Re: [PATCH v9 04/14] khugepaged: generalize alloc_charge_folio()

[David Hildenbrand]

On 14.07.25 02:31, Nico Pache wrote:
From: Dev Jain <dev.j...@arm.com>
Pass order to alloc_charge_folio() and update mTHP statistics.

Reviewed-by: Baolin Wang <baolin.w...@linux.alibaba.com>
Co-developed-by: Nico Pache <npa...@redhat.com>
Signed-off-by: Nico Pache <npa...@redhat.com>
Signed-off-by: Dev Jain <dev.j...@arm.com>
---
  Documentation/admin-guide/mm/transhuge.rst |  8 ++++++++
  include/linux/huge_mm.h                    |  2 ++
  mm/huge_memory.c                           |  4 ++++
  mm/khugepaged.c                            | 17 +++++++++++------
  4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/Documentation/admin-guide/mm/transhuge.rst 
b/Documentation/admin-guide/mm/transhuge.rst
index dff8d5985f0f..2c523dce6bc7 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -583,6 +583,14 @@ anon_fault_fallback_charge
        instead falls back to using huge pages with lower orders or
        small pages even though the allocation was successful.
  
+collapse_alloc
+       is incremented every time a huge page is successfully allocated for a
+       khugepaged collapse.
+
+collapse_alloc_failed
+       is incremented every time a huge page allocation fails during a
+       khugepaged collapse.
+
  zswpout
        is incremented every time a huge page is swapped out to zswap in one
        piece without splitting.
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 7748489fde1b..4042078e8cc9 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -125,6 +125,8 @@ enum mthp_stat_item {
        MTHP_STAT_ANON_FAULT_ALLOC,
        MTHP_STAT_ANON_FAULT_FALLBACK,
        MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,
+       MTHP_STAT_COLLAPSE_ALLOC,
+       MTHP_STAT_COLLAPSE_ALLOC_FAILED,
        MTHP_STAT_ZSWPOUT,
        MTHP_STAT_SWPIN,
        MTHP_STAT_SWPIN_FALLBACK,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bd7a623d7ef8..e2ed9493df77 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -614,6 +614,8 @@ 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(collapse_alloc, MTHP_STAT_COLLAPSE_ALLOC);
+DEFINE_MTHP_STAT_ATTR(collapse_alloc_failed, MTHP_STAT_COLLAPSE_ALLOC_FAILED);
  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);
@@ -679,6 +681,8 @@ static struct attribute *any_stats_attrs[] = {
  #endif
        &split_attr.attr,
        &split_failed_attr.attr,
+       &collapse_alloc_attr.attr,
+       &collapse_alloc_failed_attr.attr,
        NULL,
  };
  
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index fa0642e66790..cc9a35185604 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1068,21 +1068,26 @@ static int __collapse_huge_page_swapin(struct mm_struct 
*mm,
  }
  
  static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm,
-                             struct collapse_control *cc)
+                             struct collapse_control *cc, u8 order)

u8, really? :)

Just use an "unsigned int" like folio_order() would or what 
__folio_alloc() consumes.



Apart from that

Acked-by: David Hildenbrand <da...@redhat.com>

--
Cheers,

David / dhildenb