void
NightWatch_sampling(void *p, size_t size, int type,
void *alloc_context)
{
struct alloc_context *context, *ctx_snapshot;
struct memory_chunk *chunk;
ctx_snapshot = (struct alloc_context*)alloc_context;
if (likely(ctx_snapshot->map_only_context_flag == MAP_ONLY_CONTEXT)) {
return;
}
context = ctx_snapshot->ctx;
/* chunk level skip */
if (likely(ctx_snapshot->sample_skip > 0
&& ((size < SMALL_MEMORY_CHUNK)
|| (ctx_snapshot->last_chunk_sz == size
&& size < LARGE_MEMORY_CHUNK)))) {
fetch_and_sub(&context->sample_skip, 1);
set_extend_info(p, NULL);
#ifdef PREDICTOR_INFO
printf("skipping a chunk, size=%d context=%lu\n",
(int)size, context->idx);
#endif /* PREDICTOR_INFO */
return;
}
// assert(size >= SMALL_MEMORY_CHUNK);
#ifdef PREDICTOR_INFO
printf("monitoring a chunk, size=%d context=%lu\n",
(int)size, context->idx);
#endif /* PREDICTOR_INFO */
chunk = alloc_and_init_chunk(p, size, type, context);
set_extend_info(p, chunk);
utl_spin_lock(&context->lock);
list_add(&chunk->sibling, &context->chunk);
chunk->mr = get_predict_mr(context);
if (context->last_chunk_sz != size) {
context->skip_interval = 0;
context->predict_type[0] = UNKNOWN_MAPPING;
context->predict_mr[0] = -1;
}
if (unlikely(context->sample_skip <= 0
&& size < LARGE_MEMORY_CHUNK)) {
context->sample_skip = context->skip_interval;
}
context->last_chunk_sz = size;
utl_spin_unlock(&context->lock);
monit_chunk(chunk);
}
int ring_queue_pop(ring_queue_t *queue, void **ele)
{
if (!(queue->num > 0))
return -1;
int cur_head_index = queue->head;
char * cur_head_flag_index = queue->flags + cur_head_index;
while (!compare_and_swap(cur_head_flag_index, 2, 3))
{
cur_head_index = queue->head;
cur_head_flag_index = queue->flags + cur_head_index;
}
int update_head_index = (cur_head_index + 1) % queue->size;
compare_and_swap(&queue->head, cur_head_index, update_head_index);
*ele = *(queue->data + cur_head_index);
fetch_and_sub(cur_head_flag_index, 3);
fetch_and_sub(&queue->num, 1);
return 0;
}
