Commit 0c560dd8 authored by Kanchana P Sridhar's avatar Kanchana P Sridhar Committed by Andrew Morton
Browse files

mm: swap: count successful large folio zswap stores in hugepage zswpout stats 

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

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

Other non-zswap swap device swap-out events will be counted under
the existing sysfs "swpout" stats:

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

Also, added documentation for the newly added sysfs per-order hugepage
"zswpout" stats. The documentation clarifies that only non-zswap swapouts
will be accounted in the existing "swpout" stats.

Link: https://lkml.kernel.org/r/20241001053222.6944-8-kanchana.p.sridhar@intel.com


Signed-off-by: default avatarKanchana P Sridhar <kanchana.p.sridhar@intel.com>
Reviewed-by: default avatarNhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Wajdi Feghali <wajdi.k.feghali@intel.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: "Zou, Nanhai" <nanhai.zou@intel.com>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b7c0ccdf

Documentation/admin-guide/mm/transhuge.rst

+6 −2
Original line number Diff line number Diff line
@@ -530,10 +530,14 @@ anon_fault_fallback_charge 
	instead falls back to using huge pages with lower orders or

	small pages even though the allocation was successful.



swpout

	is incremented every time a huge page is swapped out in one

zswpout

	is incremented every time a huge page is swapped out to zswap in one

	piece without splitting.



swpout

	is incremented every time a huge page is swapped out to a non-zswap

	swap device in one piece without splitting.



swpout_fallback

	is incremented if a huge page has to be split before swapout.

	Usually because failed to allocate some continuous swap space

include/linux/huge_mm.h

+1 −0
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ enum mthp_stat_item { 
	MTHP_STAT_ANON_FAULT_ALLOC,

	MTHP_STAT_ANON_FAULT_FALLBACK,

	MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,

	MTHP_STAT_ZSWPOUT,

	MTHP_STAT_SWPOUT,

	MTHP_STAT_SWPOUT_FALLBACK,

	MTHP_STAT_SHMEM_ALLOC,

mm/huge_memory.c

+3 −0
Original line number Diff line number Diff line
@@ -615,6 +615,7 @@ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 
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(swpout, MTHP_STAT_SWPOUT);

DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);

#ifdef CONFIG_SHMEM
@@ -633,6 +634,7 @@ static struct attribute *anon_stats_attrs[] = { 
	&anon_fault_fallback_attr.attr,

	&anon_fault_fallback_charge_attr.attr,

#ifndef CONFIG_SHMEM

	&zswpout_attr.attr,

	&swpout_attr.attr,

	&swpout_fallback_attr.attr,

#endif
@@ -663,6 +665,7 @@ static struct attribute_group file_stats_attr_grp = { 


static struct attribute *any_stats_attrs[] = {

#ifdef CONFIG_SHMEM

	&zswpout_attr.attr,

	&swpout_attr.attr,

	&swpout_fallback_attr.attr,

#endif

mm/page_io.c

+1 −0
Original line number Diff line number Diff line
@@ -277,6 +277,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) 
		swap_zeromap_folio_clear(folio);

	}

	if (zswap_store(folio)) {

		count_mthp_stat(folio_order(folio), MTHP_STAT_ZSWPOUT);

		folio_unlock(folio);

		return 0;

	}