[PATCH v11 04/15] khugepaged: generalize alloc_charge_folio()
From: Nico Pache <npache@redhat.com>
Date: 2025-09-12 03:30:10
Also in:
linux-doc, linux-mm, lkml
Subsystem:
documentation, memory management, memory management - misc, memory management - thp (transparent huge page), the rest · Maintainers:
Jonathan Corbet, Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
From: Dev Jain <dev.jain@arm.com> Pass order to alloc_charge_folio() and update mTHP statistics. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lorenzo Stoakes <redacted> Acked-by: David Hildenbrand <redacted> Co-developed-by: Nico Pache <npache@redhat.com> Signed-off-by: Nico Pache <npache@redhat.com> Signed-off-by: Dev Jain <dev.jain@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 1654211cc6cf..13269a0074d4 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst@@ -634,6 +634,14 @@ 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 a166be872628..d442f45bd458 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h@@ -128,6 +128,8 @@ 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 d6fc669e11c1..76509e3d845b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -620,6 +620,8 @@ 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);
@@ -685,6 +687,8 @@ 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 6dbe2d0683ac..2dea49522755 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c@@ -1071,21 +1071,26 @@ 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, unsigned int order) { gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : GFP_TRANSHUGE); int node = collapse_find_target_node(cc); struct folio *folio; - folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, &cc->alloc_nmask); + folio = __folio_alloc(gfp, order, node, &cc->alloc_nmask); if (!folio) { *foliop = NULL; - count_vm_event(THP_COLLAPSE_ALLOC_FAILED); + if (order == HPAGE_PMD_ORDER) + count_vm_event(THP_COLLAPSE_ALLOC_FAILED); + count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC_FAILED); return SCAN_ALLOC_HUGE_PAGE_FAIL; } - count_vm_event(THP_COLLAPSE_ALLOC); + if (order == HPAGE_PMD_ORDER) + count_vm_event(THP_COLLAPSE_ALLOC); + count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC); + if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { folio_put(folio); *foliop = NULL;
@@ -1122,7 +1127,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, */ mmap_read_unlock(mm); - result = alloc_charge_folio(&folio, mm, cc); + result = alloc_charge_folio(&folio, mm, cc, HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) goto out_nolock;
@@ -1850,7 +1855,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); VM_BUG_ON(start & (HPAGE_PMD_NR - 1)); - result = alloc_charge_folio(&new_folio, mm, cc); + result = alloc_charge_folio(&new_folio, mm, cc, HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) goto out;
--
2.51.0