diff options
| author | Andrii Nakryiko <andrii@kernel.org> | 2023-12-02 09:56:55 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-12-02 11:36:50 -0800 |
| commit | 45b5623f2d721c25d1a2fdc8c4600fb4b7b61c75 (patch) | |
| tree | f98ea693a0976bed8837a69d895798359b14a2cf /include/linux/bpf_verifier.h | |
| parent | 6685aadcab8f170ae3e4d508989a85c1b8a58dba (diff) | |
| download | linux-45b5623f2d721c25d1a2fdc8c4600fb4b7b61c75.tar.gz linux-45b5623f2d721c25d1a2fdc8c4600fb4b7b61c75.tar.bz2 linux-45b5623f2d721c25d1a2fdc8c4600fb4b7b61c75.zip | |
bpf: rearrange bpf_func_state fields to save a bit of memory
It's a trivial rearrangement saving 8 bytes. We have 4 bytes of padding
at the end which can be filled with another field without increasing
struct bpf_func_state.
copy_func_state() logic remains correct without any further changes.
BEFORE
======
struct bpf_func_state {
struct bpf_reg_state regs[11]; /* 0 1320 */
/* --- cacheline 20 boundary (1280 bytes) was 40 bytes ago --- */
int callsite; /* 1320 4 */
u32 frameno; /* 1324 4 */
u32 subprogno; /* 1328 4 */
u32 async_entry_cnt; /* 1332 4 */
bool in_callback_fn; /* 1336 1 */
/* XXX 7 bytes hole, try to pack */
/* --- cacheline 21 boundary (1344 bytes) --- */
struct tnum callback_ret_range; /* 1344 16 */
bool in_async_callback_fn; /* 1360 1 */
bool in_exception_callback_fn; /* 1361 1 */
/* XXX 2 bytes hole, try to pack */
int acquired_refs; /* 1364 4 */
struct bpf_reference_state * refs; /* 1368 8 */
int allocated_stack; /* 1376 4 */
/* XXX 4 bytes hole, try to pack */
struct bpf_stack_state * stack; /* 1384 8 */
/* size: 1392, cachelines: 22, members: 13 */
/* sum members: 1379, holes: 3, sum holes: 13 */
/* last cacheline: 48 bytes */
};
AFTER
=====
struct bpf_func_state {
struct bpf_reg_state regs[11]; /* 0 1320 */
/* --- cacheline 20 boundary (1280 bytes) was 40 bytes ago --- */
int callsite; /* 1320 4 */
u32 frameno; /* 1324 4 */
u32 subprogno; /* 1328 4 */
u32 async_entry_cnt; /* 1332 4 */
struct tnum callback_ret_range; /* 1336 16 */
/* --- cacheline 21 boundary (1344 bytes) was 8 bytes ago --- */
bool in_callback_fn; /* 1352 1 */
bool in_async_callback_fn; /* 1353 1 */
bool in_exception_callback_fn; /* 1354 1 */
/* XXX 1 byte hole, try to pack */
int acquired_refs; /* 1356 4 */
struct bpf_reference_state * refs; /* 1360 8 */
struct bpf_stack_state * stack; /* 1368 8 */
int allocated_stack; /* 1376 4 */
/* size: 1384, cachelines: 22, members: 13 */
/* sum members: 1379, holes: 1, sum holes: 1 */
/* padding: 4 */
/* last cacheline: 40 bytes */
};
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231202175705.885270-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux/bpf_verifier.h')
| -rw-r--r-- | include/linux/bpf_verifier.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index d99a636d36a7..0c0e1bccad45 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -297,8 +297,8 @@ struct bpf_func_state { * void foo(void) { bpf_timer_set_callback(,foo); } */ u32 async_entry_cnt; - bool in_callback_fn; struct tnum callback_ret_range; + bool in_callback_fn; bool in_async_callback_fn; bool in_exception_callback_fn; /* For callback calling functions that limit number of possible @@ -316,8 +316,8 @@ struct bpf_func_state { /* The following fields should be last. See copy_func_state() */ int acquired_refs; struct bpf_reference_state *refs; - int allocated_stack; struct bpf_stack_state *stack; + int allocated_stack; }; struct bpf_idx_pair { |