On Mon, 4 Apr 2022 14:35:43 +0000 Liam Howlett <liam.howlett@xxxxxxxxxx> wrote: > From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> > > Changing mmap_region() to use the maple tree state and the advanced > maple tree interface allows for a lot less tree walking. > > This change removes the last caller of munmap_vma_range(), so drop this > unused function. > > Add vma_expand() to expand a VMA if possible by doing the necessary > hugepage check, uprobe_munmap of files, dcache flush, modifications then > undoing the detaches, etc. > Merging this with Yang Shi's "mm: mmap: register suitable readonly file vmas for khugepaged" (https://lkml.kernel.org/r/20220404200250.321455-9-shy828301@xxxxxxxxx) > ... > > @@ -1741,13 +1868,28 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > goto free_vma; > } > > - vma_link(mm, vma, prev); > + if (vma->vm_file) > + i_mmap_lock_write(vma->vm_file->f_mapping); > + > + vma_mas_store(vma, &mas); > + __vma_link_list(mm, vma, prev); > + mm->map_count++; > + if (vma->vm_file) { > + if (vma->vm_flags & VM_SHARED) > + mapping_allow_writable(vma->vm_file->f_mapping); > + > + flush_dcache_mmap_lock(vma->vm_file->f_mapping); > + vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); > + flush_dcache_mmap_unlock(vma->vm_file->f_mapping); > + i_mmap_unlock_write(vma->vm_file->f_mapping); > + } > + > /* Once vma denies write, undo our temporary denial count */ > unmap_writable: > if (file && vm_flags & VM_SHARED) > mapping_unmap_writable(file->f_mapping); I'm unsure whether this hunk should be inside or outside the call to the cheerfully undocumented khugepaged_enter_vma()? Code snippet as I presently have it: if (vma->vm_file) i_mmap_lock_write(vma->vm_file->f_mapping); vma_mas_store(vma, &mas); mm->map_count++; if (vma->vm_file) { if (vma->vm_flags & VM_SHARED) mapping_allow_writable(vma->vm_file->f_mapping); flush_dcache_mmap_lock(vma->vm_file->f_mapping); vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); flush_dcache_mmap_unlock(vma->vm_file->f_mapping); i_mmap_unlock_write(vma->vm_file->f_mapping); } /* * vma_merge() calls khugepaged_enter_vma() either, the below * call covers the non-merge case. */ khugepaged_enter_vma(vma, vma->vm_flags); /* Once vma denies write, undo our temporary denial count */ unmap_writable: if (file && vm_flags & VM_SHARED) mapping_unmap_writable(file->f_mapping); btw, "vma_merge() calls khugepaged_enter_vma() either" isn't understandable. Should that be "also"?
