[RFC PATCH 06/57] mm/collapse: move the smallest collapse order to collapse.h
From: Kiryl Shutsemau <hidden>
Date: 2026-08-16 22:46:30
Also in:
bpf, linux-kselftest, linux-mm, lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
From: "Kiryl Shutsemau (Meta)" <kas@kernel.org> The floor on the order a collapse will build is a property of collapse, not of khugepaged. MADV_COLLAPSE reaches the same code and is held to the same floor. Move KHUGEPAGED_MIN_MTHP_ORDER to the shared header as COLLAPSE_MIN_MTHP_ORDER. Preparation for the collapse engine, which sizes its per-window arrays from the same floor. No functional change intended. Assisted-by: Claude-Code:claude-opus-5 Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org> --- mm/collapse.h | 3 +++ mm/khugepaged.c | 6 ++---- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/collapse.h b/mm/collapse.h
index 44f52ea5bbb8..1e969292edcb 100644
--- a/mm/collapse.h
+++ b/mm/collapse.h@@ -7,6 +7,9 @@ #include <linux/pgtable.h> #include <linux/types.h> +/* The smallest order a collapse will build, and so the finest window it cuts */ +#define COLLAPSE_MIN_MTHP_ORDER 2 + enum scan_result { SCAN_FAIL, SCAN_SUCCEED,
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index eebc044a930e..f31689bf75a6 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c@@ -67,8 +67,6 @@ static DEFINE_READ_MOSTLY_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); static struct kmem_cache *mm_slot_cache __ro_after_init; -#define KHUGEPAGED_MIN_MTHP_ORDER 2 - /** * struct khugepaged_scan - cursor for scanning * @mm_head: the head of the mm list to scan
@@ -1540,8 +1538,8 @@ static enum scan_result mthp_collapse(struct mm_struct *mm, * any smaller order enabled. When at the smallest order * we must always move to the next offset. */ - if (order > KHUGEPAGED_MIN_MTHP_ORDER && - (enabled_orders & GENMASK(order - 1, 0))) { + if (order > COLLAPSE_MIN_MTHP_ORDER && + (enabled_orders & GENMASK(order - 1, 0))) { order--; continue; }
--
2.54.0