Commit 67c8b11b authored by Wenchao Hao's avatar Wenchao Hao Committed by Andrew Morton
Browse files

mm: add per-order mTHP swap-in fallback/fallback_charge counters 

Currently, large folio swap-in is supported, but we lack a method to
analyze their success ratio.  Similar to anon_fault_fallback, we introduce
per-order mTHP swpin_fallback and swpin_fallback_charge counters for
calculating their success ratio.  The new counters are located at:

/sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats/
	swpin_fallback
	swpin_fallback_charge

Link: https://lkml.kernel.org/r/20241202124730.2407037-1-haowenchao22@gmail.com


Signed-off-by: default avatarWenchao Hao <haowenchao22@gmail.com>
Reviewed-by: default avatarBarry Song <baohua@kernel.org>
Reviewed-by: default avatarLance Yang <ioworker0@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 4817f70c

Documentation/admin-guide/mm/transhuge.rst

+10 −0
Original line number Diff line number Diff line
@@ -591,6 +591,16 @@ swpin 
	is incremented every time a huge page is swapped in from a non-zswap

	swap device in one piece.



swpin_fallback

	is incremented if swapin fails to allocate or charge a huge page

	and instead falls back to using huge pages with lower orders or

	small pages.



swpin_fallback_charge

	is incremented if swapin fails to charge a huge page and 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 to a non-zswap

	swap device in one piece without splitting.

include/linux/huge_mm.h

+2 −0
Original line number Diff line number Diff line
@@ -121,6 +121,8 @@ enum mthp_stat_item { 
	MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,

	MTHP_STAT_ZSWPOUT,

	MTHP_STAT_SWPIN,

	MTHP_STAT_SWPIN_FALLBACK,

	MTHP_STAT_SWPIN_FALLBACK_CHARGE,

	MTHP_STAT_SWPOUT,

	MTHP_STAT_SWPOUT_FALLBACK,

	MTHP_STAT_SHMEM_ALLOC,

mm/huge_memory.c

+6 −0
Original line number Diff line number Diff line
@@ -617,6 +617,8 @@ 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(swpin_fallback, MTHP_STAT_SWPIN_FALLBACK);

DEFINE_MTHP_STAT_ATTR(swpin_fallback_charge, MTHP_STAT_SWPIN_FALLBACK_CHARGE);

DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);

DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);

#ifdef CONFIG_SHMEM
@@ -637,6 +639,8 @@ static struct attribute *anon_stats_attrs[] = { 
#ifndef CONFIG_SHMEM

	&zswpout_attr.attr,

	&swpin_attr.attr,

	&swpin_fallback_attr.attr,

	&swpin_fallback_charge_attr.attr,

	&swpout_attr.attr,

	&swpout_fallback_attr.attr,

#endif
@@ -669,6 +673,8 @@ static struct attribute *any_stats_attrs[] = { 
#ifdef CONFIG_SHMEM

	&zswpout_attr.attr,

	&swpin_attr.attr,

	&swpin_fallback_attr.attr,

	&swpin_fallback_charge_attr.attr,

	&swpout_attr.attr,

	&swpout_fallback_attr.attr,

#endif

mm/memory.c

+2 −0
Original line number Diff line number Diff line
@@ -4258,8 +4258,10 @@ static struct folio *alloc_swap_folio(struct vm_fault *vmf) 
			if (!mem_cgroup_swapin_charge_folio(folio, vma->vm_mm,

							    gfp, entry))

				return folio;

			count_mthp_stat(order, MTHP_STAT_SWPIN_FALLBACK_CHARGE);

			folio_put(folio);

		}

		count_mthp_stat(order, MTHP_STAT_SWPIN_FALLBACK);

		order = next_order(&orders, order);

	}