Re: [PATCH] mm: add per-order mTHP swpin counters

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 2024/10/26 16:24, Barry Song wrote:
> From: Barry Song <v-songbaohua@oppo.com>
> 
> This helps profile the sizes of folios being swapped in. Currently,
> only mTHP swap-out is being counted.
> 
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: Chris Li <chrisl@kernel.org>
> Cc: Yosry Ahmed <yosryahmed@google.com>
> Cc: "Huang, Ying" <ying.huang@intel.com>
> Cc: Kairui Song <kasong@tencent.com>
> Cc: Ryan Roberts <ryan.roberts@arm.com>
> Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
> Cc: Usama Arif <usamaarif642@gmail.com>
> Signed-off-by: Barry Song <v-songbaohua@oppo.com>

Looks reasonable to me.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>

> ---
>   Documentation/admin-guide/mm/transhuge.rst | 3 +++
>   include/linux/huge_mm.h                    | 1 +
>   mm/huge_memory.c                           | 3 +++
>   mm/page_io.c                               | 3 +++
>   4 files changed, 10 insertions(+)
> 
> diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
> index 2a171ed5206e..203ba7aaf5fc 100644
> --- a/Documentation/admin-guide/mm/transhuge.rst
> +++ b/Documentation/admin-guide/mm/transhuge.rst
> @@ -533,6 +533,9 @@ anon_fault_fallback_charge
>   zswpout
>   	is incremented every time a huge page is swapped out to zswap in one
>   	piece without splitting.
> +swpin
> +	is incremented every time a huge page is swapped in from a non-zswap
> +	swap device in one piece.
>   
>   swpout
>   	is incremented every time a huge page is swapped out to a non-zswap
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index c59e5aa9b081..b94c2e8ee918 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -120,6 +120,7 @@ enum mthp_stat_item {
>   	MTHP_STAT_ANON_FAULT_FALLBACK,
>   	MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,
>   	MTHP_STAT_ZSWPOUT,
> +	MTHP_STAT_SWPIN,
>   	MTHP_STAT_SWPOUT,
>   	MTHP_STAT_SWPOUT_FALLBACK,
>   	MTHP_STAT_SHMEM_ALLOC,
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 830d6aa5bf97..846c1a43f61c 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -616,6 +616,7 @@ DEFINE_MTHP_STAT_ATTR(anon_fault_alloc, MTHP_STAT_ANON_FAULT_ALLOC);
>   DEFINE_MTHP_STAT_ATTR(anon_fault_fallback, MTHP_STAT_ANON_FAULT_FALLBACK);
>   DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
>   DEFINE_MTHP_STAT_ATTR(zswpout, MTHP_STAT_ZSWPOUT);
> +DEFINE_MTHP_STAT_ATTR(swpin, MTHP_STAT_SWPIN);
>   DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);
>   DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);
>   #ifdef CONFIG_SHMEM
> @@ -635,6 +636,7 @@ static struct attribute *anon_stats_attrs[] = {
>   	&anon_fault_fallback_charge_attr.attr,
>   #ifndef CONFIG_SHMEM
>   	&zswpout_attr.attr,
> +	&swpin_attr.attr,
>   	&swpout_attr.attr,
>   	&swpout_fallback_attr.attr,
>   #endif
> @@ -666,6 +668,7 @@ static struct attribute_group file_stats_attr_grp = {
>   static struct attribute *any_stats_attrs[] = {
>   #ifdef CONFIG_SHMEM
>   	&zswpout_attr.attr,
> +	&swpin_attr.attr,
>   	&swpout_attr.attr,
>   	&swpout_fallback_attr.attr,
>   #endif
> diff --git a/mm/page_io.c b/mm/page_io.c
> index c69fab5060a1..5d9b6e6cf96c 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -487,6 +487,7 @@ static void sio_read_complete(struct kiocb *iocb, long ret)
>   		for (p = 0; p < sio->pages; p++) {
>   			struct folio *folio = page_folio(sio->bvec[p].bv_page);
>   
> +			count_mthp_stat(folio_order(folio), MTHP_STAT_SWPIN);
>   			count_memcg_folio_events(folio, PSWPIN, folio_nr_pages(folio));
>   			folio_mark_uptodate(folio);
>   			folio_unlock(folio);
> @@ -573,6 +574,7 @@ static void swap_read_folio_bdev_sync(struct folio *folio,
>   	 * attempt to access it in the page fault retry time check.
>   	 */
>   	get_task_struct(current);
> +	count_mthp_stat(folio_order(folio), MTHP_STAT_SWPIN);
>   	count_memcg_folio_events(folio, PSWPIN, folio_nr_pages(folio));
>   	count_vm_events(PSWPIN, folio_nr_pages(folio));
>   	submit_bio_wait(&bio);
> @@ -589,6 +591,7 @@ static void swap_read_folio_bdev_async(struct folio *folio,
>   	bio->bi_iter.bi_sector = swap_folio_sector(folio);
>   	bio->bi_end_io = end_swap_bio_read;
>   	bio_add_folio_nofail(bio, folio, folio_size(folio), 0);
> +	count_mthp_stat(folio_order(folio), MTHP_STAT_SWPIN);
>   	count_memcg_folio_events(folio, PSWPIN, folio_nr_pages(folio));
>   	count_vm_events(PSWPIN, folio_nr_pages(folio));
>   	submit_bio(bio);