Zhang, Xiantao wrote:
From 697d50286088e98da5ac8653c80aaa96c81abf87 Mon Sep 17 00:00:00 2001From: Xiantao Zhang <xiantao.zhang@xxxxxxxxx> Date: Mon, 31 Mar 2008 09:50:24 +0800 Subject: [PATCH] KVM:IA64: Implement smp_call_function_mask for ia64 This function provides more flexible interface for smp infrastructure. Signed-off-by: Xiantao Zhang <xiantao.zhang@xxxxxxxxx>
Hi Xiantao, I'm a little wary of the performance impact of this change. Doing a cpumask compare on all smp_call_function calls seems a little expensive. Maybe it's just noise in the big picture compared to the actual cost of the IPIs, but I thought I'd bring it up. Keep in mind that a cpumask can be fairly big these days, max NR_CPUS is currently 4096. For those booting a kernel with NR_CPUS at 4096 on a dual CPU machine, it would be a bit expensive. Why not keep smp_call_function() the way it was before, rather than implementing it via the call to smp_call_function_mask()? Cheers, Jes -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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