On Wed, Mar 31, 2021 at 09:09:30AM +1100, Alistair Popple wrote:
> > > @@ -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.
Maybe we should change it then?
> > /**
> > * 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.
That explanation makes more sense.. This function looks like it is
'set PG_mlocked of the page if any vm->flags has VM_LOCKED'
Maybe call it check_vm_locked or something then and reword the above
comment?
(and why is it OK to read vm->flags for this without any locking?)
> > 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).
The point of this patch is to make it clearer, after all, so I'd
change something and maybe slightly clarify the comment.
Jason
