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@xxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
include/linux/bpf_verifier.h | 4 ++--
1 file 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 {
--
2.34.1
