*/
#define _GNU_SOURCE
+#include <assert.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
unsigned int poll_max_size;
+/*
+ * Resize the epoll events structure of the new size.
+ *
+ * Return 0 on success or else -1 with the current events pointer untouched.
+ */
+static int resize_poll_event(struct lttng_poll_event *events,
+ uint32_t new_size)
+{
+ struct epoll_event *ptr;
+
+ assert(events);
+
+ ptr = realloc(events->events, new_size * sizeof(*ptr));
+ if (ptr == NULL) {
+ PERROR("realloc epoll add");
+ goto error;
+ }
+ events->events = ptr;
+ events->alloc_size = new_size;
+
+ return 0;
+
+error:
+ return -1;
+}
+
/*
* Create epoll set and allocate returned events structure.
*/
}
/* Don't bust the limit here */
- if (size > poll_max_size) {
+ if (size > poll_max_size && poll_max_size != 0) {
size = poll_max_size;
}
goto error_close;
}
- events->events_size = size;
+ events->alloc_size = events->init_size = size;
events->nb_fd = 0;
return 0;
*/
int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events)
{
- int ret, new_size;
- struct epoll_event ev, *ptr;
+ int ret;
+ struct epoll_event ev;
if (events == NULL || events->events == NULL || fd < 0) {
ERR("Bad compat epoll add arguments");
events->nb_fd++;
- if (events->nb_fd >= events->events_size) {
- new_size = 2 * events->events_size;
- ptr = realloc(events->events, new_size * sizeof(struct epoll_event));
- if (ptr == NULL) {
- PERROR("realloc epoll add");
- goto error;
- }
- events->events = ptr;
- events->events_size = new_size;
- }
-
end:
return 0;
int compat_epoll_wait(struct lttng_poll_event *events, int timeout)
{
int ret;
+ uint32_t new_size;
- if (events == NULL || events->events == NULL ||
- events->events_size < events->nb_fd) {
+ if (events == NULL || events->events == NULL) {
ERR("Wrong arguments in compat_epoll_wait");
goto error;
}
+ /*
+ * Resize if needed before waiting. We could either expand the array or
+ * shrink it down. It's important to note that after this step, we are
+ * ensured that the events argument of the epoll_wait call will be large
+ * enough to hold every possible returned events.
+ */
+ if (events->nb_fd > events->alloc_size) {
+ /* Expand if the nb_fd is higher than the actual size. */
+ new_size = events->alloc_size << 1UL;
+ } else if ((events->nb_fd << 1UL) <= events->alloc_size &&
+ events->nb_fd >= events->init_size) {
+ /* Shrink if nb_fd multiplied by two is <= than the actual size. */
+ new_size = events->alloc_size >> 1UL;
+ } else {
+ /* Indicate that we don't want to resize. */
+ new_size = 0;
+ }
+
+ if (new_size) {
+ ret = resize_poll_event(events, new_size);
+ if (ret < 0) {
+ /* ENOMEM problem at this point. */
+ goto error;
+ }
+ }
+
do {
ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout);
} while (ret == -1 && errno == EINTR);
goto error;
}
+ /*
+ * Since the returned events are set sequentially in the "events" structure
+ * we only need to return the epoll_wait value and iterate over it.
+ */
return ret;
error:
}
poll_max_size = atoi(buf);
- if (poll_max_size <= 0) {
+ if (poll_max_size == 0) {
/* Extra precaution */
poll_max_size = DEFAULT_POLL_SIZE;
}