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.
--
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:
