@@ -2183,6 +2183,17 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
*/
ep = f.file->private_data;
+ /*
+ * Handle EPOLL_CTL_MIN_WAIT upfront as we don't need to care about
+ * the fd being passed in.
+ */
+ if (op == EPOLL_CTL_MIN_WAIT) {
+ /* return old value */
+ error = ep->min_wait_ts;
+ ep->min_wait_ts = epds->data;
+ goto error_fput;
+ }
+
/* Get the "struct file *" for the target file */
tf = fdget(fd);
if (!tf.file)
@@ -2315,7 +2326,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
{
struct epoll_event epds;
- if (ep_op_has_event(op) &&
+ if ((ep_op_has_event(op) || op == EPOLL_CTL_MIN_WAIT) &&
copy_from_user(&epds, event, sizeof(struct epoll_event)))
return -EFAULT;
@@ -59,7 +59,7 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
static inline int ep_op_has_event(int op)
{
- return op != EPOLL_CTL_DEL;
+ return op != EPOLL_CTL_DEL && op != EPOLL_CTL_MIN_WAIT;
}
#else
@@ -26,6 +26,7 @@
#define EPOLL_CTL_ADD 1
#define EPOLL_CTL_DEL 2
#define EPOLL_CTL_MOD 3
+#define EPOLL_CTL_MIN_WAIT 4
/* Epoll event masks */
#define EPOLLIN (__force __poll_t)0x00000001
Add support for EPOLL_CTL_MIN_WAIT, which can be used to define a minimum reap time for an epoll context. Basic test case: struct d { int p1, p2; }; static void *fn(void *data) { struct d *d = data; char b = 0x89; /* Generate 2 events 20 msec apart */ usleep(10000); write(d->p1, &b, sizeof(b)); usleep(10000); write(d->p2, &b, sizeof(b)); return NULL; } int main(int argc, char *argv[]) { struct epoll_event ev, events[2]; pthread_t thread; int p1[2], p2[2]; struct d d; int efd, ret; efd = epoll_create1(0); if (efd < 0) { perror("epoll_create"); return 1; } if (pipe(p1) < 0) { perror("pipe"); return 1; } if (pipe(p2) < 0) { perror("pipe"); return 1; } ev.events = EPOLLIN; ev.data.fd = p1[0]; if (epoll_ctl(efd, EPOLL_CTL_ADD, p1[0], &ev) < 0) { perror("epoll add"); return 1; } ev.events = EPOLLIN; ev.data.fd = p2[0]; if (epoll_ctl(efd, EPOLL_CTL_ADD, p2[0], &ev) < 0) { perror("epoll add"); return 1; } /* always wait 200 msec for events */ ev.data.u64 = 200000; if (epoll_ctl(efd, EPOLL_CTL_MIN_WAIT, -1, &ev) < 0) { perror("epoll add set timeout"); return 1; } d.p1 = p1[1]; d.p2 = p2[1]; pthread_create(&thread, NULL, fn, &d); /* expect to get 2 events here rather than just 1 */ ret = epoll_wait(efd, events, 2, -1); printf("epoll_wait=%d\n", ret); return 0; } If EPOLL_CTL_MIN_WAIT is used with a timeout of 0, it is a no-op, and acts the same as if it wasn't called to begin with. Only a non-zero usec delay value will result in a wait time being applied for reaping events. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/eventpoll.c | 13 ++++++++++++- include/linux/eventpoll.h | 2 +- include/uapi/linux/eventpoll.h | 1 + 3 files changed, 14 insertions(+), 2 deletions(-)