diff options
| author | Joanne Koong <joannekoong@fb.com> | 2021-10-29 15:49:08 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-11-01 14:16:03 -0700 |
| commit | 8845b4681bf44b9d2d2badf2c67cf476e42a86bd (patch) | |
| tree | 10e8eb3ffa6127958d7188afa7ba1133197d0029 /include/uapi/linux | |
| parent | 6fdc348006fe2c8f0765f6eecf2e3cbab06c60b5 (diff) | |
bpf: Add alignment padding for "map_extra" + consolidate holes
This patch makes 2 changes regarding alignment padding
for the "map_extra" field.
1) In the kernel header, "map_extra" and "btf_value_type_id"
are rearranged to consolidate the hole.
Before:
struct bpf_map {
...
u32 max_entries; /* 36 4 */
u32 map_flags; /* 40 4 */
/* XXX 4 bytes hole, try to pack */
u64 map_extra; /* 48 8 */
int spin_lock_off; /* 56 4 */
int timer_off; /* 60 4 */
/* --- cacheline 1 boundary (64 bytes) --- */
u32 id; /* 64 4 */
int numa_node; /* 68 4 */
...
bool frozen; /* 117 1 */
/* XXX 10 bytes hole, try to pack */
/* --- cacheline 2 boundary (128 bytes) --- */
...
struct work_struct work; /* 144 72 */
/* --- cacheline 3 boundary (192 bytes) was 24 bytes ago --- */
struct mutex freeze_mutex; /* 216 144 */
/* --- cacheline 5 boundary (320 bytes) was 40 bytes ago --- */
u64 writecnt; /* 360 8 */
/* size: 384, cachelines: 6, members: 26 */
/* sum members: 354, holes: 2, sum holes: 14 */
/* padding: 16 */
/* forced alignments: 2, forced holes: 1, sum forced holes: 10 */
} __attribute__((__aligned__(64)));
After:
struct bpf_map {
...
u32 max_entries; /* 36 4 */
u64 map_extra; /* 40 8 */
u32 map_flags; /* 48 4 */
int spin_lock_off; /* 52 4 */
int timer_off; /* 56 4 */
u32 id; /* 60 4 */
/* --- cacheline 1 boundary (64 bytes) --- */
int numa_node; /* 64 4 */
...
bool frozen /* 113 1 */
/* XXX 14 bytes hole, try to pack */
/* --- cacheline 2 boundary (128 bytes) --- */
...
struct work_struct work; /* 144 72 */
/* --- cacheline 3 boundary (192 bytes) was 24 bytes ago --- */
struct mutex freeze_mutex; /* 216 144 */
/* --- cacheline 5 boundary (320 bytes) was 40 bytes ago --- */
u64 writecnt; /* 360 8 */
/* size: 384, cachelines: 6, members: 26 */
/* sum members: 354, holes: 1, sum holes: 14 */
/* padding: 16 */
/* forced alignments: 2, forced holes: 1, sum forced holes: 14 */
} __attribute__((__aligned__(64)));
2) Add alignment padding to the bpf_map_info struct
More details can be found in commit 36f9814a494a ("bpf: fix uapi hole
for 32 bit compat applications")
Signed-off-by: Joanne Koong <joannekoong@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211029224909.1721024-3-joannekoong@fb.com
Diffstat (limited to 'include/uapi/linux')
| -rw-r--r-- | include/uapi/linux/bpf.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index bd0c9f0487f6..ba5af15e25f5 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5662,6 +5662,7 @@ struct bpf_map_info { __u32 btf_id; __u32 btf_key_type_id; __u32 btf_value_type_id; + __u32 :32; /* alignment pad */ __u64 map_extra; } __attribute__((aligned(8))); |