Re: robust futex heap support patch
From: david singleton
Date: Sat Nov 26 2005 - 15:51:10 EST
On Nov 26, 2005, at 5:31 AM, Ingo Molnar wrote:
* david singleton <dsingleton@xxxxxxxxxx> wrote:
There is a new patch, patch-2.6.14-rt15-rf1, that adds support for
robust and priority inheriting pthread_mutexes on the 'heap'.
we need to go a bit slower. For now i had to remove robust-futexes from
the -rt17 release because they broke normal (non-robust) futex support
in -rt15. A simple mozilla startup would hang... Please send fixes
against -rt16 and i'll try to re-add the robust futexes patch later on.
You can find -rt16 at:
whoops, sorry.
Here's he piece that broke regular futexes. Futex wake doesn't
need to check to see if the robust list is null or not.
Index: linux-2.6.14/kernel/futex.c
===================================================================
--- linux-2.6.14.orig/kernel/futex.c
+++ linux-2.6.14/kernel/futex.c
@@ -323,10 +323,6 @@ static int futex_wake(unsigned long uadd
ret = get_futex_key(uaddr, &key, &head, &sem);
if (unlikely(ret != 0))
goto out;
- if (head == NULL) {
- ret = -EINVAL;
- goto out;
- }
bh = hash_futex(&key);
spin_lock(&bh->lock);
Let me get the build fixed and add a new test for myself. I'll start
running
this on my desktop to do builds, run mozilla and firefox, and generally
do all my normal work.
David
http://people.redhat.com/mingo/realtime-preempt/older/patch-2.6.14-
rt16
The previous patches only supported either file based pthread_mutexes
or mmapped anonymous memory based pthread_mutexes. This patch allows
pthread_mutexes to be 'malloc'ed while using the
PTHREAD_MUTEX_ROBUST_NP attribute or PTHREAD_PRIO_INHERIT attribute.
The patch can be found at:
http://source.mvista.com/~dsingleton
this patch looks much cleaner than the earlier one, but there's one
more
step to go: now that we've got the futex_head in every vma, why not
hang
all robust futexes to the vma, and thus get rid of ->robust_list and
->robust_sem from struct address_space?
Ingo
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