From 42c80d3eab15c93e9770396ede17dc5e3bab24d1 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 3 Jul 2009 08:44:07 -0500 Subject: [PATCH 123/279] relay: fix timer madness remove timer calls (!!!) from deep within the tracing infrastructure. This was totally bogus code that can cause lockups and worse. Poll the buffer every 2 jiffies for now. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/relay.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/kernel/relay.c b/kernel/relay.c index a535fc9..c0af3e6 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -340,6 +340,10 @@ static void wakeup_readers(unsigned long data) { struct rchan_buf *buf = (struct rchan_buf *)data; wake_up_interruptible(&buf->read_wait); + /* + * Stupid polling for now: + */ + mod_timer(&buf->timer, jiffies + 1); } /** @@ -357,6 +361,7 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init) init_waitqueue_head(&buf->read_wait); kref_init(&buf->kref); setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf); + mod_timer(&buf->timer, jiffies + 1); } else del_timer_sync(&buf->timer); @@ -739,15 +744,6 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) else buf->early_bytes += buf->chan->subbuf_size - buf->padding[old_subbuf]; - smp_mb(); - if (waitqueue_active(&buf->read_wait)) - /* - * Calling wake_up_interruptible() from here - * will deadlock if we happen to be logging - * from the scheduler (trying to re-grab - * rq->lock), so defer it. - */ - mod_timer(&buf->timer, jiffies + 1); } old = buf->data;