From patchwork Fri Nov 8 06:14:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13867603 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 5C67A1D12ED; Fri, 8 Nov 2024 06:15:02 +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=1731046503; cv=none; b=Vjaap4OlUqWWf/1LWCGU99T563tPX2nUA7bRs2Uf/z78/Kmxe9cGdBxD3LdNI2wzecJMg6BF/GXvnoNUlFXPAfUGHtB73JDT+tJptlhIn1fjcPGPBhi1MYEPveMZILmTJ31+/3fMSQ05v7fkOmpqEKXkBUsta94fPJ/eYW6wJkg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731046503; c=relaxed/simple; bh=rkQClmGRS+TzbbCRqjD51JxsxAOUaefes6WGitXtuAA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KJ9uQ1c3QL84E0jU8qVNeFUiIK8b+AveSWI9m/ikmbNhciavtyMVSeCikDwvQn1wA87RTtQAar+RTqmLUunvljpvVhus9kRwUcOkwx5IxTIrF+IVq5hoBPok7V4yebHaL1VsIl2ffZ7UOXlghP3v4JkJ9o/oUUP0Tr3K+B6ILxs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XQT2roko; 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="XQT2roko" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 348F4C4AF0D; Fri, 8 Nov 2024 06:15:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731046502; bh=rkQClmGRS+TzbbCRqjD51JxsxAOUaefes6WGitXtuAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XQT2rokownISsqEv9wrF4JOHYynqd09XZpJE/Kh6f4cKPsHRx+pXHZ4/V6wWSEW+O fn3tNS8UWRVXnjU/jUEXANMcl6tyfKp+qf5riG1bMpYdkScnpG3dBzRg/pBOmsPhXM 7XVHZNdl9ZztPpbBCEUd9thDO6P3OFJ9/KPPQYF+T+C8z9bmEWf5JKd0GfLpSGXOlr VHyyage1UeIQeWUqRHZ6lg9aiy7Spfp9TA9oBzycB/PiZZA7EIWHzstd5+S0lVIFIC F2pj8dzRpHv3MC2Rt/DJji8fDhu6FHI8pNb5gG64cRFSxfrDvKAsvSx0bKxjEWkh0z HDj35mWgHPU1A== 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 Subject: [PATCH v2 2/4] perf lock contention: Run BPF slab cache iterator Date: Thu, 7 Nov 2024 22:14:57 -0800 Message-ID: <20241108061500.2698340-3-namhyung@kernel.org> X-Mailer: git-send-email 2.47.0.277.g8800431eea-goog In-Reply-To: <20241108061500.2698340-1-namhyung@kernel.org> References: <20241108061500.2698340-1-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. Signed-off-by: Namhyung Kim --- tools/perf/util/bpf_lock_contention.c | 50 +++++++++++++++++++ .../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, 98 insertions(+) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index 41a1ad08789511c3..558590c3111390fc 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..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"); +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 +572,23 @@ int BPF_PROG(end_timestamp) return 0; } +SEC("iter/kmem_cache") +int slab_cache_iter(struct bpf_iter__kmem_cache *ctx) +{ + struct kmem_cache *s = ctx->s; + struct slab_cache_data d; + + if (s == NULL) + return 0; + + d.id = ++slab_cache_id << LCB_F_SLAB_ID_SHIFT; + bpf_probe_read_kernel_str(d.name, sizeof(d.name), s->name); + + 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