From c7138f37f905bb7987b1f9f5a8ee73667db39f25 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 24 Mar 2009 13:18:16 +0100 Subject: perf_counter: fix perf_poll() Impact: fix kerneltop 100% CPU usage Only return a poll event when there's actually been one, poll_wait() doesn't actually wait for the waitq you pass it, it only enqueues you on it. Only once all FDs have been iterated and none of thm returned a poll-event will it schedule(). Also make it return POLL_HUP when there's not mmap() area to read from. Further, fix a silly bug in the write code. Reported-by: Mike Galbraith Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Arjan van de Ven Orig-LKML-Reference: <1237897096.24918.181.camel@twins> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/perf_counter.h') diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 2b5e66d5ebdf..48212c15b7d6 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -246,6 +246,7 @@ struct file; struct perf_mmap_data { struct rcu_head rcu_head; int nr_pages; + atomic_t wakeup; atomic_t head; struct perf_counter_mmap_page *user_page; void *data_pages[0]; -- cgit v1.2.2