Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-21 Thread Dan Williams
On Tue, Nov 20, 2018 at 1:03 AM Peter Zijlstra wrote: > > On Tue, Nov 20, 2018 at 02:59:32AM +, Williams, Dan J wrote: > > On Mon, 2018-11-19 at 15:43 -0800, Dave Hansen wrote: > > > On 11/19/18 3:19 PM, Dan Williams wrote: > > > > Andy wondered why a path that can sleep was using __flush_tlb_

Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-20 Thread Peter Zijlstra
On Tue, Nov 20, 2018 at 02:59:32AM +, Williams, Dan J wrote: > On Mon, 2018-11-19 at 15:43 -0800, Dave Hansen wrote: > > On 11/19/18 3:19 PM, Dan Williams wrote: > > > Andy wondered why a path that can sleep was using __flush_tlb_all() > > > [1] > > > and Dave confirmed the expectation for TLB

Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-20 Thread Peter Zijlstra
On Mon, Nov 19, 2018 at 03:19:04PM -0800, Dan Williams wrote: > [1]: https://lore.kernel.org/patchwork/patch/1009434/#1193941 > [2]: https://lore.kernel.org/patchwork/patch/1009434/#1194540 FWIW, that is not the canonical form to refer to emails. Please use: https://lkml.kernel.org/r/$msgid (

Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-19 Thread Williams, Dan J
On Mon, 2018-11-19 at 15:43 -0800, Dave Hansen wrote: > On 11/19/18 3:19 PM, Dan Williams wrote: > > Andy wondered why a path that can sleep was using __flush_tlb_all() > > [1] > > and Dave confirmed the expectation for TLB flush is for modifying / > > invalidating existing pte entries, but not ini

Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-19 Thread Dan Williams
On Mon, Nov 19, 2018 at 3:43 PM Dave Hansen wrote: > > On 11/19/18 3:19 PM, Dan Williams wrote: > > Andy wondered why a path that can sleep was using __flush_tlb_all() [1] > > and Dave confirmed the expectation for TLB flush is for modifying / > > invalidating existing pte entries, but not initial

Re: [PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-19 Thread Dave Hansen
On 11/19/18 3:19 PM, Dan Williams wrote: > Andy wondered why a path that can sleep was using __flush_tlb_all() [1] > and Dave confirmed the expectation for TLB flush is for modifying / > invalidating existing pte entries, but not initial population [2]. I _think_ this is OK. But, could we sprinkl

[PATCH] x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()

2018-11-19 Thread Dan Williams
Commit f77084d96355 "x86/mm/pat: Disable preemption around __flush_tlb_all()" addressed a case where __flush_tlb_all() is called without preemption being disabled. It also left a warning to catch other cases where preemption is not disabled. That warning triggers for the memory hotplug path which i