Messages in this thread | | | Date | Tue, 9 Jan 2007 10:34:17 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH] flush_cpu_workqueue: don't flush an empty ->worklist |
| |
On Mon, Jan 08, 2007 at 03:54:28PM -0800, Andrew Morton wrote: > Furthermore I don't know which of these need to be tossed overboard if/when > we get around to using the task freezer for CPU hotplug synchronisation. > Hopefully, a lot of them. I don't really understand why we're continuing > to struggle with the existing approach before that question is settled.
Good point!
Fundamentally, I think we need to answer this question:
"Do we provide *some* mechanism to block concurrent hotplug operations from happening? By hotplug operations I mean both changes to the bitmap and execution of all baclbacks in CPU_DEAD/ONLINE etc"
If NO, then IMHO we will be forever fixing races
If YES, then what is that mechanism? freeze_processes()? or a magical lock?
freeze_processes() cant be that mechanism, if my understanding of it is correct - see http://lkml.org/lkml/2007/1/8/149 and http://marc.theaimsgroup.com/?l=linux-kernel&m=116817460726058.
I would be happy to be corrected if the above impression of freeze_processes() is corrected ..
-- Regards, vatsa - 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/
| |