On Thu, Sep 17, 2026 at 02:33:45PM +0200, Boris Brezillon wrote: > Right now the logic to determine whether a given VA in the drm_gpuva > being unmapped is a huge page mapping or not is scattered > in two functions: unmap_hugepage_align() and > iova_mapped_as_huge_page(). This makes it harder to reason about the > logic being implemented for very little gain (some simple checks being > done twice), so let's consolidate all the checks related to huge page > mapping testing in iova_mapped_as_huge_page() and leave > unmap_hugepage_align() as a simple user of this helper that aligns the > area to unmap based on the return of iova_mapped_as_huge_page(). > > Signed-off-by: Boris Brezillon <[email protected]>
Reviewed-by: Liviu Dudau <[email protected]> Best regards, Liviu > --- > drivers/gpu/drm/panthor/panthor_mmu.c | 57 > +++++++++++++++++------------------ > 1 file changed, 28 insertions(+), 29 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c > b/drivers/gpu/drm/panthor/panthor_mmu.c > index 6cef954e2cba..d2897099763e 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -2301,10 +2301,11 @@ iova_mapped_as_huge_page(struct drm_gpuva *mapping, > u64 va) > u64 aligned_va = ALIGN_DOWN(va, SZ_2M); > pgoff_t bo_offset; > > - /* If the 2M-aligned VA is outside the mapping being tested, we know > - * it's not a huge map. > + /* If the 2M section being tested is crossing the mapping boundary > + * we know it's not a huge map. > */ > - if (aligned_va < mapping->va.addr) > + if (aligned_va < mapping->va.addr || > + aligned_va + SZ_2M > mapping->va.addr + mapping->va.range) > return false; > > bo_offset = aligned_va - mapping->va.addr + mapping->gem.offset; > @@ -2337,10 +2338,21 @@ iova_mapped_as_huge_page(struct drm_gpuva *mapping, > u64 va) > return false; > } else { > const struct page *pg = bo->backing.pages[bo_offset >> > PAGE_SHIFT]; > + struct panthor_vma *vma = container_of(mapping, struct > panthor_vma, base); > + bool is_sparse = vma->flags & DRM_PANTHOR_VM_BIND_OP_MAP_SPARSE; > > - /* In case of shmem backing, we know we can only have a huge > mapping > - * if the bo_offset is 2M aligned, meaning we can skip the > folio size > - * check if it's not the case. > + /* If the unmapped VMA stands for a sparse mapping, always > + * assume the backing storage is a THP, since the overhead of > + * unmapping 2MiB worth of 4KiB pages and remapping some of > + * them is offset by the logic of working out whether it's > + * the opposite case right below. > + */ > + if (is_sparse) > + return true; > + > + /* In case of shmem backing, we know we can only have a huge > + * mapping if the bo_offset is 2M aligned, meaning we can skip > + * the folio size check if it's not the case. > */ > if (!IS_ALIGNED(bo_offset, SZ_2M)) > return false; > @@ -2353,36 +2365,23 @@ static void > unmap_hugepage_align(const struct drm_gpuva_op_remap *op, > u64 *unmap_start, u64 *unmap_range) > { > - struct panthor_vma *unmap_vma = container_of(op->unmap->va, struct > panthor_vma, base); > - bool is_sparse = unmap_vma->flags & DRM_PANTHOR_VM_BIND_OP_MAP_SPARSE; > - u64 aligned_unmap_start, aligned_unmap_end, unmap_end; > - > - unmap_end = *unmap_start + *unmap_range; > - aligned_unmap_start = ALIGN_DOWN(*unmap_start, SZ_2M); > - aligned_unmap_end = ALIGN(unmap_end, SZ_2M); > + u64 unmap_end = *unmap_start + *unmap_range; > > /* If we're dealing with a huge page, make sure the unmap region is > - * aligned on the start of the page. If the unmapped VMA stands for > - * a sparse mapping, always assume the backing storage is a THP, since > - * the overhead of unmapping 2MiB worth of 4KiB pages and remapping > - * some of them is offset by the logic of working out whether it's > - * the opposite case right below. This also holds true for op->next. > + * aligned on the start of the page. > */ > - if (op->prev && aligned_unmap_start < *unmap_start && > - op->prev->va.addr <= aligned_unmap_start && > - (is_sparse || iova_mapped_as_huge_page(op->unmap->va, > *unmap_start))) { > - *unmap_range += *unmap_start - aligned_unmap_start; > - *unmap_start = aligned_unmap_start; > - } > + if (op->prev && !IS_ALIGNED(*unmap_start, SZ_2M) && > + iova_mapped_as_huge_page(op->unmap->va, *unmap_start)) > + *unmap_start = ALIGN_DOWN(*unmap_start, SZ_2M); > > /* If we're dealing with a huge page, make sure the unmap region is > * aligned on the end of the page. > */ > - if (op->next && aligned_unmap_end > unmap_end && > - op->next->va.addr + op->next->va.range >= aligned_unmap_end && > - (is_sparse || iova_mapped_as_huge_page(op->unmap->va, unmap_end - > 1))) { > - *unmap_range += aligned_unmap_end - unmap_end; > - } > + if (op->next && !IS_ALIGNED(unmap_end, SZ_2M) && > + iova_mapped_as_huge_page(op->unmap->va, unmap_end - 1)) > + unmap_end = ALIGN(unmap_end, SZ_2M); > + > + *unmap_range = unmap_end - *unmap_start; > } > > static int panthor_gpuva_sm_step_remap(struct drm_gpuva_op *op, > > -- > 2.55.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯
