Brian Behlendorf d4899f4747 kmem-cache: Fix slab ageing soft lockup ... Commit a10287e00d slightly reworked the slab ageing code such that it is no longer dependent on the Linux delayed work queue interfaces. This was good for portability and performance, but it requires us to use the on_each_cpu() function to execute the spl_magazine_age() function. That means that the function is now executing in interrupt context whereas before it was scheduled in normal process context. And that means we need to be slightly more careful about the locking in the interrupt handler. With the reworked code it's possible that we'll be holding the skc->skc_lock and be interrupted to handle the spl_magazine_age() IRQ. This will result in a deadlock and soft lockup errors unless we're careful to detect the contention and avoid taking the lock in the interupt handler. So that's what this patch does. Alternately, (and slightly more conventionally) we could have used spin_lock_irqsave() to prevent this race entirely but I'd perfer to avoid disabling interrupts as much as possible due to performance concerns. There is absolutely no penalty for us not aging objects out of the magazine due to contention. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Prakash Surya <surya1@llnl.gov> Closes zfsonlinux/zfs#1193		2013-01-14 10:07:58 -08:00
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spl	kmem-cache: Fix slab ageing soft lockup	2013-01-14 10:07:58 -08:00
splat	call_usermodehelper() should wait for process	2013-01-09 16:54:19 -08:00
.gitignore	Remove Makefile from non-toplevel .gitignore files	2012-08-23 12:49:04 -07:00
Makefile.in	Add script for builtin module building.	2012-07-26 15:13:09 -07:00