Re: [PATCH] powerpc/mm/cxl: Add barrier when setting mm cpumask

2017-08-28 Thread Benjamin Herrenschmidt
On Mon, 2017-08-28 at 13:23 +0530, Aneesh Kumar K.V wrote: > Benjamin Herrenschmidt writes: > > > On Mon, 2017-08-28 at 11:55 +0530, Aneesh Kumar K.V wrote: > > > We need to add memory barrier so that the page table walk doesn't happen > > > before the cpumask is set and made visible to the other

Re: [PATCH] powerpc/mm/cxl: Add barrier when setting mm cpumask

2017-08-28 Thread Aneesh Kumar K.V
Benjamin Herrenschmidt writes: > On Mon, 2017-08-28 at 11:55 +0530, Aneesh Kumar K.V wrote: >> We need to add memory barrier so that the page table walk doesn't happen >> before the cpumask is set and made visible to the other cpus. We need >> to use a sync here instead of lwsync because lwsync i

Re: [PATCH] powerpc/mm/cxl: Add barrier when setting mm cpumask

2017-08-27 Thread Benjamin Herrenschmidt
On Mon, 2017-08-28 at 11:55 +0530, Aneesh Kumar K.V wrote: > We need to add memory barrier so that the page table walk doesn't happen > before the cpumask is set and made visible to the other cpus. We need > to use a sync here instead of lwsync because lwsync is not sufficient for > store/load orde

Re: [PATCH] powerpc/mm/cxl: Add barrier when setting mm cpumask

2017-08-27 Thread Andrew Donnellan
On 28/08/17 16:25, Aneesh Kumar K.V wrote: We need to add memory barrier so that the page table walk doesn't happen before the cpumask is set and made visible to the other cpus. We need to use a sync here instead of lwsync because lwsync is not sufficient for store/load ordering. We also need to

[PATCH] powerpc/mm/cxl: Add barrier when setting mm cpumask

2017-08-27 Thread Aneesh Kumar K.V
We need to add memory barrier so that the page table walk doesn't happen before the cpumask is set and made visible to the other cpus. We need to use a sync here instead of lwsync because lwsync is not sufficient for store/load ordering. We also need to add an if (mm) check so that we do the right