[RFC 4/4] mm/zswap: count successful large folio zswap loads

Usama Arif
2024-10-18T10:50:45Z

Added a new MTHP_STAT_ZSWPIN entry to the sysfs transparent_hugepage
stats so that successful large folio zswap stores can be accounted under
the per-order sysfs zswpin stats:

/sys/kernel/mm/transparent_hugepage/hugepages-*kB/stats/zswpin

Signed-off-by: Usama Arif <usamaarif642@gmail.com>
---
Documentation/admin-guide/mm/transhuge.rst | 3 +++
include/linux/huge_mm.h | 1 +
mm/huge_memory.c | 3 +++
mm/page_io.c | 1 +
4 files changed, 8 insertions(+)

diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index 2a171ed5206e..68a9790908b2 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -534,6 +534,9 @@ zswpout
is incremented every time a huge page is swapped out to zswap in one
piece without splitting.

+zswpin
+ is incremented every time a huge page is swapped in from zswap.
+
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 3eca60f3d512..28a275d3107a 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_ZSWPIN,
MTHP_STAT_SWPOUT,
MTHP_STAT_SWPOUT_FALLBACK,
MTHP_STAT_SHMEM_ALLOC,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a7b05f4c2a5e..587f7dd81500 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -612,6 +612,7 @@ 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(zswpin, MTHP_STAT_ZSWPIN);
DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);
DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);
#ifdef CONFIG_SHMEM
@@ -631,6 +632,7 @@ static struct attribute *anon_stats_attrs[] = {
&anon_fault_fallback_charge_attr.attr,
#ifndef CONFIG_SHMEM
&zswpout_attr.attr,
+ &zswpin_attr.attr,
&swpout_attr.attr,
&swpout_fallback_attr.attr,
#endif
@@ -662,6 +664,7 @@ static struct attribute_group file_stats_attr_grp = {
static struct attribute *any_stats_attrs[] = {
#ifdef CONFIG_SHMEM
&zswpout_attr.attr,
+ &zswpin_attr.attr,
&swpout_attr.attr,
&swpout_fallback_attr.attr,
#endif
diff --git a/mm/page_io.c b/mm/page_io.c
index 2a15b197968a..477f9d4fc009 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -620,6 +620,7 @@ void swap_read_folio(struct folio *folio, struct swap_iocb **plug)
folio_unlock(folio);
goto finish;
} else if (zswap_load(folio)) {
+ count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPIN);
folio_unlock(folio);
goto finish;
}
--
2.43.5