From nobody Sun Nov 24 15:11:36 2024 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 B5ACC1E2851; Tue, 5 Nov 2024 17:26:40 +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=1730827600; cv=none; b=XmRCSOlnl81h2NsLYrmGJ0orC7QawFa9oE65NU81P+D+hW/HC6jZtU8G/nt2H55uZZDD9CXcdxAMw5LBB/DRSTuJPAVopFRJufr34Xqphl+oLKUuOkfjqOocFlJViWLzeAbEz4OGj/z63iGOJ+hpuO5jwunf70Q3TZ8qlUD1qMA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730827600; c=relaxed/simple; bh=Q7PJcEHIX5DpXW3MulNYQgSzp8YB6bzZUwfUXY/+6Ic=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XcPOTlv2zzXeLod7fTFKsm3bBkorFgOyUC4UoELP3STIm8XTt9c4CzwlR0ZNv3YM5uJoaqgOoAGr6UOQXETCkw+KSlRf/IilGCRZIzE2H71J1OiF0l7/lKD/3CEi6x2EzrUIxT+QjaXbDXGdoOlRUed5ksDm4w/M3x8YXeSFZRI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TBJDSAnk; 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="TBJDSAnk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BADB5C4CED3; Tue, 5 Nov 2024 17:26:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730827600; bh=Q7PJcEHIX5DpXW3MulNYQgSzp8YB6bzZUwfUXY/+6Ic=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TBJDSAnklCnZmD0dVQkFVb1qVFRrVAOQTNb8UyrHxkMPZhF74wAEO5MpQysVpLZ0Q tcH101yUySYf61QfYPOrqxgzxQGcivcgqEfSmhOmH2Cy2f4Rao5+TTtN4BHMI+/5SG fECOdKsRnyzbpuO4rZGYUSxGjgyiH3PA9M9J5K+ZC2xoS8/Umq0J3HNLCYGHL+CjGm h765/Gjv8nq6uQYSBWVM0Zbc/XwWjCbuK7t/i0LTANNb3xsbI7Ooofp+D1ujA3BFXZ ce59Q2oFhGxAfgUda2bR6PRGQ3WhUg++3iDYmgB4r/Yke7P8CvJxuuPVw62fY3Lhwf DTiCnjC7qyhfQ== 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, Song Liu , bpf@vger.kernel.org, Stephane Eranian , Vlastimil Babka , Kees Cook , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com> Subject: [PATCH 2/4] perf lock contention: Run BPF slab cache iterator Date: Tue, 5 Nov 2024 09:26:33 -0800 Message-ID: <20241105172635.2463800-3-namhyung@kernel.org> X-Mailer: git-send-email 2.47.0.199.ga7371fff76-goog In-Reply-To: <20241105172635.2463800-1-namhyung@kernel.org> References: <20241105172635.2463800-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: Namhyung Kim --- tools/perf/util/bpf_lock_contention.c | 51 +++++++++++++++++++ .../perf/util/bpf_skel/lock_contention.bpf.c | 28 ++++++++++ tools/perf/util/bpf_skel/lock_data.h | 12 +++++ tools/perf/util/bpf_skel/vmlinux/vmlinux.h | 8 +++ 4 files changed, 99 insertions(+) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lo= ck_contention.c index 41a1ad08789511c3..a2efd40897bad316 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -12,12 +12,60 @@ #include #include #include +#include #include =20 #include "bpf_skel/lock_contention.skel.h" #include "bpf_skel/lock_data.h" =20 static struct lock_contention_bpf *skel; +static bool has_slab_iter; + +static void check_slab_cache_iter(struct lock_contention *con) +{ + struct btf *btf =3D btf__load_vmlinux_btf(); + s32 ret; + + ret =3D libbpf_get_error(btf); + if (ret) { + pr_debug("BTF loading failed: %d\n", ret); + return; + } + + ret =3D btf__find_by_name_kind(btf, "bpf_iter__kmem_cache", BTF_KIND_STRU= CT); + 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 =3D 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 =3D 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); +} =20 int lock_contention_prepare(struct lock_contention *con) { @@ -109,6 +157,8 @@ int lock_contention_prepare(struct lock_contention *con) skel->rodata->use_cgroup_v2 =3D 1; } =20 + 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 +354,7 @@ static void account_end_timestamp(struct lock_contentio= n *con) =20 int lock_contention_start(void) { + run_slab_cache_iter(); skel->bss->enabled =3D 1; return 0; } diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/ut= il/bpf_skel/lock_contention.bpf.c index 1069bda5d733887f..fd24ccb00faec0ba 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"); =20 +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 =3D -1; =20 __u64 end_ts; =20 +__u32 slab_cache_id; + /* error stat */ int task_fail; int stack_fail; @@ -563,4 +572,23 @@ int BPF_PROG(end_timestamp) return 0; } =20 +SEC("iter/kmem_cache") +int slab_cache_iter(struct bpf_iter__kmem_cache *ctx) +{ + struct kmem_cache *s =3D ctx->s; + struct slab_cache_data d; + + if (s =3D=3D NULL) + return 0; + + d.id =3D ++slab_cache_id << LCB_F_SLAB_ID_SHIFT; + bpf_probe_read_kernel_str(d.name, sizeof(d.name), s->name); + + if (d.id >=3D LCB_F_SLAB_ID_END) + return 0; + + bpf_map_update_elem(&slab_caches, &s, &d, BPF_NOEXIST); + return 0; +} + char LICENSE[] SEC("license") =3D "Dual BSD/GPL"; diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_ske= l/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) =20 +#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 =20 +#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, }; =20 +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/b= pf_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 {}; =20 +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 --=20 2.47.0.199.ga7371fff76-goog