Messages in this thread | | | Date | Wed, 29 Jun 2005 10:53:10 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: kmalloc without GFP_xxx? |
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On Wed, 29 Jun 2005, Jörn Engel wrote:
> On Wed, 29 June 2005 17:14:32 +0300, Denis Vlasenko wrote: > > > > This is why I always use _irqsave. Less error prone. > > And locking is a very easy to get 'slightly' wrong, thus > > I trade 0.1% of performance for code simplicity. > > But sometimes you get lucky and trade 100ms latency for code > simplicity. Of course, the audio people don't mind anymore, now that > we have all sorts of realtime patches. Everyone's happy! >
God! If you are holding a spin_lock for 100ms, something is terribly wrong, especialy since you better not schedule holding that spin_lock. Spinlocks are _suppose_ to be for quick things. The difference in latency between a *_lock and *_lock_irqsave only effects UP, on SMP both will give the same latency, since another CPU might be busy spinning while waiting for that lock, heck, on SMP the latency of *_lock can actually be higher, since, as I already said, the other CPU will even have to wait while the CPU that has the lock is servicing interrupts.
Although I must say that with all the realtime patches I'm happy :-)
-- Steve
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