On Wed, Apr 17, 2024 at 1:40 PM Huang, Ying <ying.huang@xxxxxxxxx> wrote:
>
> Barry Song <21cnbao@xxxxxxxxx> writes:
>
> > On Wed, Apr 17, 2024 at 8:47 AM Huang, Ying <ying.huang@xxxxxxxxx> wrote:
> >>
> >> Barry Song <21cnbao@xxxxxxxxx> writes:
> >>
> >> > From: Barry Song <v-songbaohua@xxxxxxxx>
> >> >
> >> > Currently, we are handling the scenario where we've hit a
> >> > large folio in the swapcache, and the reclaiming process
> >> > for this large folio is still ongoing.
> >> >
> >> > Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
> >> > ---
> >> > include/linux/huge_mm.h | 1 +
> >> > mm/huge_memory.c | 2 ++
> >> > mm/memory.c | 1 +
> >> > 3 files changed, 4 insertions(+)
> >> >
> >> > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> >> > index c8256af83e33..b67294d5814f 100644
> >> > --- a/include/linux/huge_mm.h
> >> > +++ b/include/linux/huge_mm.h
> >> > @@ -269,6 +269,7 @@ enum mthp_stat_item {
> >> > MTHP_STAT_ANON_ALLOC_FALLBACK,
> >> > MTHP_STAT_ANON_SWPOUT,
> >> > MTHP_STAT_ANON_SWPOUT_FALLBACK,
> >> > + MTHP_STAT_ANON_SWPIN_REFAULT,
> >>
> >> This is different from the refault concept used in other place in mm
> >> subystem. Please check the following code
> >>
> >> if (shadow)
> >> workingset_refault(folio, shadow);
> >>
> >> in __read_swap_cache_async().
> >
> > right. it is slightly different as refault can also cover the case folios
> > have been entirely released and a new page fault happens soon
> > after it.
> > Do you have a better name for this?
> > MTHP_STAT_ANON_SWPIN_UNDER_RECLAIM
> > or
> > MTHP_STAT_ANON_SWPIN_RECLAIMING ?
>
> TBH, I don't think we need this counter. It's important for you during
> implementation. But I don't think it's important for end users.
Okay. If we can't find a shared interest between the
implementer and user, I'm perfectly fine with keeping it
local only for debugging purposes.
>
> --
> Best Regards,
> Huang, Ying
>
> >>
> >> > __MTHP_STAT_COUNT
> >> > };
> >>
> >> --
> >> Best Regards,
> >> Huang, Ying
> >>
> >> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> >> > index d8d2ed80b0bf..fb95345b0bde 100644
> >> > --- a/mm/huge_memory.c
> >> > +++ b/mm/huge_memory.c
> >> > @@ -556,12 +556,14 @@ DEFINE_MTHP_STAT_ATTR(anon_alloc, MTHP_STAT_ANON_ALLOC);
> >> > DEFINE_MTHP_STAT_ATTR(anon_alloc_fallback, MTHP_STAT_ANON_ALLOC_FALLBACK);
> >> > DEFINE_MTHP_STAT_ATTR(anon_swpout, MTHP_STAT_ANON_SWPOUT);
> >> > DEFINE_MTHP_STAT_ATTR(anon_swpout_fallback, MTHP_STAT_ANON_SWPOUT_FALLBACK);
> >> > +DEFINE_MTHP_STAT_ATTR(anon_swpin_refault, MTHP_STAT_ANON_SWPIN_REFAULT);
> >> >
> >> > static struct attribute *stats_attrs[] = {
> >> > &anon_alloc_attr.attr,
> >> > &anon_alloc_fallback_attr.attr,
> >> > &anon_swpout_attr.attr,
> >> > &anon_swpout_fallback_attr.attr,
> >> > + &anon_swpin_refault_attr.attr,
> >> > NULL,
> >> > };
> >> >
> >> > diff --git a/mm/memory.c b/mm/memory.c
> >> > index 9818dc1893c8..acc023795a4d 100644
> >> > --- a/mm/memory.c
> >> > +++ b/mm/memory.c
> >> > @@ -4167,6 +4167,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> >> > nr_pages = nr;
> >> > entry = folio->swap;
> >> > page = &folio->page;
> >> > + count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT);
> >> > }
> >> >
> >> > check_pte:
