From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation
Date: Mon, 07 Dec 2015 14:29:53 -0500 (EST)
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From: Thomas Graf <tgraf@suug.ch>
Date: Mon, 7 Dec 2015 16:35:24 +0100

> Did you look into what __vmalloc prevents to work with BH disabled?

You can't issue the cross-cpu TLB flushes from atomic contexts.
It's the kernel page table updates that create the restriction.