@@ -260,11 +260,23 @@ int perf_bpf_filter__prepare(struct evsel *evsel, struct target *target)
}
if (needs_pid_hash && geteuid() != 0) {
+ int zero = 0;
+
/* The filters map is shared among other processes */
ret = update_pid_hash(evsel, entry);
if (ret < 0)
goto err;
+ fd = get_pinned_fd("dropped");
+ if (fd < 0) {
+ ret = fd;
+ goto err;
+ }
+
+ /* Reset the lost count */
+ bpf_map_update_elem(fd, &pinned_filter_idx, &zero, BPF_ANY);
+ close(fd);
+
fd = get_pinned_fd("perf_sample_filter");
if (fd < 0) {
ret = fd;
@@ -347,9 +359,25 @@ int perf_bpf_filter__destroy(struct evsel *evsel)
u64 perf_bpf_filter__lost_count(struct evsel *evsel)
{
- struct sample_filter_bpf *skel = evsel->bpf_skel;
+ int count = 0;
+
+ if (list_empty(&evsel->bpf_filters))
+ return 0;
+
+ if (pinned_filter_idx >= 0) {
+ int fd = get_pinned_fd("dropped");
+
+ bpf_map_lookup_elem(fd, &pinned_filter_idx, &count);
+ close(fd);
+ } else if (evsel->bpf_skel) {
+ struct sample_filter_bpf *skel = evsel->bpf_skel;
+ int fd = bpf_map__fd(skel->maps.dropped);
+ int idx = 0;
- return skel ? skel->bss->dropped : 0;
+ bpf_map_lookup_elem(fd, &idx, &count);
+ }
+
+ return count;
}
struct perf_bpf_filter_expr *perf_bpf_filter_expr__new(enum perf_bpf_filter_term term,
@@ -402,6 +430,7 @@ int perf_bpf_filter__pin(void)
/* pinned program will use pid-hash */
bpf_map__set_max_entries(skel->maps.filters, MAX_FILTERS);
bpf_map__set_max_entries(skel->maps.pid_hash, MAX_PIDS);
+ bpf_map__set_max_entries(skel->maps.dropped, MAX_FILTERS);
skel->rodata->use_pid_hash = 1;
if (sample_filter_bpf__load(skel) < 0) {
@@ -459,6 +488,10 @@ int perf_bpf_filter__pin(void)
pr_debug("chmod for pid_hash failed\n");
ret = -errno;
}
+ if (fchmodat(dir_fd, "dropped", 0666, 0) < 0) {
+ pr_debug("chmod for dropped failed\n");
+ ret = -errno;
+ }
err_close:
close(dir_fd);
@@ -23,7 +23,14 @@ struct pid_hash {
__uint(max_entries, 1);
} pid_hash SEC(".maps");
-int dropped;
+/* tgid to filter index */
+struct lost_count {
+ __uint(type, BPF_MAP_TYPE_ARRAY);
+ __type(key, int);
+ __type(value, int);
+ __uint(max_entries, 1);
+} dropped SEC(".maps");
+
volatile const int use_pid_hash;
void *bpf_cast_to_kern_ctx(void *) __ksym;
@@ -189,6 +196,7 @@ int perf_sample_filter(void *ctx)
int in_group = 0;
int group_result = 0;
int i, k;
+ int *losts;
kctx = bpf_cast_to_kern_ctx(ctx);
@@ -252,7 +260,10 @@ int perf_sample_filter(void *ctx)
return 1;
drop:
- __sync_fetch_and_add(&dropped, 1);
+ losts = bpf_map_lookup_elem(&dropped, &k);
+ if (losts != NULL)
+ __sync_fetch_and_add(losts, 1);
+
return 0;
}
As the BPF filter is shared between other processes, it should have its own counter for each invocation. Add a new array map (lost_count) to save the count using the same index as the filter. It should clear the count before running the filter. Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/bpf-filter.c | 37 ++++++++++++++++++-- tools/perf/util/bpf_skel/sample_filter.bpf.c | 15 ++++++-- 2 files changed, 48 insertions(+), 4 deletions(-)