lkml.org 
[lkml]   [2003]   [Feb]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: more signal locking bugs?
Linus Torvalds wrote:

>>What about this minimal patch? The performance critical operation is
>>signal delivery - we should fix the synchronization between signal
>>delivery and exec first.
>>
>>
>
>The patch looks ok, although I'd also remove the locking and testing from
>collect_sigign_sigcatch() once it is done at a higher level.
>
>And yeah, what about signal delivery? Put back the same lock there?
>
>
I don't know.
Taking read_lock(&tasklist_lock) for send_specific_sig_info might hurt
scalability. Ingo?

If we do not want a global lock, then we have two options:
- make task_lock an interrupt spinlock.
- add a second spinlock to the task structure, for the signal stuff.

Design question - what's worse? Memory bloat or a few additional
local_irq_{en,dis}able().
I don't care - no performance critical codepaths.
Additionally many task_lock()/task_unlock users could be replaced with
spin_unlock_wait(&task->alloc_lock), which would not need the
local_irq_disable().
--
Manfred

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:33    [from the cache]
©2003-2011 Jasper Spaans