samples/bpf: update tracex[23] examples to use per-cpu maps

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 25 insertions, 13 deletions

diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c
index b32367cfbff4..09c1adc27d42 100644
--- a/samples/bpf/tracex2_kern.c
+++ b/samples/bpf/tracex2_kern.c
@@ -70,7 +70,7 @@ struct hist_key {
 };
 
 struct bpf_map_def SEC("maps") my_hist_map = {
-        .type = BPF_MAP_TYPE_HASH,
+        .type = BPF_MAP_TYPE_PERCPU_HASH,
         .key_size = sizeof(struct hist_key),
         .value_size = sizeof(long),
         .max_entries = 1024,
diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c
index cd0241c1447a..ab5b19e68acf 100644
--- a/samples/bpf/tracex2_user.c
+++ b/samples/bpf/tracex2_user.c
@@ -37,6 +37,8 @@ struct hist_key {
 static void print_hist_for_pid(int fd, void *task)
 {
         struct hist_key key = {}, next_key;
+        unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+        long values[nr_cpus];
         char starstr[MAX_STARS];
         long value;
         long data[MAX_INDEX] = {};
@@ -49,7 +51,10 @@ static void print_hist_for_pid(int fd, void *task)
                         key = next_key;
                         continue;
                 }
-                bpf_lookup_elem(fd, &next_key, &value);
+                bpf_lookup_elem(fd, &next_key, values);
+                value = 0;
+                for (i = 0; i < nr_cpus; i++)
+                        value += values[i];
                 ind = next_key.index;
                 data[ind] = value;
                 if (value && ind > max_ind)
diff --git a/samples/bpf/tracex3_kern.c b/samples/bpf/tracex3_kern.c
index bf337fbb0947..9974c3d7c18b 100644
--- a/samples/bpf/tracex3_kern.c
+++ b/samples/bpf/tracex3_kern.c
@@ -20,7 +20,7 @@ struct bpf_map_def SEC("maps") my_map = {
 /* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
  * example will no longer be meaningful
  */
-SEC("kprobe/blk_mq_start_request")
+SEC("kprobe/blk_start_request")
 int bpf_prog1(struct pt_regs *ctx)
 {
         long rq = PT_REGS_PARM1(ctx);
@@ -42,13 +42,13 @@ static unsigned int log2l(unsigned long long n)
 #define SLOTS 100
 
 struct bpf_map_def SEC("maps") lat_map = {
-        .type = BPF_MAP_TYPE_ARRAY,
+        .type = BPF_MAP_TYPE_PERCPU_ARRAY,
         .key_size = sizeof(u32),
         .value_size = sizeof(u64),
         .max_entries = SLOTS,
 };
 
-SEC("kprobe/blk_update_request")
+SEC("kprobe/blk_account_io_completion")
 int bpf_prog2(struct pt_regs *ctx)
 {
         long rq = PT_REGS_PARM1(ctx);
@@ -81,7 +81,7 @@ int bpf_prog2(struct pt_regs *ctx)
 
         value = bpf_map_lookup_elem(&lat_map, &index);
         if (value)
-                __sync_fetch_and_add((long *)value, 1);
+                *value += 1;
 
         return 0;
 }
diff --git a/samples/bpf/tracex3_user.c b/samples/bpf/tracex3_user.c
index 0aaa933ab938..48716f7f0d8b 100644
--- a/samples/bpf/tracex3_user.c
+++ b/samples/bpf/tracex3_user.c
@@ -20,11 +20,13 @@
 
 static void clear_stats(int fd)
 {
+        unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+        __u64 values[nr_cpus];
         __u32 key;
-        __u64 value = 0;
 
+        memset(values, 0, sizeof(values));
         for (key = 0; key < SLOTS; key++)
-                bpf_update_elem(fd, &key, &value, BPF_ANY);
+                bpf_update_elem(fd, &key, values, BPF_ANY);
 }
 
 const char *color[] = {
@@ -75,15 +77,20 @@ static void print_banner(void)
 
 static void print_hist(int fd)
 {
-        __u32 key;
-        __u64 value;
-        __u64 cnt[SLOTS];
-        __u64 max_cnt = 0;
+        unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
         __u64 total_events = 0;
+        long values[nr_cpus];
+        __u64 max_cnt = 0;
+        __u64 cnt[SLOTS];
+        __u64 value;
+        __u32 key;
+        int i;
 
         for (key = 0; key < SLOTS; key++) {
+                bpf_lookup_elem(fd, &key, values);
                 value = 0;
-                bpf_lookup_elem(fd, &key, &value);
+                for (i = 0; i < nr_cpus; i++)
+                        value += values[i];
                 cnt[key] = value;
                 total_events += value;
                 if (value > max_cnt)