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authorSong Liu <songliubraving@fb.com>2019-01-17 19:15:15 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-01-21 23:00:57 +0300
commit6ee52e2a3fe4ea35520720736e6791df1fb67106 (patch)
treebe662847ba4bee4b26c755a19b1f257bf59e0370 /kernel/bpf
parentd764ac6464915523e68e220b6aa4c3c2eb8e3f94 (diff)
downloadlinux-6ee52e2a3fe4ea35520720736e6791df1fb67106.tar.xz
perf, bpf: Introduce PERF_RECORD_BPF_EVENT
For better performance analysis of BPF programs, this patch introduces PERF_RECORD_BPF_EVENT, a new perf_event_type that exposes BPF program load/unload information to user space. Each BPF program may contain up to BPF_MAX_SUBPROGS (256) sub programs. The following example shows kernel symbols for a BPF program with 7 sub programs: ffffffffa0257cf9 t bpf_prog_b07ccb89267cf242_F ffffffffa02592e1 t bpf_prog_2dcecc18072623fc_F ffffffffa025b0e9 t bpf_prog_bb7a405ebaec5d5c_F ffffffffa025dd2c t bpf_prog_a7540d4a39ec1fc7_F ffffffffa025fcca t bpf_prog_05762d4ade0e3737_F ffffffffa026108f t bpf_prog_db4bd11e35df90d4_F ffffffffa0263f00 t bpf_prog_89d64e4abf0f0126_F ffffffffa0257cf9 t bpf_prog_ae31629322c4b018__dummy_tracepoi When a bpf program is loaded, PERF_RECORD_KSYMBOL is generated for each of these sub programs. Therefore, PERF_RECORD_BPF_EVENT is not needed for simple profiling. For annotation, user space need to listen to PERF_RECORD_BPF_EVENT and gather more information about these (sub) programs via sys_bpf. Signed-off-by: Song Liu <songliubraving@fb.com> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradeaed.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kernel-team@fb.com Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20190117161521.1341602-4-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/core.c2
-rw-r--r--kernel/bpf/syscall.c2
2 files changed, 3 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index f908b9356025..19c49313c709 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -495,7 +495,7 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog,
*symbol_end = addr + hdr->pages * PAGE_SIZE;
}
-static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
+void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
{
const char *end = sym + KSYM_NAME_LEN;
const struct btf_type *type;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b155cd17c1bd..30ebd085790b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1211,6 +1211,7 @@ static void __bpf_prog_put_rcu(struct rcu_head *rcu)
static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
{
if (atomic_dec_and_test(&prog->aux->refcnt)) {
+ perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
/* bpf_prog_free_id() must be called first */
bpf_prog_free_id(prog, do_idr_lock);
bpf_prog_kallsyms_del_all(prog);
@@ -1554,6 +1555,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
}
bpf_prog_kallsyms_add(prog);
+ perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0);
return err;
free_used_maps: