mirror of
https://github.com/netdata/libbpf.git
synced 2026-03-19 07:49:07 +08:00
a0e4e323bb
Add fast variant for x86-64 for now, and we can later extend for others upon demand. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
|
|
#ifndef _TOOLS_LINUX_RING_BUFFER_H_
|
|
#define _TOOLS_LINUX_RING_BUFFER_H_
|
|
|
|
#define READ_ONCE(x) (*(volatile typeof(x) *)&x)
|
|
#define WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v)
|
|
|
|
#define barrier() asm volatile("" ::: "memory")
|
|
|
|
#if defined(__x86_64__)
|
|
# define smp_store_release(p, v) \
|
|
do { \
|
|
barrier(); \
|
|
WRITE_ONCE(*p, v); \
|
|
} while (0)
|
|
|
|
# define smp_load_acquire(p) \
|
|
({ \
|
|
typeof(*p) ___p = READ_ONCE(*p); \
|
|
barrier(); \
|
|
___p; \
|
|
})
|
|
#else
|
|
# define smp_mb() __sync_synchronize()
|
|
|
|
# define smp_store_release(p, v) \
|
|
do { \
|
|
smp_mb(); \
|
|
WRITE_ONCE(*p, v); \
|
|
} while (0)
|
|
|
|
# define smp_load_acquire(p) \
|
|
({ \
|
|
typeof(*p) ___p = READ_ONCE(*p); \
|
|
smp_mb(); \
|
|
___p; \
|
|
})
|
|
#endif /* defined(__x86_64__) */
|
|
|
|
static inline __u64 ring_buffer_read_head(struct perf_event_mmap_page *base)
|
|
{
|
|
return smp_load_acquire(&base->data_head);
|
|
}
|
|
|
|
static inline void ring_buffer_write_tail(struct perf_event_mmap_page *base,
|
|
__u64 tail)
|
|
{
|
|
smp_store_release(&base->data_tail, tail);
|
|
}
|
|
|
|
#endif /* _TOOLS_LINUX_RING_BUFFER_H_ */
|