#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
+struct start_key {
+ dev_t dev;
+ u32 _pad;
+ sector_t sector;
+};
+
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, long);
__uint(max_entries, 4096);
} my_map SEC(".maps");
-/* 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")
-int bpf_prog1(struct pt_regs *ctx)
+/* from /sys/kernel/tracing/events/block/block_io_start/format */
+SEC("tracepoint/block/block_io_start")
+int bpf_prog1(struct trace_event_raw_block_rq *ctx)
{
- long rq = PT_REGS_PARM1(ctx);
u64 val = bpf_ktime_get_ns();
+ struct start_key key = {
+ .dev = ctx->dev,
+ .sector = ctx->sector
+ };
- bpf_map_update_elem(&my_map, &rq, &val, BPF_ANY);
+ bpf_map_update_elem(&my_map, &key, &val, BPF_ANY);
return 0;
}
__uint(max_entries, SLOTS);
} lat_map SEC(".maps");
-SEC("kprobe/__blk_account_io_done")
-int bpf_prog2(struct pt_regs *ctx)
+/* from /sys/kernel/tracing/events/block/block_io_done/format */
+SEC("tracepoint/block/block_io_done")
+int bpf_prog2(struct trace_event_raw_block_rq *ctx)
{
- long rq = PT_REGS_PARM1(ctx);
+ struct start_key key = {
+ .dev = ctx->dev,
+ .sector = ctx->sector
+ };
+
u64 *value, l, base;
u32 index;
- value = bpf_map_lookup_elem(&my_map, &rq);
+ value = bpf_map_lookup_elem(&my_map, &key);
if (!value)
return 0;
u64 cur_time = bpf_ktime_get_ns();
u64 delta = cur_time - *value;
- bpf_map_delete_elem(&my_map, &rq);
+ bpf_map_delete_elem(&my_map, &key);
/* the lines below are computing index = log10(delta)*10
* using integer arithmetic