+ mm-mglru-promote-mapped-executable-folios-after-first-usage.patch added to mm-new branch
Andrew Morton <[email protected]>
| Newsgroups | org.kernel.vger.mm-commits |
|---|---|
| Message-ID | <[email protected]> |
The patch titled
Subject: mm: mglru: promote mapped executable folios after first usage
has been added to the -mm mm-new branch. Its filename is
mm-mglru-promote-mapped-executable-folios-after-first-usage.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-promote-mapped-executable-folios-after-first-usage.patch
This patch will later appear in the mm-new branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews. Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.
The mm-new branch of mm.git is not included in linux-next
If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next
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------------------------------------------------------
From: Baolin Wang <[email protected]>
Subject: mm: mglru: promote mapped executable folios after first usage
Date: Mon, 20 Jul 2026 19:12:02 +0800
Classical LRU protects mapped executable file folios through commit
8cab4754d24a0 ("vmscan: make mapped executable pages the first class
citizen") and commit c909e99364c8 ("vmscan: activate executable pages
after first usage"), giving executable code a better chance to stay in
memory, avoiding IO thrashing and improving workload performance.
However, MGLRU's protection of mapped executable file folios is less
reliable. Although shrink_folio_list() checks references, the access flag
of mapped executable file folios may have already been checked and cleared
by lru_gen_look_around() or walk_mm(). Additionally, folio_update_gen()
or lru_gen_set_refs() only sets the 'PG_referenced' flag for mapped
executable file folios, which causes shrink_folio_list() to ignore the
first usage of these mapped executable file folios and reclaim them
easily.
Follow the classical LRU's logic, promoting mapped executable file folios
after their first usage in folio_update_gen() and lru_gen_set_refs(),
giving executable code a better chance to stay in memory.
On my 32-core Arm machine, with the memcg limit set to 2G, running 'make
-j32' to build kernel showed some improvement in sys time.
base patched
9248.543s 7861.579s
Link: https://lore.kernel.org/f57d94b1d85bb3d620d89bb739128f0d929bf9c6.1784509721.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Reviewed-by: Axel Rasmussen <[email protected]>
Cc: Barry Song <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Harry Yoo <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Yuanchu Xie <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
mm/vmscan.c | 43 +++++++++++++++++++++++++++----------------
1 file changed, 27 insertions(+), 16 deletions(-)
--- a/mm/vmscan.c~mm-mglru-promote-mapped-executable-folios-after-first-usage
+++ a/mm/vmscan.c
@@ -841,10 +841,16 @@ enum folio_references {
* with PG_active set. In contrast, the aging (page table walk) path uses
* folio_update_gen().
*/
-static bool lru_gen_set_refs(struct folio *folio)
+static bool lru_gen_set_refs(struct folio *folio, const vma_flags_t *vma_flags)
{
/* see the comment on LRU_REFS_FLAGS */
if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
+ /* Activate file-backed executable folios after first usage. */
+ if (is_exec_file_folio(folio, vma_flags)) {
+ set_mask_bits(&folio->flags.f, LRU_REFS_FLAGS, BIT(PG_workingset));
+ return true;
+ }
+
set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
return false;
}
@@ -857,7 +863,7 @@ static bool lru_gen_set_refs(struct foli
return true;
}
#else
-static bool lru_gen_set_refs(struct folio *folio)
+static bool lru_gen_set_refs(struct folio *folio, const vma_flags_t *vma_flags)
{
return false;
}
@@ -892,7 +898,7 @@ static enum folio_references folio_check
if (!referenced_ptes)
return FOLIOREF_RECLAIM;
- return lru_gen_set_refs(folio) ? FOLIOREF_ACTIVATE : FOLIOREF_KEEP;
+ return lru_gen_set_refs(folio, &vma_flags) ? FOLIOREF_ACTIVATE : FOLIOREF_KEEP;
}
referenced_folio = folio_test_clear_referenced(folio);
@@ -3196,14 +3202,19 @@ static bool positive_ctrl_err(struct ctr
******************************************************************************/
/* promote pages accessed through page tables */
-static int folio_update_gen(struct folio *folio, int gen)
+static int folio_update_gen(struct folio *folio, int gen, const vma_flags_t *vma_flags)
{
unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f);
VM_WARN_ON_ONCE(gen >= MAX_NR_GENS);
- /* see the comment on LRU_REFS_FLAGS */
- if (!folio_test_referenced(folio) && !folio_test_workingset(folio)) {
+ /*
+ * See the comment on LRU_REFS_FLAGS, and activate file-backed
+ * executable folios after first usage to avoid typical IO
+ * thrashing from reclaiming.
+ */
+ if (!folio_test_referenced(folio) && !folio_test_workingset(folio) &&
+ !is_exec_file_folio(folio, vma_flags)) {
set_mask_bits(&folio->flags.f, LRU_REFS_MASK, BIT(PG_referenced));
return -1;
}
@@ -3436,8 +3447,8 @@ static bool suitable_to_scan(int total,
return young * n >= total;
}
-static void walk_update_folio(struct lru_gen_mm_walk *walk, struct folio *folio,
- int new_gen, bool dirty)
+static void walk_update_folio(struct lru_gen_mm_walk *walk, struct vm_area_struct *vma,
+ struct folio *folio, int new_gen, bool dirty)
{
int old_gen;
@@ -3450,10 +3461,10 @@ static void walk_update_folio(struct lru
folio_mark_dirty(folio);
if (walk) {
- old_gen = folio_update_gen(folio, new_gen);
+ old_gen = folio_update_gen(folio, new_gen, &vma->flags);
if (old_gen >= 0 && old_gen != new_gen)
update_batch_size(walk, folio, old_gen, new_gen);
- } else if (lru_gen_set_refs(folio)) {
+ } else if (lru_gen_set_refs(folio, &vma->flags)) {
old_gen = folio_lru_gen(folio);
if (old_gen >= 0 && old_gen != new_gen)
folio_activate(folio);
@@ -3526,7 +3537,7 @@ restart:
continue;
if (last != folio) {
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, args->vma, last, gen, dirty);
last = folio;
dirty = false;
@@ -3539,7 +3550,7 @@ restart:
walk->mm_stats[MM_LEAF_YOUNG] += nr;
}
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, args->vma, last, gen, dirty);
last = NULL;
if (i < PTRS_PER_PTE && get_next_vma(PMD_MASK, PAGE_SIZE, args, &start, &end))
@@ -3617,7 +3628,7 @@ static void walk_pmd_range_locked(pud_t
goto next;
if (last != folio) {
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, vma, last, gen, dirty);
last = folio;
dirty = false;
@@ -3631,7 +3642,7 @@ next:
i = i > MIN_LRU_BATCH ? 0 : find_next_bit(bitmap, MIN_LRU_BATCH, i) + 1;
} while (i <= MIN_LRU_BATCH);
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, vma, last, gen, dirty);
lazy_mmu_mode_disable();
spin_unlock(ptl);
@@ -4266,7 +4277,7 @@ bool lru_gen_look_around(struct page_vma
continue;
if (last != folio) {
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, vma, last, gen, dirty);
last = folio;
dirty = false;
@@ -4278,7 +4289,7 @@ bool lru_gen_look_around(struct page_vma
young += nr;
}
- walk_update_folio(walk, last, gen, dirty);
+ walk_update_folio(walk, vma, last, gen, dirty);
lazy_mmu_mode_disable();
_
Patches currently in -mm which might be from [email protected] are
mm-vmscan-remove-the-redundant-folioref_reclaim_clean-logic.patch
mm-vmscan-convert-folio_referenced-to-use-vma_flags_t.patch
mm-vmscan-add-a-helper-to-identify-file-backed-executable-folios.patch
mm-mglru-promote-mapped-executable-folios-after-first-usage.patch