4C72Mwzu3pWcxrHqIxbaAvwGHT2onQpwrtHY4pz1syM9oj84Yo3iUydBim7 F+xQBqZMJek0yTtQni4rgCFgGpSYw4tukcvN2Flv5AiPzGAL7LrSmOxXw89AMCTaYD +EImfwfZHQR7Pea4TeDuk0oGho7/LIpWvWuwgjw5AADFSmUHKLAVPLRiFojO4fevuM bzTUOVw4CnvIVYKt7OQ+4DHP9TXd0Q6SApkcdhcPAAinRMFrbPemeLPC20BcGOvDnT b05YWdwdyo5TA== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Andrii Nakryiko , Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , Chun-Tse Shao Subject: [PATCH v3 1/4] perf lock contention: Add and use LCB_F_TYPE_MASK Date: Thu, 19 Dec 2024 22:00:06 -0800 Message-ID: <20241220060009.507297-2-namhyung@kernel.org> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog In-Reply-To: <20241220060009.507297-1-namhyung@kernel.org> References: <20241220060009.507297-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This is a preparation for the later change. It'll use more bits in the flags so let's rename the type part and use the mask to extract the type. Acked-by: Ian Rogers Signed-off-by: Namhyung Kim --- tools/perf/builtin-lock.c | 4 ++-- tools/perf/util/bpf_skel/lock_data.h | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index f66948b1fbed96de..d9f3477d2b02b612 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1490,7 +1490,7 @@ static const struct { static const char *get_type_str(unsigned int flags) { - flags &= LCB_F_MAX_FLAGS - 1; + flags &= LCB_F_TYPE_MASK; for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) { if (lock_type_table[i].flags == flags) @@ -1501,7 +1501,7 @@ static const char *get_type_str(unsigned int flags) static const char *get_type_name(unsigned int flags) { - flags &= LCB_F_MAX_FLAGS - 1; + flags &= LCB_F_TYPE_MASK; for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) { if (lock_type_table[i].flags == flags) diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h index de12892f992f8d43..4f0aae5483745dfa 100644 --- a/tools/perf/util/bpf_skel/lock_data.h +++ b/tools/perf/util/bpf_skel/lock_data.h @@ -32,7 +32,8 @@ struct contention_task_data { #define LCD_F_MMAP_LOCK (1U << 31) #define LCD_F_SIGHAND_LOCK (1U << 30) -#define LCB_F_MAX_FLAGS (1U << 7) +#define LCB_F_TYPE_MAX (1U << 7) +#define LCB_F_TYPE_MASK 0x0000007FU struct contention_data { u64 total_time; From patchwork Fri Dec 20 06:00:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13916275 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67D011A8419; Fri, 20 Dec 2024 06:00:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674413; cv=none; b=sGv4ThvntRxB+FGGW7+xvjjusdEXVkLr9OGslp06upIIAGNjs/WwajoexAN8z3PkCQEd14arBX4ZBIeXsNH+EF4uZKbdoHWThCjqR5jaPyYXYPJPNBvUedA+ZPmUufL65V9+PAwPrmuF1dWI/5ATX8Vx3781Y2UglUNgHu6C/w8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674413; c=relaxed/simple; bh=DciWbf1YOrFnvHGsJrdBvx3igukTjFBexecfLRIhP8E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DT8cbIkEKoLJAxFMheay8s5n71lsR9Pjk1m04XAWV+YydmhvT11qSQcZpkyzKNpiigt/Silss8lQhWDvNA4Bu6X9Mq+akWl+iF8/r1+IQ6/+R2J4o0mF5P3oQO9I3JF4V+q5IkYFKTtLZtH73H2uAKGy8PFsG0gFKXsi3PfRths= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JMLYhe56; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JMLYhe56" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 30B99C4CEE8; Fri, 20 Dec 2024 06:00:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734674412; bh=DciWbf1YOrFnvHGsJrdBvx3igukTjFBexecfLRIhP8E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JMLYhe56DLnky7/VDqgXfcLEqTj8upQSLc5oKi7VGyXpMSWTLaeNACvr0Q3xlEr4v AxMlbNOzUP3LoEQe+2i+urjXTf/iso1f6D+PxY6BaS0HMidK7ShlnkiMBeANN+i23F FSOKJtYJnD47rHThGFOGz2aOTiIbnGv1795gHM5QVN4DEPPfbbVvHA5qVP/fd91PhL wTOQEz3bE3lW6C0ItgT5ygiNyWnb2T1YLobXpcBT0ffLQcolEQG5O5gzSKcHHNejpP BnzLPlKB28amz1ks0OeiljqWKwVX3WjqoQGzVQs7siNK0NlmTF9o+OwkLjqTBz0IDG W+nfTl+osemWw== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Andrii Nakryiko , Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , Chun-Tse Shao Subject: [PATCH v3 2/4] perf lock contention: Run BPF slab cache iterator Date: Thu, 19 Dec 2024 22:00:07 -0800 Message-ID: <20241220060009.507297-3-namhyung@kernel.org> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog In-Reply-To: <20241220060009.507297-1-namhyung@kernel.org> References: <20241220060009.507297-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Recently the kernel got the kmem_cache iterator to traverse metadata of slab objects. This can be used to symbolize dynamic locks in a slab. The new slab_caches hash map will have the pointer of the kmem_cache as a key and save the name and a id. The id will be saved in the flags part of the lock. Acked-by: Ian Rogers Signed-off-by: Namhyung Kim --- tools/perf/util/bpf_lock_contention.c | 50 +++++++++++++++++++ .../perf/util/bpf_skel/lock_contention.bpf.c | 48 ++++++++++++++++++ tools/perf/util/bpf_skel/lock_data.h | 12 +++++ tools/perf/util/bpf_skel/vmlinux/vmlinux.h | 8 +++ 4 files changed, 118 insertions(+) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index 37e17c56f1064e60..169531d1865264be 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -12,12 +12,59 @@ #include #include #include +#include #include #include "bpf_skel/lock_contention.skel.h" #include "bpf_skel/lock_data.h" static struct lock_contention_bpf *skel; +static bool has_slab_iter; + +static void check_slab_cache_iter(struct lock_contention *con) +{ + struct btf *btf = btf__load_vmlinux_btf(); + s32 ret; + + if (btf == NULL) { + pr_debug("BTF loading failed: %s\n", strerror(errno)); + return; + } + + ret = btf__find_by_name_kind(btf, "bpf_iter__kmem_cache", BTF_KIND_STRUCT); + if (ret < 0) { + bpf_program__set_autoload(skel->progs.slab_cache_iter, false); + pr_debug("slab cache iterator is not available: %d\n", ret); + goto out; + } + + has_slab_iter = true; + + bpf_map__set_max_entries(skel->maps.slab_caches, con->map_nr_entries); +out: + btf__free(btf); +} + +static void run_slab_cache_iter(void) +{ + int fd; + char buf[256]; + + if (!has_slab_iter) + return; + + fd = bpf_iter_create(bpf_link__fd(skel->links.slab_cache_iter)); + if (fd < 0) { + pr_debug("cannot create slab cache iter: %d\n", fd); + return; + } + + /* This will run the bpf program */ + while (read(fd, buf, sizeof(buf)) > 0) + continue; + + close(fd); +} int lock_contention_prepare(struct lock_contention *con) { @@ -109,6 +156,8 @@ int lock_contention_prepare(struct lock_contention *con) skel->rodata->use_cgroup_v2 = 1; } + check_slab_cache_iter(con); + if (lock_contention_bpf__load(skel) < 0) { pr_err("Failed to load lock-contention BPF skeleton\n"); return -1; @@ -304,6 +353,7 @@ static void account_end_timestamp(struct lock_contention *con) int lock_contention_start(void) { + run_slab_cache_iter(); skel->bss->enabled = 1; return 0; } diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 1069bda5d733887f..bed446c42561d8bf 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -100,6 +100,13 @@ struct { __uint(max_entries, 1); } cgroup_filter SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(long)); + __uint(value_size, sizeof(struct slab_cache_data)); + __uint(max_entries, 1); +} slab_caches SEC(".maps"); + struct rw_semaphore___old { struct task_struct *owner; } __attribute__((preserve_access_index)); @@ -136,6 +143,8 @@ int perf_subsys_id = -1; __u64 end_ts; +__u32 slab_cache_id; + /* error stat */ int task_fail; int stack_fail; @@ -563,4 +572,43 @@ int BPF_PROG(end_timestamp) return 0; } +/* + * bpf_iter__kmem_cache added recently so old kernels don't have it in the + * vmlinux.h. But we cannot add it here since it will cause a compiler error + * due to redefinition of the struct on later kernels. + * + * So it uses a CO-RE trick to access the member only if it has the type. + * This will support both old and new kernels without compiler errors. + */ +struct bpf_iter__kmem_cache___new { + struct kmem_cache *s; +} __attribute__((preserve_access_index)); + +SEC("iter/kmem_cache") +int slab_cache_iter(void *ctx) +{ + struct kmem_cache *s = NULL; + struct slab_cache_data d; + const char *nameptr; + + if (bpf_core_type_exists(struct bpf_iter__kmem_cache)) { + struct bpf_iter__kmem_cache___new *iter = ctx; + + s = BPF_CORE_READ(iter, s); + } + + if (s == NULL) + return 0; + + nameptr = BPF_CORE_READ(s, name); + bpf_probe_read_kernel_str(d.name, sizeof(d.name), nameptr); + + d.id = ++slab_cache_id << LCB_F_SLAB_ID_SHIFT; + if (d.id >= LCB_F_SLAB_ID_END) + return 0; + + bpf_map_update_elem(&slab_caches, &s, &d, BPF_NOEXIST); + return 0; +} + char LICENSE[] SEC("license") = "Dual BSD/GPL"; diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h index 4f0aae5483745dfa..c15f734d7fc4aecb 100644 --- a/tools/perf/util/bpf_skel/lock_data.h +++ b/tools/perf/util/bpf_skel/lock_data.h @@ -32,9 +32,16 @@ struct contention_task_data { #define LCD_F_MMAP_LOCK (1U << 31) #define LCD_F_SIGHAND_LOCK (1U << 30) +#define LCB_F_SLAB_ID_SHIFT 16 +#define LCB_F_SLAB_ID_START (1U << 16) +#define LCB_F_SLAB_ID_END (1U << 26) +#define LCB_F_SLAB_ID_MASK 0x03FF0000U + #define LCB_F_TYPE_MAX (1U << 7) #define LCB_F_TYPE_MASK 0x0000007FU +#define SLAB_NAME_MAX 28 + struct contention_data { u64 total_time; u64 min_time; @@ -55,4 +62,9 @@ enum lock_class_sym { LOCK_CLASS_RQLOCK, }; +struct slab_cache_data { + u32 id; + char name[SLAB_NAME_MAX]; +}; + #endif /* UTIL_BPF_SKEL_LOCK_DATA_H */ diff --git a/tools/perf/util/bpf_skel/vmlinux/vmlinux.h b/tools/perf/util/bpf_skel/vmlinux/vmlinux.h index 4dcad7b682bdee9c..7b81d3173917fdb5 100644 --- a/tools/perf/util/bpf_skel/vmlinux/vmlinux.h +++ b/tools/perf/util/bpf_skel/vmlinux/vmlinux.h @@ -195,4 +195,12 @@ struct bpf_perf_event_data_kern { */ struct rq {}; +struct kmem_cache { + const char *name; +} __attribute__((preserve_access_index)); + +struct bpf_iter__kmem_cache { + struct kmem_cache *s; +} __attribute__((preserve_access_index)); + #endif // __VMLINUX_H From patchwork Fri Dec 20 06:00:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13916276 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A7011AAA10; Fri, 20 Dec 2024 06:00:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674414; cv=none; b=Jv/zsvRcJoTUoagNHZfszq0Ru3eLXMC3zk89rwHTX6SfFvPyA8y8CEkAkfdrXb2HuRuClHibhnTwzeCk83p3KuHuzjY/4CBqr99eTbIpVK4oCLm3d8crMbU+hJzr8z7FdfNMQNVDY+zdIiGKdXUx3r7AXKCaFwqZju8zKidz/2g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734674414; c=relaxed/simple; bh=6iloHTPlG0e11YnS3/dOhAAf5l/Y4zK8T4R062RqRTU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iLnVagFf2GyYwtuC/xPFJwSmClDHoGDj7QfumxXeHl10ZTyJmNQMWzFo7znS6Lk6uVoSXTt+K/E5LUSaJTz8OXPyLPC5Pwt7IvDE3Gj4yn4p8AhUxqwi6MB3ytF24oKEpHGXGhzVnIAnnwvuKPfrbZ0dqf3K59dRoXOil6eb8fs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KiUtnwmX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KiUtnwmX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 006FDC4CEDF; Fri, 20 Dec 2024 06:00:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734674413; bh=6iloHTPlG0e11YnS3/dOhAAf5l/Y4zK8T4R062RqRTU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KiUtnwmXXBgJZIswxDlgeWOI1JkyFKJNXSjhYBhj5VOh+GsA6EV4E00LlSTLg0PKQ mng7RQMe2kqv92oALEA2oXAyIq7pS6Iuy4bbn1++QImSmqoDwi5u1lOq4u30rSpmaa T3RK6zCt/QqQbLk1+exG1klc16Zv+FN6O/CGvx9ILsZ+7rk3MTIpo1D0ApHDffXKo+ qrHqcf/WnZ0Cf1UX5EyJ/gsfOmHBapsFU1UL0rwUYiEDiHg0kRMPJ32rB5JZYhi1au f1tzLNHUla24Fijl/87cq3JoFDU2mNGj01sWT9+L5cL0rUig+h4BQ00SNB3mAvj5xe fewL7qXFh3dAQ== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Andrii Nakryiko , Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , Chun-Tse Shao Subject: [PATCH v3 3/4] perf lock contention: Resolve slab object name using BPF Date: Thu, 19 Dec 2024 22:00:08 -0800 Message-ID: <20241220060009.507297-4-namhyung@kernel.org> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog In-Reply-To: <20241220060009.507297-1-namhyung@kernel.org> References: <20241220060009.507297-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The bpf_get_kmem_cache() kfunc can return an address of the slab cache (kmem_cache). As it has the name of the slab cache from the iterator, we can use it to symbolize some dynamic kernel locks in a slab. Before: root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl sleep 1 contended total wait max wait avg wait address symbol 2 3.34 us 2.87 us 1.67 us ffff9d7800ad9600 (mutex) 2 2.16 us 1.93 us 1.08 us ffff9d7804b992d8 (mutex) 4 1.37 us 517 ns 343 ns ffff9d78036e6e00 (mutex) 1 1.27 us 1.27 us 1.27 us ffff9d7804b99378 (mutex) 2 845 ns 599 ns 422 ns ffffffff9e1c3620 delayed_uprobe_lock (mutex) 1 845 ns 845 ns 845 ns ffffffff9da0b280 jiffies_lock (spinlock) 2 377 ns 259 ns 188 ns ffffffff9e1cf840 pcpu_alloc_mutex (mutex) 1 305 ns 305 ns 305 ns ffffffff9e1b4cf8 tracepoint_srcu_srcu_usage (mutex) 1 295 ns 295 ns 295 ns ffffffff9e1c0940 pack_mutex (mutex) 1 232 ns 232 ns 232 ns ffff9d7804b7d8d8 (mutex) 1 180 ns 180 ns 180 ns ffffffff9e1b4c28 tracepoint_srcu_srcu_usage (mutex) 1 165 ns 165 ns 165 ns ffffffff9da8b3a0 text_mutex (mutex) After: root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl sleep 1 contended total wait max wait avg wait address symbol 2 1.95 us 1.77 us 975 ns ffff9d5e852d3498 &task_struct (mutex) 1 1.18 us 1.18 us 1.18 us ffff9d5e852d3538 &task_struct (mutex) 4 1.12 us 354 ns 279 ns ffff9d5e841ca800 &kmalloc-cg-512 (mutex) 2 859 ns 617 ns 429 ns ffffffffa41c3620 delayed_uprobe_lock (mutex) 3 691 ns 388 ns 230 ns ffffffffa41c0940 pack_mutex (mutex) 3 421 ns 164 ns 140 ns ffffffffa3a8b3a0 text_mutex (mutex) 1 409 ns 409 ns 409 ns ffffffffa41b4cf8 tracepoint_srcu_srcu_usage (mutex) 2 362 ns 239 ns 181 ns ffffffffa41cf840 pcpu_alloc_mutex (mutex) 1 220 ns 220 ns 220 ns ffff9d5e82b534d8 &signal_cache (mutex) 1 215 ns 215 ns 215 ns ffffffffa41b4c28 tracepoint_srcu_srcu_usage (mutex) Note that the name starts with '&' sign for slab objects to inform they are dynamic locks. It won't give the accurate lock or type names but it's still useful. We may add type info to the slab cache later to get the exact name of the lock in the type later. Acked-by: Ian Rogers Signed-off-by: Namhyung Kim --- tools/perf/util/bpf_lock_contention.c | 52 +++++++++++++++++++ .../perf/util/bpf_skel/lock_contention.bpf.c | 26 +++++++++- 2 files changed, 76 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index 169531d1865264be..a31ace04cb5e7a8f 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -2,6 +2,7 @@ #include "util/cgroup.h" #include "util/debug.h" #include "util/evlist.h" +#include "util/hashmap.h" #include "util/machine.h" #include "util/map.h" #include "util/symbol.h" @@ -20,12 +21,25 @@ static struct lock_contention_bpf *skel; static bool has_slab_iter; +static struct hashmap slab_hash; + +static size_t slab_cache_hash(long key, void *ctx __maybe_unused) +{ + return key; +} + +static bool slab_cache_equal(long key1, long key2, void *ctx __maybe_unused) +{ + return key1 == key2; +} static void check_slab_cache_iter(struct lock_contention *con) { struct btf *btf = btf__load_vmlinux_btf(); s32 ret; + hashmap__init(&slab_hash, slab_cache_hash, slab_cache_equal, /*ctx=*/NULL); + if (btf == NULL) { pr_debug("BTF loading failed: %s\n", strerror(errno)); return; @@ -49,6 +63,7 @@ static void run_slab_cache_iter(void) { int fd; char buf[256]; + long key, *prev_key; if (!has_slab_iter) return; @@ -64,6 +79,34 @@ static void run_slab_cache_iter(void) continue; close(fd); + + /* Read the slab cache map and build a hash with IDs */ + fd = bpf_map__fd(skel->maps.slab_caches); + prev_key = NULL; + while (!bpf_map_get_next_key(fd, prev_key, &key)) { + struct slab_cache_data *data; + + data = malloc(sizeof(*data)); + if (data == NULL) + break; + + if (bpf_map_lookup_elem(fd, &key, data) < 0) + break; + + hashmap__add(&slab_hash, data->id, data); + prev_key = &key; + } +} + +static void exit_slab_cache_iter(void) +{ + struct hashmap_entry *cur; + unsigned bkt; + + hashmap__for_each_entry(&slab_hash, cur, bkt) + free(cur->pvalue); + + hashmap__clear(&slab_hash); } int lock_contention_prepare(struct lock_contention *con) @@ -397,6 +440,7 @@ static const char *lock_contention_get_name(struct lock_contention *con, if (con->aggr_mode == LOCK_AGGR_ADDR) { int lock_fd = bpf_map__fd(skel->maps.lock_syms); + struct slab_cache_data *slab_data; /* per-process locks set upper bits of the flags */ if (flags & LCD_F_MMAP_LOCK) @@ -415,6 +459,12 @@ static const char *lock_contention_get_name(struct lock_contention *con, return "rq_lock"; } + /* look slab_hash for dynamic locks in a slab object */ + if (hashmap__find(&slab_hash, flags & LCB_F_SLAB_ID_MASK, &slab_data)) { + snprintf(name_buf, sizeof(name_buf), "&%s", slab_data->name); + return name_buf; + } + return ""; } @@ -589,5 +639,7 @@ int lock_contention_finish(struct lock_contention *con) cgroup__put(cgrp); } + exit_slab_cache_iter(); + return 0; } diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index bed446c42561d8bf..7182eb559496e34e 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -123,6 +123,8 @@ struct mm_struct___new { struct rw_semaphore mmap_lock; } __attribute__((preserve_access_index)); +extern struct kmem_cache *bpf_get_kmem_cache(u64 addr) __ksym __weak; + /* control flags */ const volatile int has_cpu; const volatile int has_task; @@ -496,8 +498,28 @@ int contention_end(u64 *ctx) }; int err; - if (aggr_mode == LOCK_AGGR_ADDR) - first.flags |= check_lock_type(pelem->lock, pelem->flags); + if (aggr_mode == LOCK_AGGR_ADDR) { + first.flags |= check_lock_type(pelem->lock, + pelem->flags & LCB_F_TYPE_MASK); + + /* Check if it's from a slab object */ + if (bpf_get_kmem_cache) { + struct kmem_cache *s; + struct slab_cache_data *d; + + s = bpf_get_kmem_cache(pelem->lock); + if (s != NULL) { + /* + * Save the ID of the slab cache in the flags + * (instead of full address) to reduce the + * space in the contention_data. + */ + d = bpf_map_lookup_elem(&slab_caches, &s); + if (d != NULL) + first.flags |= d->id; + } + } + } err = bpf_map_update_elem(&lock_stat, &key, &first, BPF_NOEXIST); if (err < 0) { From patchwork Fri Dec 20 06:00:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13916277 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDC361ACECC; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="l0mX5n0D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF8D0C4AF0E; Fri, 20 Dec 2024 06:00:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734674414; bh=uh5tUXshVpXpiclsKqI9+nLz5ONf5ED1fQDla3DobhM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l0mX5n0DNxmK6aBQSBczcweu+cgPi7ZKt/sF0tEsRYhjjqTQ+8df9/tw69j6S6CJ7 mu0XxZrnrlXDfvs1TPAhoEzWePU+9xGo/pYPSiMgSXh9kQ132aBBEoNcILN6vjqvyc GRK0gp1vR27IEUUl+ud0XDel4p1cKHTSLHvZ1ksPM80t7mnoXnaatG8TJRsg2GDaHG b9TqAGbOWKfvBAkJ08bK5kc22UHohYaWXVHNHM6eN6sQqkIkM3jgIpHWWWgc8xTkuI B4ni/A3sJDmClJZx9tw3e/Vj9kKBmH1xNu7lsx5oK6b6Yxp9ibA6/L0pMwDnYsxCaB 7mJyf5zuD7c1Q== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers , Kan Liang Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Andrii Nakryiko , Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , Chun-Tse Shao Subject: [PATCH v3 4/4] perf lock contention: Handle slab objects in -L/--lock-filter option Date: Thu, 19 Dec 2024 22:00:09 -0800 Message-ID: <20241220060009.507297-5-namhyung@kernel.org> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog In-Reply-To: <20241220060009.507297-1-namhyung@kernel.org> References: <20241220060009.507297-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This is to filter lock contention from specific slab objects only. Like in the lock symbol output, we can use '&' prefix to filter slab object names. root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl sleep 1 contended total wait max wait avg wait address symbol 3 14.99 us 14.44 us 5.00 us ffffffff851c0940 pack_mutex (mutex) 2 2.75 us 2.56 us 1.38 us ffff98d7031fb498 &task_struct (mutex) 4 1.42 us 557 ns 355 ns ffff98d706311400 &kmalloc-cg-512 (mutex) 2 953 ns 714 ns 476 ns ffffffff851c3620 delayed_uprobe_lock (mutex) 1 929 ns 929 ns 929 ns ffff98d7031fb538 &task_struct (mutex) 3 561 ns 210 ns 187 ns ffffffff84a8b3a0 text_mutex (mutex) 1 479 ns 479 ns 479 ns ffffffff851b4cf8 tracepoint_srcu_srcu_usage (mutex) 2 320 ns 195 ns 160 ns ffffffff851cf840 pcpu_alloc_mutex (mutex) 1 212 ns 212 ns 212 ns ffff98d7031784d8 &signal_cache (mutex) 1 177 ns 177 ns 177 ns ffffffff851b4c28 tracepoint_srcu_srcu_usage (mutex) With the filter, it can show contentions from the task_struct only. root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -abl -L '&task_struct' sleep 1 contended total wait max wait avg wait address symbol 2 1.97 us 1.71 us 987 ns ffff98d7032fd658 &task_struct (mutex) 1 1.20 us 1.20 us 1.20 us ffff98d7032fd6f8 &task_struct (mutex) It can work with other aggregation mode: root@virtme-ng:/home/namhyung/project/linux# tools/perf/perf lock con -ab -L '&task_struct' sleep 1 contended total wait max wait avg wait type caller 1 25.10 us 25.10 us 25.10 us mutex perf_event_exit_task+0x39 1 21.60 us 21.60 us 21.60 us mutex futex_exit_release+0x21 1 5.56 us 5.56 us 5.56 us mutex futex_exec_release+0x21 Acked-by: Ian Rogers Signed-off-by: Namhyung Kim --- tools/perf/builtin-lock.c | 35 ++++++++++++++++ tools/perf/util/bpf_lock_contention.c | 40 ++++++++++++++++++- .../perf/util/bpf_skel/lock_contention.bpf.c | 21 +++++++++- tools/perf/util/lock-contention.h | 2 + 4 files changed, 95 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index d9f3477d2b02b612..208c482daa56ef93 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -1539,6 +1539,12 @@ static void lock_filter_finish(void) zfree(&filters.cgrps); filters.nr_cgrps = 0; + + for (int i = 0; i < filters.nr_slabs; i++) + free(filters.slabs[i]); + + zfree(&filters.slabs); + filters.nr_slabs = 0; } static void sort_contention_result(void) @@ -2305,6 +2311,27 @@ static bool add_lock_sym(char *name) return true; } +static bool add_lock_slab(char *name) +{ + char **tmp; + char *sym = strdup(name); + + if (sym == NULL) { + pr_err("Memory allocation failure\n"); + return false; + } + + tmp = realloc(filters.slabs, (filters.nr_slabs + 1) * sizeof(*filters.slabs)); + if (tmp == NULL) { + pr_err("Memory allocation failure\n"); + return false; + } + + tmp[filters.nr_slabs++] = sym; + filters.slabs = tmp; + return true; +} + static int parse_lock_addr(const struct option *opt __maybe_unused, const char *str, int unset __maybe_unused) { @@ -2328,6 +2355,14 @@ static int parse_lock_addr(const struct option *opt __maybe_unused, const char * continue; } + if (*tok == '&') { + if (!add_lock_slab(tok + 1)) { + ret = -1; + break; + } + continue; + } + /* * At this moment, we don't have kernel symbols. Save the symbols * in a separate list and resolve them to addresses later. diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index a31ace04cb5e7a8f..fc8666222399c995 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -112,7 +112,7 @@ static void exit_slab_cache_iter(void) int lock_contention_prepare(struct lock_contention *con) { int i, fd; - int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1, ncgrps = 1; + int ncpus = 1, ntasks = 1, ntypes = 1, naddrs = 1, ncgrps = 1, nslabs = 1; struct evlist *evlist = con->evlist; struct target *target = con->target; @@ -201,6 +201,13 @@ int lock_contention_prepare(struct lock_contention *con) check_slab_cache_iter(con); + if (con->filters->nr_slabs && has_slab_iter) { + skel->rodata->has_slab = 1; + nslabs = con->filters->nr_slabs; + } + + bpf_map__set_max_entries(skel->maps.slab_filter, nslabs); + if (lock_contention_bpf__load(skel) < 0) { pr_err("Failed to load lock-contention BPF skeleton\n"); return -1; @@ -271,6 +278,36 @@ int lock_contention_prepare(struct lock_contention *con) bpf_program__set_autoload(skel->progs.collect_lock_syms, false); lock_contention_bpf__attach(skel); + + /* run the slab iterator after attaching */ + run_slab_cache_iter(); + + if (con->filters->nr_slabs) { + u8 val = 1; + int cache_fd; + long key, *prev_key; + + fd = bpf_map__fd(skel->maps.slab_filter); + + /* Read the slab cache map and build a hash with its address */ + cache_fd = bpf_map__fd(skel->maps.slab_caches); + prev_key = NULL; + while (!bpf_map_get_next_key(cache_fd, prev_key, &key)) { + struct slab_cache_data data; + + if (bpf_map_lookup_elem(cache_fd, &key, &data) < 0) + break; + + for (i = 0; i < con->filters->nr_slabs; i++) { + if (!strcmp(con->filters->slabs[i], data.name)) { + bpf_map_update_elem(fd, &key, &val, BPF_ANY); + break; + } + } + prev_key = &key; + } + } + return 0; } @@ -396,7 +433,6 @@ static void account_end_timestamp(struct lock_contention *con) int lock_contention_start(void) { - run_slab_cache_iter(); skel->bss->enabled = 1; return 0; } diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 7182eb559496e34e..6c771ef751d83b43 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -100,6 +100,13 @@ struct { __uint(max_entries, 1); } cgroup_filter SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(key_size, sizeof(long)); + __uint(value_size, sizeof(__u8)); + __uint(max_entries, 1); +} slab_filter SEC(".maps"); + struct { __uint(type, BPF_MAP_TYPE_HASH); __uint(key_size, sizeof(long)); @@ -131,6 +138,7 @@ const volatile int has_task; const volatile int has_type; const volatile int has_addr; const volatile int has_cgroup; +const volatile int has_slab; const volatile int needs_callstack; const volatile int stack_skip; const volatile int lock_owner; @@ -213,7 +221,7 @@ static inline int can_record(u64 *ctx) __u64 addr = ctx[0]; ok = bpf_map_lookup_elem(&addr_filter, &addr); - if (!ok) + if (!ok && !has_slab) return 0; } @@ -226,6 +234,17 @@ static inline int can_record(u64 *ctx) return 0; } + if (has_slab && bpf_get_kmem_cache) { + __u8 *ok; + __u64 addr = ctx[0]; + long kmem_cache_addr; + + kmem_cache_addr = (long)bpf_get_kmem_cache(addr); + ok = bpf_map_lookup_elem(&slab_filter, &kmem_cache_addr); + if (!ok) + return 0; + } + return 1; } diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h index bd71fb73825aa8e1..a09f7fe877df8184 100644 --- a/tools/perf/util/lock-contention.h +++ b/tools/perf/util/lock-contention.h @@ -10,10 +10,12 @@ struct lock_filter { int nr_addrs; int nr_syms; int nr_cgrps; + int nr_slabs; unsigned int *types; unsigned long *addrs; char **syms; u64 *cgrps; + char **slabs; }; struct lock_stat {