Re: [PATCH RFC/RFT 1/4] riscv: Stop emitting preventive sfence.vma for new vmalloc mappings

2023-12-08 Thread Alexandre Ghiti
Hi Christophe, On Thu, Dec 7, 2023 at 4:52 PM Christophe Leroy wrote: > > > > Le 07/12/2023 à 16:03, Alexandre Ghiti a écrit : > > In 6.5, we removed the vmalloc fault path because that can't work (see > > [1] [2]). Then in order to make sure that new page table entries were > > seen by the page

Re: [PATCH RFC/RFT 1/4] riscv: Stop emitting preventive sfence.vma for new vmalloc mappings

2023-12-07 Thread Christophe Leroy
Le 07/12/2023 à 16:03, Alexandre Ghiti a écrit : > In 6.5, we removed the vmalloc fault path because that can't work (see > [1] [2]). Then in order to make sure that new page table entries were > seen by the page table walker, we had to preventively emit a sfence.vma > on all harts [3] but this

[PATCH RFC/RFT 1/4] riscv: Stop emitting preventive sfence.vma for new vmalloc mappings

2023-12-07 Thread Alexandre Ghiti
In 6.5, we removed the vmalloc fault path because that can't work (see [1] [2]). Then in order to make sure that new page table entries were seen by the page table walker, we had to preventively emit a sfence.vma on all harts [3] but this solution is very costly since it relies on IPI. And even