Re: [PATCH v2] mm: add per-order mTHP swpin counters

["Huang, Ying" <ying.huang@intel.com>]

Barry Song <21cnbao@gmail.com> writes:

> 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.
> The new interface can be found at:
> /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats
>          swpin

This looks strange, why isn't it

/sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats/swpin

?

> For example,
> cat /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpin
> 12809
> cat /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpin
> 4763

You miss "$"?

$ cat /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpin
12809
$ cat /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpin
4763

> Signed-off-by: Barry Song <v-songbaohua@oppo.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Acked-by: David Hildenbrand <david@redhat.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>
> ---
>  -v2:
>  * collect Baolin's reviewed-by and David's acked-by, thanks!
>  * add some examples for the interface in the changelog, Per
>    Huang, Ying. thanks!
>  * add a blank line in doc which was missed in v1.
>
>  Documentation/admin-guide/mm/transhuge.rst | 4 ++++
>  include/linux/huge_mm.h                    | 1 +
>  mm/huge_memory.c                           | 3 +++
>  mm/page_io.c                               | 3 +++
>  4 files changed, 11 insertions(+)
>
> diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
> index 2a171ed5206e..5caa3fb2feb1 100644
> --- a/Documentation/admin-guide/mm/transhuge.rst
> +++ b/Documentation/admin-guide/mm/transhuge.rst
> @@ -534,6 +534,10 @@ 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
>  	swap device in one piece without splitting.
> 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 b26c6503e993..f92068864469 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);

--
Best Regards,
Huang, Ying