Re: [PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-06 Thread Peter Zijlstra
On Fri, Aug 03, 2018 at 01:39:52PM -0400, Rik van Riel wrote: > > At the very least the Changelog needs to explain why we cannot do > > away with the swizzle now and how doing the swizzle without the > > refcounting is not completely broken (I think I see, but urgh). > > The changelog for patches

Re: [PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-03 Thread Rik van Riel
On Fri, 2018-08-03 at 19:25 +0200, Peter Zijlstra wrote: > On Fri, Aug 03, 2018 at 12:40:48PM -0400, Rik van Riel wrote: > > On Fri, 2018-08-03 at 17:56 +0200, Peter Zijlstra wrote: > > > > > > Why can't we skip the ->active_mm swizzle and keep ->active_mm == > > > ->mm. > > > > > > Doing the swi

Re: [PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-03 Thread Peter Zijlstra
On Fri, Aug 03, 2018 at 12:40:48PM -0400, Rik van Riel wrote: > On Fri, 2018-08-03 at 17:56 +0200, Peter Zijlstra wrote: > > On Wed, Aug 01, 2018 at 06:02:55AM -0400, Rik van Riel wrote: > > > Conditionally skip lazy TLB mm refcounting. When an architecture > > > has > > > CONFIG_ARCH_NO_ACTIVE_MM_

Re: [PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-03 Thread Rik van Riel
On Fri, 2018-08-03 at 17:56 +0200, Peter Zijlstra wrote: > On Wed, Aug 01, 2018 at 06:02:55AM -0400, Rik van Riel wrote: > > Conditionally skip lazy TLB mm refcounting. When an architecture > > has > > CONFIG_ARCH_NO_ACTIVE_MM_REFCOUNTING enabled, an mm that is used in > > lazy TLB mode anywhere wi

Re: [PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-03 Thread Peter Zijlstra
On Wed, Aug 01, 2018 at 06:02:55AM -0400, Rik van Riel wrote: > Conditionally skip lazy TLB mm refcounting. When an architecture has > CONFIG_ARCH_NO_ACTIVE_MM_REFCOUNTING enabled, an mm that is used in > lazy TLB mode anywhere will get shot down from exit_mmap, and there > in no need to incur the

[PATCH 11/11] mm,sched: conditionally skip lazy TLB mm refcounting

2018-08-01 Thread Rik van Riel
Conditionally skip lazy TLB mm refcounting. When an architecture has CONFIG_ARCH_NO_ACTIVE_MM_REFCOUNTING enabled, an mm that is used in lazy TLB mode anywhere will get shot down from exit_mmap, and there in no need to incur the cache line bouncing overhead of refcounting a lazy TLB mm. Implement