From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,nico.pache@linux.dev,akpm@linux-foundation.org
Subject: + mm-khugepaged-introduce-a-count_collapse_event-helper.patch added to mm-unstable branch
Date: Tue, 11 Aug 2026 11:24:25 -0700 [thread overview]
Message-ID: <20260811182425.B5A761F000E9@smtp.kernel.org> (raw)
The patch titled
Subject: mm/khugepaged: introduce a count_collapse_event() helper
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-introduce-a-count_collapse_event-helper.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-introduce-a-count_collapse_event-helper.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Nico Pache (Red Hat)" <nico.pache@linux.dev>
Subject: mm/khugepaged: introduce a count_collapse_event() helper
Date: Tue, 11 Aug 2026 06:48:35 -0600
Provide a simple helper function to help reduce a often used, and
duplicate pattern across the khugepaged code.
When collapsing to a PMD we need to record a vm_event and the mTHP_stat
event. When doing mTHP collapse we only update the mTHP stat.
Link: https://lore.kernel.org/20260811-khugepaged_pte_refactor-v4-3-ddac39d61c4a@linux.dev
Signed-off-by: Nico Pache (Red Hat) <nico.pache@linux.dev>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/khugepaged.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)
--- a/mm/khugepaged.c~mm-khugepaged-introduce-a-count_collapse_event-helper
+++ a/mm/khugepaged.c
@@ -688,6 +688,14 @@ static inline bool folio_pte_referenced(
return pte_young(pteval) || mmu_notifier_test_young(vma->vm_mm, addr);
}
+static void count_collapse_event(unsigned int order, enum vm_event_item vm_event,
+ enum mthp_stat_item mthp_event)
+{
+ if (is_pmd_order(order))
+ count_vm_event(vm_event);
+ count_mthp_stat(order, mthp_event);
+}
+
static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
unsigned long start_addr, pte_t *pte, struct collapse_control *cc,
unsigned int order, struct list_head *compound_pagelist)
@@ -708,9 +716,8 @@ static enum scan_result __collapse_huge_
if (pte_none_or_zero(pteval)) {
if (++none_or_zero > max_ptes_none) {
result = SCAN_EXCEED_NONE_PTE;
- if (is_pmd_order(order))
- count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
- count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_NONE);
+ count_collapse_event(order, THP_SCAN_EXCEED_NONE_PTE,
+ MTHP_STAT_COLLAPSE_EXCEED_NONE);
goto out;
}
continue;
@@ -752,9 +759,8 @@ static enum scan_result __collapse_huge_
*/
if (++shared > max_ptes_shared) {
result = SCAN_EXCEED_SHARED_PTE;
- if (is_pmd_order(order))
- count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
- count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_SHARED);
+ count_collapse_event(order, THP_SCAN_EXCEED_SHARED_PTE,
+ MTHP_STAT_COLLAPSE_EXCEED_SHARED);
goto out;
}
}
@@ -1264,15 +1270,12 @@ static enum scan_result alloc_charge_fol
folio = __folio_alloc(gfp, order, node, &cc->alloc_nmask);
if (!folio) {
*foliop = NULL;
- if (is_pmd_order(order))
- count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
- count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC_FAILED);
+ count_collapse_event(order, THP_COLLAPSE_ALLOC_FAILED,
+ MTHP_STAT_COLLAPSE_ALLOC_FAILED);
return SCAN_ALLOC_HUGE_PAGE_FAIL;
}
- if (is_pmd_order(order))
- count_vm_event(THP_COLLAPSE_ALLOC);
- count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC);
+ count_collapse_event(order, THP_COLLAPSE_ALLOC, MTHP_STAT_COLLAPSE_ALLOC);
if (unlikely(mem_cgroup_charge(folio, mm, gfp))) {
folio_put(folio);
@@ -1662,9 +1665,8 @@ static enum scan_result collapse_scan_pm
if (pte_none_or_zero(pteval)) {
if (++none_or_zero > max_ptes_none) {
result = SCAN_EXCEED_NONE_PTE;
- count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
- count_mthp_stat(HPAGE_PMD_ORDER,
- MTHP_STAT_COLLAPSE_EXCEED_NONE);
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_NONE_PTE,
+ MTHP_STAT_COLLAPSE_EXCEED_NONE);
goto out_unmap;
}
continue;
@@ -1672,9 +1674,8 @@ static enum scan_result collapse_scan_pm
if (!pte_present(pteval)) {
if (++unmapped > max_ptes_swap) {
result = SCAN_EXCEED_SWAP_PTE;
- count_vm_event(THP_SCAN_EXCEED_SWAP_PTE);
- count_mthp_stat(HPAGE_PMD_ORDER,
- MTHP_STAT_COLLAPSE_EXCEED_SWAP);
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_SWAP_PTE,
+ MTHP_STAT_COLLAPSE_EXCEED_SWAP);
goto out_unmap;
}
/*
@@ -1731,9 +1732,8 @@ static enum scan_result collapse_scan_pm
if (folio_maybe_mapped_shared(folio)) {
if (++shared > max_ptes_shared) {
result = SCAN_EXCEED_SHARED_PTE;
- count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
- count_mthp_stat(HPAGE_PMD_ORDER,
- MTHP_STAT_COLLAPSE_EXCEED_SHARED);
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_SHARED_PTE,
+ MTHP_STAT_COLLAPSE_EXCEED_SHARED);
goto out_unmap;
}
}
_
Patches currently in -mm which might be from nico.pache@linux.dev are
mm-khugepaged-refactor-per-scan-state-clearing-into-collapse_control_init_scan.patch
mm-khugepaged-extract-reference-check-into-folio_pte_referenced-helper.patch
mm-khugepaged-introduce-a-count_collapse_event-helper.patch
mm-khugepaged-fix-outdated-comments.patch
mm-khugepaged-refactor-the-pte-state-checks-into-a-helper.patch
mm-khugepaged-unmap-pte-before-releasing-vma-write-lock.patch
mm-documentation-clarify-where-the-mthp-stats-live.patch
reply other threads:[~2026-08-11 18:24 UTC|newest]
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