On Wednesday, 31 March 2021 5:49:03 AM AEDT Jason Gunthorpe wrote: > On Fri, Mar 26, 2021 at 11:08:00AM +1100, Alistair Popple wrote: > > > +static bool try_to_munlock_one(struct page *page, struct vm_area_struct *vma, > > + unsigned long address, void *arg) > > +{ > > Is this function name right? Perhaps. This is called from try_to_munlock() hence the name, but see below for some commentary on that naming. > > + struct page_vma_mapped_walk pvmw = { > > + .page = page, > > + .vma = vma, > > + .address = address, > > + }; > > + > > + /* munlock has nothing to gain from examining un-locked vmas */ > > + if (!(vma->vm_flags & VM_LOCKED)) > > + return true; > > + > > + while (page_vma_mapped_walk(&pvmw)) { > > + /* PTE-mapped THP are never mlocked */ > > + if (!PageTransCompound(page)) { > > + /* > > + * Holding pte lock, we do *not* need > > + * mmap_lock here > > + */ > > + mlock_vma_page(page); > > Because the only action this function seems to take is to call > *mlock*_vma_page() > > > + } > > + page_vma_mapped_walk_done(&pvmw); > > + > > + /* found a mlocked page, no point continuing munlock check */ > > + return false; > > + } > > + > > + return true; > > +} > > + > > /** > > * try_to_munlock - try to munlock a page > > * @page: the page to be munlocked > > @@ -1796,8 +1821,7 @@ bool try_to_unmap(struct page *page, enum ttu_flags flags) > > void try_to_munlock(struct page *page) > > { > > But this is also called try_to_munlock ?? As far as I can tell this has always been called try_to_munlock() even though it appears to do the opposite. > /** > * try_to_munlock - try to munlock a page > * @page: the page to be munlocked > * > * Called from munlock code. Checks all of the VMAs mapping the page > * to make sure nobody else has this page mlocked. The page will be > * returned with PG_mlocked cleared if no other vmas have it mlocked. > */ In other words it sets PG_mlocked if one or more vmas has it mlocked. So try_to_mlock() might be a better name, except that seems to have the potential for confusion as well because it's only called from the munlock code path and never for mlock. > So what clears PG_mlocked on this call path? See munlock_vma_page(). munlock works by clearing PG_mlocked, then calling try_to_munlock to check if any VMAs still need it locked in which case PG_mlocked gets set again. There are no other callers of try_to_munlock(). > Something needs attention here.. I think the code is correct, but perhaps the naming could be better. Would be interested hearing any thoughts on renaming try_to_munlock() to try_to_mlock() as the current name appears based on the context it is called from (munlock) rather than what it does (mlock). - Alistair > Jason > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel