fix(bpf): cleanup initialising structs and nested ifs #1444
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This commit changes all declarae and then initialise code of form below
```
struct foobar x;
x.a = a;
x.b = b;
```
to
```
struct foobar x = { .a = a, .b = b, };
```
The difference in the code produced is as follows
```
; new_pid_key.pid = cur_pid; | pid_time_t new_pid_key = {.pid = cur_pid };
0: 63 6a fc ff 00 00 00 00 *(u32 *)(r10 - 0x4) = r6 | 0: 79 a1 68 ff 00 00 00 00 r1 = *(u64 *)(r10 - 0x98)
1: bf a2 00 00 00 00 00 00 r2 = r10 | 1: 63 1a fc ff 00 00 00 00 *(u32 *)(r10 - 0x4) = r1
2: 07 02 00 00 fc ff ff ff r2 += -0x4 | 2: bf a2 00 00 00 00 00 00 r2 = r10
3: bf a3 00 00 00 00 00 00 r3 = r10 | 3: 07 02 00 00 f0 ff ff ff r2 += -0x10
4: 07 03 00 00 70 ff ff ff r3 += -0x90
```
Modifies calc_delta to remove unnecessary pointer deferencing of second
arg - `val`
Signed-off-by: Sunil Thaha <sthaha@redhat.com>
(cherry picked from commit ac43e26)
sthaha
commented
May 17, 2024
| bpf_map_update_elem(&pid_time, &new_pid_key, &cur_ts, BPF_NOEXIST); | ||
| return cpu_time; | ||
| } | ||
|
|
||
| static inline u64 calc_delta(u64 *prev_val, u64 *val) | ||
| static inline u64 calc_delta(u64 *prev_val, u64 val) |
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note that the current implementation already assumes u64 *val is not nil.
There was a problem hiding this comment.
while you're here wouldn't it be better to make this calc_delta(u64 prev_val, u64 val)?
There was a problem hiding this comment.
IIUC, the original implementation handles prev_val (pointer) being nil/null. The caller may
- calc_delta(nil, 20) -> 0
- calc_delta(0xABCD (80) , 20) -> 0
- calc_delta(0xABCD (8) , 20) -> 12
So the caller does not worry about previous record being present. Also note, this is inlined.
dave-tucker
approved these changes
May 17, 2024
| bpf_map_update_elem(&pid_time, &new_pid_key, &cur_ts, BPF_NOEXIST); | ||
| return cpu_time; | ||
| } | ||
|
|
||
| static inline u64 calc_delta(u64 *prev_val, u64 *val) | ||
| static inline u64 calc_delta(u64 *prev_val, u64 val) |
There was a problem hiding this comment.
while you're here wouldn't it be better to make this calc_delta(u64 prev_val, u64 val)?
rootfs
approved these changes
May 18, 2024
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This commit changes all declarae and then initialise code of form below
to
The difference in the code produced is as follows
Modifies calc_delta to remove unnecessary pointer deferencing of second arg -
val