search for: percpu_ref_tryget_live

Displaying 4 results from an estimated 4 matches for "percpu_ref_tryget_live".

2019 Aug 16
2
[PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk
...OK without having a get_dev_pagemap() ? > > > > Noting that the collision-retry scheme doesn't protect anything here > > as we can have a concurrent invalidation while doing the above deref. > > As long take_driver_page_table_lock() in Jerome's flow can replace > percpu_ref_tryget_live() on the pagemap reference. It seems > nouveau_dmem_convert_pfn() happens after: > > mutex_lock(&svmm->mutex); > if (!nouveau_range_done(&range)) { > > ...so I would expect that to be functionally equivalent to validating...
2019 Aug 15
4
[PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk
On Thu, Aug 15, 2019 at 04:33:06PM -0400, Jerome Glisse wrote: > So nor HMM nor driver should dereference the struct page (i do not > think any iommu driver would either), Er, they do technically deref the struct page: nouveau_dmem_convert_pfn(struct nouveau_drm *drm, struct hmm_range *range) struct page *page; page = hmm_pfn_to_page(range, range->pfns[i]); if
2019 Aug 15
0
[PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk
...;pgmap' > > Is this OK without having a get_dev_pagemap() ? > > Noting that the collision-retry scheme doesn't protect anything here > as we can have a concurrent invalidation while doing the above deref. As long take_driver_page_table_lock() in Jerome's flow can replace percpu_ref_tryget_live() on the pagemap reference. It seems nouveau_dmem_convert_pfn() happens after: mutex_lock(&svmm->mutex); if (!nouveau_range_done(&range)) { ...so I would expect that to be functionally equivalent to validating the reference count.
2019 Aug 16
0
[PATCH 04/15] mm: remove the pgmap field from struct hmm_vma_walk
...agemap() ? > > > > > > Noting that the collision-retry scheme doesn't protect anything here > > > as we can have a concurrent invalidation while doing the above deref. > > > > As long take_driver_page_table_lock() in Jerome's flow can replace > > percpu_ref_tryget_live() on the pagemap reference. It seems > > nouveau_dmem_convert_pfn() happens after: > > > > mutex_lock(&svmm->mutex); > > if (!nouveau_range_done(&range)) { > > > > ...so I would expect that to be function...