On Mon, 25 Nov 2002, John Myers wrote:
> Davide Libenzi wrote:
>
> >No, look at the code :
> >
> >
> Ok, I completely misread what you wrote. I thought you were suggestiong
> a change to the locking behavior of wake_up() itself.
The problem with the wake_up() is its potential recursion when using the
callback'd version of the wait queue. We can have two scenarios ( given
'->' == CONTAINED-IN ) :
1)
epfd1 -> epfd2 -> ... ->epfdN with N huge
2)
epfd1 -> epfd2 -> ... -> epfd1
Now, when you call wake_up() without using any care you'll blow up the
stack. This should be adressed with the 0.58 version of the patch. Also, I
moved the :
/* Add the current item to the list of active epoll hook for this file */
spin_lock(&tfile->f_ep_lock);
list_add_tail(&epi->fllink, &tfile->f_ep_links);
spin_unlock(&tfile->f_ep_lock);
before inserting the item in the hash, so I don't need to increase the
usage count in ep_insert().
- Davide
-
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This archive was generated by hypermail 2b29 : Sat Nov 30 2002 - 22:00:12 EST