[PATCH 7/9] sample/bpf: introduces helpers for percpu array example
From: Ming Lei <tom.leiming@gmail.com>
Date: 2016-01-11 15:57:45
Also in:
lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
This patches introduces helpers for using percpu array. Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- samples/bpf/bpf_helpers.h | 5 +++++ samples/bpf/libbpf.c | 42 ++++++++++++++++++++++++++++++++++++++++++ samples/bpf/libbpf.h | 5 +++++ 3 files changed, 52 insertions(+)
diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h
index 7ad19e1..9996f38 100644
--- a/samples/bpf/bpf_helpers.h
+++ b/samples/bpf/bpf_helpers.h@@ -39,6 +39,11 @@ static int (*bpf_redirect)(int ifindex, int flags) = (void *) BPF_FUNC_redirect; static int (*bpf_perf_event_output)(void *ctx, void *map, int index, void *data, int size) = (void *) BPF_FUNC_perf_event_output; +static void *(*bpf_map_lookup_elem_percpu)(void *map, void *key, unsigned cpu) = + (void *) BPF_FUNC_map_lookup_elem_percpu; +static int (*bpf_map_update_elem_percpu)(void *map, void *key, void *value, + unsigned long long flags, unsigned cpu) = + (void *) BPF_FUNC_map_update_elem_percpu; /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions
diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c
index 65a8d48..2a240c6 100644
--- a/samples/bpf/libbpf.c
+++ b/samples/bpf/libbpf.c@@ -43,6 +43,20 @@ int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags) return syscall(__NR_bpf, BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); } +int bpf_update_elem_percpu(int fd, void *key, void *value, + unsigned long long flags, unsigned cpu) +{ + union bpf_attr attr = { + .map_fd = fd, + .key = ptr_to_u64(key), + .value = ptr_to_u64(value), + .flags = flags, + .cpu = cpu + }; + + return syscall(__NR_bpf, BPF_MAP_UPDATE_ELEM_PERCPU, &attr, sizeof(attr)); +} + int bpf_lookup_elem(int fd, void *key, void *value) { union bpf_attr attr = {
@@ -54,6 +68,34 @@ int bpf_lookup_elem(int fd, void *key, void *value) return syscall(__NR_bpf, BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); } +int bpf_lookup_elem_percpu(int fd, void *key, void *value, unsigned cpu) +{ + union bpf_attr attr = { + .map_fd = fd, + .key = ptr_to_u64(key), + .value = ptr_to_u64(value), + .cpu = cpu, + }; + + return syscall(__NR_bpf, BPF_MAP_LOOKUP_ELEM_PERCPU, &attr, sizeof(attr)); +} + +int bpf_lookup_elem_allcpu(int fd, void *key, void *value_percpu, void *value, + int (*handle_one_cpu)(unsigned, void *, void *)) +{ + unsigned cpu; + int ret; + + for (cpu = 0; cpu < sysconf(_SC_NPROCESSORS_CONF); cpu++) { + ret = bpf_lookup_elem_percpu(fd, key, value_percpu, cpu); + if (!ret) + ret = handle_one_cpu(cpu, value_percpu, value); + if (ret) + return ret; + } + return 0; +} + int bpf_delete_elem(int fd, void *key) { union bpf_attr attr = {
diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h
index 014aacf..e94484d 100644
--- a/samples/bpf/libbpf.h
+++ b/samples/bpf/libbpf.h@@ -8,6 +8,11 @@ int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size, int max_entries); int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags); int bpf_lookup_elem(int fd, void *key, void *value); +int bpf_update_elem_percpu(int fd, void *key, void *value, + unsigned long long flags, unsigned cpu); +int bpf_lookup_elem_percpu(int fd, void *key, void *value, unsigned cpu); +int bpf_lookup_elem_allcpu(int fd, void *key, void *value_percpu, void *value, + int (*handle_one_cpu)(unsigned, void *, void *)); int bpf_delete_elem(int fd, void *key); int bpf_get_next_key(int fd, void *key, void *next_key);
--
1.9.1