Messages in this thread | | | Subject | Re: [PATCH 06/16] x86/mm/ldt: Reserve high address-space range for the LDT | From | Waiman Long <> | Date | Tue, 16 Jan 2018 12:34:36 -0500 |
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On 01/16/2018 12:31 PM, Peter Zijlstra wrote: > On Tue, Jan 16, 2018 at 06:13:43PM +0100, Joerg Roedel wrote: >> Hi Peter, >> >> On Tue, Jan 16, 2018 at 05:52:13PM +0100, Peter Zijlstra wrote: >>> On Tue, Jan 16, 2018 at 05:36:49PM +0100, Joerg Roedel wrote: >>>> From: Joerg Roedel <jroedel@suse.de> >>>> >>>> Reserve 2MB/4MB of address space for mapping the LDT to >>>> user-space. >>> LDT is 64k, we need 2 per CPU, and NR_CPUS <= 64 on 32bit, that gives >>> 64K*2*64=8M > 2M. >> Thanks, I'll fix that in the next version. > Just lower the max SMP setting until it fits or something. 32bit is too > address space starved for lots of CPU in any case, 64 CPUs on 32bit is > absolutely insane.
Maybe we can just scale the amount of reserved space according to the current NR_CPUS setting. In this way, we won't waste more memory than is necessary.
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