The patch titled
epoll keyed wakeups: teach epoll about hints coming with the wakeup key
has been added to the -mm tree. Its filename is
epoll-keyed-wakeups-v2-teach-epoll-about-hints-coming-with-the-wakeup-key.patch
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------------------------------------------------------
Subject: epoll keyed wakeups: teach epoll about hints coming with the wakeup key
From: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
Use the events hint now sent by some devices, to avoid unnecessary wakeups
for events that are of no interest for the caller. This code handles both
devices that are sending keyed events, and the ones that are not (and
event the ones that sometimes send events, and sometimes don't).
Signed-off-by: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: William Lee Irwin III <wli@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/eventpoll.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff -puN fs/eventpoll.c~epoll-keyed-wakeups-v2-teach-epoll-about-hints-coming-with-the-wakeup-key fs/eventpoll.c
--- a/fs/eventpoll.c~epoll-keyed-wakeups-v2-teach-epoll-about-hints-coming-with-the-wakeup-key
+++ a/fs/eventpoll.c
@@ -372,7 +372,8 @@ static int ep_call_nested(struct nested_
static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests)
{
- wake_up_nested((wait_queue_head_t *) cookie, 1 + call_nests);
+ wake_up_nested_poll((wait_queue_head_t *) cookie, POLLIN,
+ 1 + call_nests);
return 0;
}
@@ -785,6 +786,15 @@ static int ep_poll_callback(wait_queue_t
if (!(epi->event.events & ~EP_PRIVATE_BITS))
goto out_unlock;
+ /*
+ * Check the events coming with the callback. At this stage, not
+ * every device reports the events in the "key" parameter of the
+ * callback. We need to be able to handle both cases here, hence the
+ * test for "key" != NULL before the event match test.
+ */
+ if (key && !((unsigned long) key & epi->event.events))
+ goto out_unlock;
+
/*
* If we are trasfering events to userspace, we can hold no locks
* (because we're accessing user memory, and because of linux f_op->poll()
@@ -1260,7 +1270,6 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, in
case EPOLL_CTL_ADD:
if (!epi) {
epds.events |= POLLERR | POLLHUP;
-
error = ep_insert(ep, &epds, tfile, fd);
} else
error = -EEXIST;
_
Patches currently in -mm which might be from davidel@xxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
epoll-fix-own-poll.patch
epoll-fix-epolls-own-poll-update.patch
epoll-remove-debugging-code.patch
epoll-keyed-wakeups-v2-add-__wake_up_locked_key-and-__wake_up_sync_key.patch
epoll-keyed-wakeups-v2-introduce-new-_poll-wakeup-macros.patch
epoll-keyed-wakeups-v2-make-sockets-use-keyed-wakeups.patch
epoll-keyed-wakeups-v2-teach-epoll-about-hints-coming-with-the-wakeup-key.patch
epoll-keyed-wakeups-v2-make-eventfd-use-keyed-wakeups.patch
epoll-keyed-wakeups-v2-make-tty-use-keyed-wakeups.patch
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