Messages in this thread | | | Date | Wed, 29 May 2002 01:27:26 +0530 | From | Dipankar Sarma <> | Subject | Re: 8-CPU (SMP) #s for lockfree rtcache |
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Hi Alan,
In article <1022609447.4123.126.camel@irongate.swansea.linux.org.uk> Alan Cox wrote: > On Tue, 2002-05-28 at 17:34, Andi Kleen wrote: >> And gain tons of new atomic_incs and decs everywhere in the process? >> I would prefer RCU.
> Lots of people write drivers, many of them not SMP kernel locking gurus > who have time to understand RCU and when they can or cannot sleep, and > what happens if their unload is pre-empted and RCU is in use. The kernel > core has to provide a clean easy interface. The network code is a superb > example of this. All the hard thinking is done outside of the driver, at > least unless you choose to join in that thinking to get the last scraps > of performance.
FWIW, recent RCU implementations support preemption. synchronize_kernel() in rcu_poll_preempt patches use call_rcu_preempt() where callbacks wait until all CPUs have done a voluntary context switch. See http://prdownloads.sourceforge.net/lse/rcu_poll_preempt-2.5.14-2.patch
Thanks -- Dipankar Sarma <dipankar@in.ibm.com> http://lse.sourceforge.net Linux Technology Center, IBM Software Lab, Bangalore, India. - 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/
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