From: Vernon Yang <vernon2gm@gmail.com>
To: akpm@linux-foundation.org, david@kernel.org
Cc: lorenzo.stoakes@oracle.com, ziy@nvidia.com, dev.jain@arm.com,
baohua@kernel.org, lance.yang@linux.dev,
richard.weiyang@gmail.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Vernon Yang <yanglincheng@kylinos.cn>
Subject: [PATCH v3 2/6] mm: khugepaged: refine scan progress number
Date: Sun, 4 Jan 2026 13:41:08 +0800 [thread overview]
Message-ID: <20260104054112.4541-3-yanglincheng@kylinos.cn> (raw)
In-Reply-To: <20260104054112.4541-1-yanglincheng@kylinos.cn>
Currently, each PMD scan always increases `progress` by HPAGE_PMD_NR,
even if only scanning a single page. By counting the actual number of
pages scanned, the `progress` is tracked accurately.
Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
---
mm/khugepaged.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 9f99f61689f8..4b124e854e2e 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1247,7 +1247,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
static int hpage_collapse_scan_pmd(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long start_addr, bool *mmap_locked,
- struct collapse_control *cc)
+ int *progress, struct collapse_control *cc)
{
pmd_t *pmd;
pte_t *pte, *_pte;
@@ -1258,23 +1258,28 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
unsigned long addr;
spinlock_t *ptl;
int node = NUMA_NO_NODE, unmapped = 0;
+ int _progress = 0;
VM_BUG_ON(start_addr & ~HPAGE_PMD_MASK);
result = find_pmd_or_thp_or_none(mm, start_addr, &pmd);
- if (result != SCAN_SUCCEED)
+ if (result != SCAN_SUCCEED) {
+ _progress = HPAGE_PMD_NR;
goto out;
+ }
memset(cc->node_load, 0, sizeof(cc->node_load));
nodes_clear(cc->alloc_nmask);
pte = pte_offset_map_lock(mm, pmd, start_addr, &ptl);
if (!pte) {
+ _progress = HPAGE_PMD_NR;
result = SCAN_NO_PTE_TABLE;
goto out;
}
for (addr = start_addr, _pte = pte; _pte < pte + HPAGE_PMD_NR;
_pte++, addr += PAGE_SIZE) {
+ _progress++;
pte_t pteval = ptep_get(_pte);
if (pte_none_or_zero(pteval)) {
++none_or_zero;
@@ -1410,6 +1415,9 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
*mmap_locked = false;
}
out:
+ if (progress)
+ *progress += _progress;
+
trace_mm_khugepaged_scan_pmd(mm, folio, referenced,
none_or_zero, result, unmapped);
return result;
@@ -2287,7 +2295,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
struct file *file, pgoff_t start,
- struct collapse_control *cc)
+ int *progress, struct collapse_control *cc)
{
struct folio *folio = NULL;
struct address_space *mapping = file->f_mapping;
@@ -2295,6 +2303,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
int present, swap;
int node = NUMA_NO_NODE;
int result = SCAN_SUCCEED;
+ int _progress = 0;
present = 0;
swap = 0;
@@ -2327,6 +2336,8 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
continue;
}
+ _progress += folio_nr_pages(folio);
+
if (folio_order(folio) == HPAGE_PMD_ORDER &&
folio->index == start) {
/* Maybe PMD-mapped */
@@ -2388,6 +2399,9 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr,
}
}
+ if (progress)
+ *progress += _progress;
+
trace_mm_khugepaged_scan_file(mm, folio, file, present, swap, result);
return result;
}
@@ -2470,7 +2484,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
mmap_read_unlock(mm);
mmap_locked = false;
*result = hpage_collapse_scan_file(mm,
- khugepaged_scan.address, file, pgoff, cc);
+ khugepaged_scan.address, file, pgoff,
+ &progress, cc);
fput(file);
if (*result == SCAN_PTE_MAPPED_HUGEPAGE) {
mmap_read_lock(mm);
@@ -2484,7 +2499,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
}
} else {
*result = hpage_collapse_scan_pmd(mm, vma,
- khugepaged_scan.address, &mmap_locked, cc);
+ khugepaged_scan.address, &mmap_locked,
+ &progress, cc);
}
if (*result == SCAN_SUCCEED)
@@ -2492,7 +2508,6 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
/* move to next address */
khugepaged_scan.address += HPAGE_PMD_SIZE;
- progress += HPAGE_PMD_NR;
if (!mmap_locked)
/*
* We released mmap_lock so break loop. Note
@@ -2810,11 +2825,11 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start,
mmap_read_unlock(mm);
mmap_locked = false;
result = hpage_collapse_scan_file(mm, addr, file, pgoff,
- cc);
+ NULL, cc);
fput(file);
} else {
result = hpage_collapse_scan_pmd(mm, vma, addr,
- &mmap_locked, cc);
+ &mmap_locked, NULL, cc);
}
if (!mmap_locked)
*lock_dropped = true;
--
2.51.0
next prev parent reply other threads:[~2026-01-04 5:41 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-04 5:41 [PATCH v3 0/6] Improve khugepaged scan logic Vernon Yang
2026-01-04 5:41 ` [PATCH v3 1/6] mm: khugepaged: add trace_mm_khugepaged_scan event Vernon Yang
2026-01-04 5:41 ` Vernon Yang [this message]
2026-01-05 16:49 ` [PATCH v3 2/6] mm: khugepaged: refine scan progress number David Hildenbrand (Red Hat)
2026-01-06 5:55 ` Vernon Yang
2026-01-04 5:41 ` [PATCH v3 3/6] mm: khugepaged: just skip when the memory has been collapsed Vernon Yang
2026-01-04 5:41 ` [PATCH v3 4/6] mm: add folio_is_lazyfree helper Vernon Yang
2026-01-04 11:42 ` Lance Yang
2026-01-05 2:09 ` Vernon Yang
2026-01-04 5:41 ` [PATCH v3 5/6] mm: khugepaged: skip lazy-free folios at scanning Vernon Yang
2026-01-04 12:10 ` Lance Yang
2026-01-05 1:48 ` Vernon Yang
2026-01-05 2:51 ` Lance Yang
2026-01-05 3:12 ` Vernon Yang
2026-01-05 3:35 ` Lance Yang
2026-01-05 12:30 ` Vernon Yang
2026-01-06 10:33 ` Barry Song
2026-01-07 8:36 ` Vernon Yang
2026-01-04 5:41 ` [PATCH v3 6/6] mm: khugepaged: set to next mm direct when mm has MMF_DISABLE_THP_COMPLETELY Vernon Yang
2026-01-04 12:20 ` Lance Yang
2026-01-05 0:31 ` Wei Yang
2026-01-05 2:09 ` Lance Yang
2026-01-05 2:06 ` Vernon Yang
2026-01-05 2:20 ` Lance Yang
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