On Tue, Jul 11, 2023 at 1:21 PM Matthew Wilcox (Oracle)
<willy@xxxxxxxxxxxxx> wrote:
>
> Perform the check at the start of do_read_fault(), do_cow_fault()
> and do_shared_fault() instead. Should be no performance change from
> the last commit.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
> ---
> mm/memory.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 88cf9860f17e..709bffee8aa2 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4547,6 +4547,11 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf)
> vm_fault_t ret = 0;
> struct folio *folio;
>
> + if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
> + vma_end_read(vmf->vma);
> + return VM_FAULT_RETRY;
> + }
> +
> /*
> * Let's call ->map_pages() first and use ->fault() as fallback
> * if page by the offset is not ready to be mapped (cold cache or
> @@ -4575,6 +4580,11 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
> struct vm_area_struct *vma = vmf->vma;
> vm_fault_t ret;
>
> + if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
> + vma_end_read(vma);
> + return VM_FAULT_RETRY;
> + }
> +
> if (unlikely(anon_vma_prepare(vma)))
> return VM_FAULT_OOM;
>
> @@ -4615,6 +4625,11 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
> vm_fault_t ret, tmp;
> struct folio *folio;
>
> + if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
> + vma_end_read(vma);
> + return VM_FAULT_RETRY;
> + }
> +
> ret = __do_fault(vmf);
> if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
> return ret;
> @@ -4661,11 +4676,6 @@ static vm_fault_t do_fault(struct vm_fault *vmf)
> struct mm_struct *vm_mm = vma->vm_mm;
> vm_fault_t ret;
>
> - if (vmf->flags & FAULT_FLAG_VMA_LOCK){
> - vma_end_read(vma);
> - return VM_FAULT_RETRY;
> - }
> -
> /*
> * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND
> */
> --
> 2.39.2
>
