From: Nico Pache <npache@redhat.com>
To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Cc: Nico Pache <npache@redhat.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Usama Arif <usama.arif@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>,
"Liam R. Howlett" <liam@infradead.org>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH v2 3/7] mm/khugepaged: introduce a count_collapse_event() helper
Date: Tue, 14 Jul 2026 20:59:32 -0600 [thread overview]
Message-ID: <20260715025941.1571316-4-npache@redhat.com> (raw)
In-Reply-To: <20260715025941.1571316-1-npache@redhat.com>
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.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Usama Arif <usama.arif@linux.dev>
Signed-off-by: Nico Pache <npache@redhat.com>
---
mm/khugepaged.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e92e2b928f17..f65bbe2051b3 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -689,6 +689,14 @@ static inline bool collapse_is_referenced(struct collapse_control *cc, pte_t pte
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)
@@ -709,9 +717,8 @@ static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
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;
@@ -753,9 +760,8 @@ static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
*/
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_folio(struct folio **foliop, struct mm_stru
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);
@@ -1662,8 +1665,7 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm,
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,
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_NONE_PTE,
MTHP_STAT_COLLAPSE_EXCEED_NONE);
goto out_unmap;
}
@@ -1672,8 +1674,7 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm,
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,
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_SWAP_PTE,
MTHP_STAT_COLLAPSE_EXCEED_SWAP);
goto out_unmap;
}
@@ -1731,8 +1732,7 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm,
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,
+ count_collapse_event(HPAGE_PMD_ORDER, THP_SCAN_EXCEED_SHARED_PTE,
MTHP_STAT_COLLAPSE_EXCEED_SHARED);
goto out_unmap;
}
--
2.54.0
next prev parent reply other threads:[~2026-07-15 3:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-15 2:59 [PATCH v2 0/7] mm/khugepaged: several cleanups Nico Pache
2026-07-15 2:59 ` [PATCH v2 1/7] mm/khugepaged: refactor per-scan state clearing into collapse_control_init_scan() Nico Pache
2026-07-15 2:59 ` [PATCH v2 2/7] mm/khugepaged: extract young page check into collapse_is_referenced() helper Nico Pache
2026-07-15 2:59 ` Nico Pache [this message]
2026-07-15 2:59 ` [PATCH v2 4/7] mm/khugepaged: fix outdated comments Nico Pache
2026-07-15 2:59 ` [PATCH v2 5/7] mm/khugepaged: Refactor the PTE state checks into a helper Nico Pache
2026-07-15 2:59 ` [PATCH v2 6/7] mm/khugepaged: unmap pte before releasing vma write lock Nico Pache
2026-07-15 2:59 ` [PATCH v2 7/7] mm: Documentation: clarify where the mTHP stats live Nico Pache
2026-07-15 4:41 ` [PATCH v2 0/7] mm/khugepaged: several cleanups Andrew Morton
2026-07-15 5:59 ` Nico Pache
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