Messages in this thread |  | | | Date | Sun, 5 Mar 2006 00:45:34 -0800 | | From | Andrew Morton <> | | Subject | Re: [PATCH 8/8] [I/OAT] TCP recv offload to I/OAT |
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Chris Leech <christopher.leech@intel.com> wrote: > > +#ifdef CONFIG_NET_DMA > + tp->ucopy.dma_chan = NULL; > + if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) && !sysctl_tcp_low_latency && __get_cpu_var(softnet_data.net_dma)) > + dma_lock_iovec_pages(msg->msg_iov, len, &tp->ucopy.locked_list); > +#endif
The __get_cpu_var() here will run smp_processor_id() from preemptible context. You'll get a big warning if the correct debug options are set.
The reason for this is that preemption could cause this code to hop between CPUs.
Please always test code with all debug options enabled and with full kernel preemption.
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