Re: [PATCH 1/2] mm: add vma_has_locality()

[Yu Zhao]

On Thu, Dec 22, 2022 at 1:29 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Thu, 22 Dec 2022 12:44:35 -0700 Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> > On Thu, Dec 22, 2022 at 11:49 AM Andrew Morton
> > <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Wed, 21 Dec 2022 22:13:40 -0800 Yuanchu Xie <yuanchu@xxxxxxxxxx> wrote:
> > >
> > > > From: Yu Zhao <yuzhao@xxxxxxxxxx>
> >
> > This works; suggested-by probably works even better, since I didn't do
> > the follow-up work.
> >
> > > > Currently in vm_flags in vm_area_struct, both VM_SEQ_READ and
> > > > VM_RAND_READ indicate a lack of locality in accesses to the vma. Some
> > > > places that check for locality are missing one of them. We add
> > > > vma_has_locality to replace the existing locality checks for clarity.
> > >
> > > I'm all confused.  Surely VM_SEQ_READ implies locality and VM_RAND_READ
> > > indicates no-locality?
> >
> > Spatially, yes. But we focus more on the temporal criteria here, i.e.,
> > the reuse of an area within a relatively small duration. Both the
> > active/inactive LRU and MGLRU rely on this.
>
> Oh.  Why didn't it say that ;)
>
> How about s/locality/recency/g?

Thanks. I've done this, and posted the v2 which includes much better
commit messages.