From: SeongJae Park <sj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj@kernel.org>,
damon@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Hugh Dickins <hughd@google.com>
Subject: [PATCH 3/9] mm/damon/vaddr: cleanup using pmd_trans_huge_lock()
Date: Wed, 12 Nov 2025 07:41:06 -0800 [thread overview]
Message-ID: <20251112154114.66053-4-sj@kernel.org> (raw)
In-Reply-To: <20251112154114.66053-1-sj@kernel.org>
Three pmd walk functions in vaddr.c are using pmd_trans_huge() and
pmd_lock() to handle THPs. Simplify the code by replacing the two
function calls with a single pmd_trans_huge_lock() call.
Note that this cleanup is not only reducing the lines of code, but also
simplifies code execution flows for migration entries case, as kindly
explained [1] by Hugh, who suggested this cleanup.
[1] https://lore.kernel.org/296c2b3f-6748-158f-b85d-2952165c0588@google.com
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/vaddr.c | 48 ++++++++++++------------------------------------
1 file changed, 12 insertions(+), 36 deletions(-)
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 7e834467b2d8..0ad1ce120aa1 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -307,24 +307,14 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_t *pte;
- pmd_t pmde;
spinlock_t *ptl;
- if (pmd_trans_huge(pmdp_get(pmd))) {
- ptl = pmd_lock(walk->mm, pmd);
- pmde = pmdp_get(pmd);
-
- if (!pmd_present(pmde)) {
- spin_unlock(ptl);
- return 0;
- }
-
- if (pmd_trans_huge(pmde)) {
+ ptl = pmd_trans_huge_lock(pmd, walk->vma);
+ if (ptl) {
+ if (pmd_present(pmdp_get(pmd)))
damon_pmdp_mkold(pmd, walk->vma, addr);
- spin_unlock(ptl);
- return 0;
- }
spin_unlock(ptl);
+ return 0;
}
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
@@ -446,21 +436,12 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
struct damon_young_walk_private *priv = walk->private;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- if (pmd_trans_huge(pmdp_get(pmd))) {
- pmd_t pmde;
-
- ptl = pmd_lock(walk->mm, pmd);
- pmde = pmdp_get(pmd);
+ ptl = pmd_trans_huge_lock(pmd, walk->vma);
+ if (ptl) {
+ pmd_t pmde = pmdp_get(pmd);
- if (!pmd_present(pmde)) {
- spin_unlock(ptl);
- return 0;
- }
-
- if (!pmd_trans_huge(pmde)) {
- spin_unlock(ptl);
- goto regular_page;
- }
+ if (!pmd_present(pmde))
+ goto huge_out;
folio = damon_get_folio(pmd_pfn(pmde));
if (!folio)
goto huge_out;
@@ -474,8 +455,6 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
spin_unlock(ptl);
return 0;
}
-
-regular_page:
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
@@ -910,13 +889,10 @@ static int damos_va_stat_pmd_entry(pmd_t *pmd, unsigned long addr,
int nr;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- if (pmd_trans_huge(*pmd)) {
- pmd_t pmde;
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
+ pmd_t pmde = pmdp_get(pmd);
- ptl = pmd_trans_huge_lock(pmd, vma);
- if (!ptl)
- return 0;
- pmde = pmdp_get(pmd);
if (!pmd_present(pmde))
goto huge_unlock;
--
2.47.3
next prev parent reply other threads:[~2025-11-12 15:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-12 15:41 [PATCH 0/9] mm/damon: misc cleanups SeongJae Park
2025-11-12 15:41 ` [PATCH 1/9] mm/damon: rename damos core filter helpers to have word core SeongJae Park
2025-11-12 15:41 ` [PATCH 2/9] mm/damon: rename damos->filters to damos->core_filters SeongJae Park
2025-11-12 15:41 ` SeongJae Park [this message]
2025-11-17 15:44 ` [PATCH 3/9] mm/damon/vaddr: cleanup using pmd_trans_huge_lock() SeongJae Park
2025-11-12 15:41 ` [PATCH 4/9] mm/damon/vaddr: use vm_normal_folio{,_pmd}() instead of damon_get_folio() SeongJae Park
2025-11-12 15:41 ` [PATCH 5/9] mm/damon/vaddr: consistently use only pmd_entry for damos_migrate SeongJae Park
2025-11-12 15:41 ` [PATCH 6/9] mm/damon/tests/core-kunit: remove DAMON_MIN_REGION redefinition SeongJae Park
2025-11-12 15:41 ` [PATCH 7/9] selftests/damon/sysfs.py: merge DAMON status dumping into commitment assertion SeongJae Park
2025-11-12 15:41 ` [PATCH 8/9] Docs/mm/damon/maintainer-profile: fix a typo on mm-untable link SeongJae Park
2025-11-12 15:41 ` [PATCH 9/9] Docs/mm/damon/maintainer-profile: fix grammartical errors SeongJae Park
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