* + mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch added to mm-unstable branch
@ 2026-09-16 22:48 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-09-16 22:48 UTC (permalink / raw)
To: mm-commits, kas, akpm
The patch titled
Subject: mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
Subject: mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes
Date: Wed, 16 Sep 2026 10:31:30 +0100
The name says less than the bit means. A set bit means not only that the
PTE is present, but also that it passed the other checks: uffd, lazyfree,
anonymity, sharing. The PTE can be considered a collapse source.
mthp_collapse() then reads the bitmap starting at the PMD order, so the
bitmap is not specific to mTHP either.
Name it for what a set bit means, and update the comments that named it.
No functional change.
Assisted-by: LLM
Link: https://lore.kernel.org/20260916093145.4022188-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
---
mm/khugepaged.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
--- a/mm/khugepaged.c~mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes
+++ a/mm/khugepaged.c
@@ -115,8 +115,8 @@ struct collapse_control {
/* nodemask for allocation fallback */
nodemask_t alloc_nmask;
- /* Each bit represents a single occupied (!none/zero) page. */
- DECLARE_BITMAP(mthp_present_ptes, MAX_PTRS_PER_PTE);
+ /* Each bit marks a PTE the scan accepted as a collapse source */
+ DECLARE_BITMAP(eligible_ptes, MAX_PTRS_PER_PTE);
};
/**
@@ -627,7 +627,7 @@ static void collapse_control_init_scan(s
{
memset(cc->node_load, 0, sizeof(cc->node_load));
nodes_clear(cc->alloc_nmask);
- bitmap_zero(cc->mthp_present_ptes, MAX_PTRS_PER_PTE);
+ bitmap_zero(cc->eligible_ptes, MAX_PTRS_PER_PTE);
}
static void release_pte_folio(struct folio *folio)
@@ -1482,15 +1482,15 @@ static unsigned int max_order_from_offse
* mthp_collapse() consumes the bitmap that is generated during
* collapse_scan_pmd() to determine what regions and mTHP orders fit best.
*
- * Each bit in cc->mthp_present_ptes represents a single occupied (!none/zero)
- * page. We start at the PMD order and check if it is eligible for collapse;
+ * Each bit in cc->eligible_ptes marks a PTE the scan accepted as a collapse
+ * source. We start at the PMD order and check if it is eligible for collapse;
* if not, we check the left and right halves of the PTE page table we are
* examining at a lower order.
*
- * For each of these, we determine how many PTE entries are occupied in the
- * range of PTE entries we propose to collapse, then we compare this to a
- * threshold number of PTE entries which would need to be occupied for a
- * collapse to be permitted at that order (accounting for max_ptes_none).
+ * For each of these, we count the eligible PTEs in the range we propose to
+ * collapse, then we compare this to the number of eligible PTEs the range
+ * would need for a collapse to be permitted at that order (accounting for
+ * max_ptes_none).
*
* If a collapse is permitted, we attempt to collapse the PTE range into a
* mTHP.
@@ -1499,7 +1499,7 @@ static enum scan_result mthp_collapse(st
unsigned long address, int referenced, int unmapped,
struct collapse_control *cc, unsigned long enabled_orders)
{
- unsigned int nr_occupied_ptes, nr_ptes, max_ptes_none;
+ unsigned int nr_eligible_ptes, nr_ptes, max_ptes_none;
enum scan_result last_result = SCAN_FAIL;
int collapsed = 0;
bool alloc_failed = false;
@@ -1514,18 +1514,18 @@ static enum scan_result mthp_collapse(st
goto next_order;
max_ptes_none = collapse_max_ptes_none(cc, NULL, order);
- nr_occupied_ptes = bitmap_weight_from(cc->mthp_present_ptes, offset,
+ nr_eligible_ptes = bitmap_weight_from(cc->eligible_ptes, offset,
offset + nr_ptes);
/*
* Swap PTEs accepted during the scan are counted in @unmapped,
- * not in the present-PTE bitmap. Account them for the PMD-order
+ * not in cc->eligible_ptes. Account them for the PMD-order
* candidate.
*/
if (is_pmd_order(order))
- nr_occupied_ptes += unmapped;
+ nr_eligible_ptes += unmapped;
- if (nr_occupied_ptes >= nr_ptes - max_ptes_none) {
+ if (nr_eligible_ptes >= nr_ptes - max_ptes_none) {
enum scan_result ret;
collapse_address = address + offset * PAGE_SIZE;
@@ -1731,8 +1731,8 @@ static enum scan_result collapse_scan_pm
}
}
- /* Set bit for occupied pages */
- __set_bit(i, cc->mthp_present_ptes);
+ /* The scan accepted this PTE as a collapse source */
+ __set_bit(i, cc->eligible_ptes);
/*
* Record which node the original page is from and save this
* information to cc->node_load[].
_
Patches currently in -mm which might be from kas@kernel.org are
mm-huge_memory-do-not-touch-frozen-folios-in-deferred_split_isolate.patch
mm-huge_memory-dequeue-the-deferred-split-after-the-split-freeze.patch
mm-huge_memory-add-folio_reset_partially_mapped.patch
mm-khugepaged-drop-redundant-mm_struct-pin-in-madvise_collapse.patch
mm-khugepaged-count-collapses-where-khugepaged-makes-them.patch
mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
mm-collapse-add-collapseh-for-the-collapse-interface.patch
mm-collapse-state-what-a-collapse-may-do-in-the-policy.patch
mm-collapse-drop-the-collapse_possible-wrapper.patch
mm-collapse-name-the-per-table-scan-reset-for-what-it-resets.patch
mm-collapse-separate-scanning-a-pte-table-from-collapsing-it.patch
mm-collapse-open-code-collapse_single_pmd-in-its-two-callers.patch
mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch
mm-collapse-declare-the-collapse-interface-in-collapseh.patch
mm-collapse-implement-madv_collapse-in-madvisec.patch
^ permalink raw reply [flat|nested] 2+ messages in thread* + mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch added to mm-unstable branch
@ 2026-09-28 22:01 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-09-28 22:01 UTC (permalink / raw)
To: mm-commits, kas, akpm
The patch titled
Subject: mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
Subject: mm/khugepaged: rename mthp_present_ptes bitmap to eligible_ptes
Date: Mon, 28 Sep 2026 11:06:17 +0100
The name says less than the bit means. A set bit means not only that the
PTE is present, but also that it passed the other checks: uffd,
lazyfree, anonymity, sharing. The PTE can be considered a collapse
source.
mthp_collapse() then reads the bitmap starting at the PMD order, so the
bitmap is not specific to mTHP either.
Name it for what a set bit means, and update the comments that named it.
No functional change.
Link: https://lore.kernel.org/20260928100630.21870-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Assisted-by: LLM
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
---
mm/khugepaged.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
--- a/mm/khugepaged.c~mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes
+++ a/mm/khugepaged.c
@@ -115,8 +115,8 @@ struct collapse_control {
/* nodemask for allocation fallback */
nodemask_t alloc_nmask;
- /* Each bit represents a single occupied (!none/zero) page. */
- DECLARE_BITMAP(mthp_present_ptes, MAX_PTRS_PER_PTE);
+ /* Each bit marks a PTE the scan accepted as a collapse source */
+ DECLARE_BITMAP(eligible_ptes, MAX_PTRS_PER_PTE);
};
/**
@@ -627,7 +627,7 @@ static void collapse_control_init_scan(s
{
memset(cc->node_load, 0, sizeof(cc->node_load));
nodes_clear(cc->alloc_nmask);
- bitmap_zero(cc->mthp_present_ptes, MAX_PTRS_PER_PTE);
+ bitmap_zero(cc->eligible_ptes, MAX_PTRS_PER_PTE);
}
static void release_pte_folio(struct folio *folio)
@@ -1512,15 +1512,15 @@ static unsigned int max_order_from_offse
* mthp_collapse() consumes the bitmap that is generated during
* collapse_scan_pmd() to determine what regions and mTHP orders fit best.
*
- * Each bit in cc->mthp_present_ptes represents a single occupied (!none/zero)
- * page. We start at the PMD order and check if it is eligible for collapse;
+ * Each bit in cc->eligible_ptes marks a PTE the scan accepted as a collapse
+ * source. We start at the PMD order and check if it is eligible for collapse;
* if not, we check the left and right halves of the PTE page table we are
* examining at a lower order.
*
- * For each of these, we determine how many PTE entries are occupied in the
- * range of PTE entries we propose to collapse, then we compare this to a
- * threshold number of PTE entries which would need to be occupied for a
- * collapse to be permitted at that order (accounting for max_ptes_none).
+ * For each of these, we count the eligible PTEs in the range we propose to
+ * collapse, then we compare this to the number of eligible PTEs the range
+ * would need for a collapse to be permitted at that order (accounting for
+ * max_ptes_none).
*
* If a collapse is permitted, we attempt to collapse the PTE range into a
* mTHP.
@@ -1529,7 +1529,7 @@ static enum scan_result mthp_collapse(st
unsigned long address, int referenced, int unmapped,
struct collapse_control *cc, unsigned long enabled_orders)
{
- unsigned int nr_occupied_ptes, nr_ptes, max_ptes_none;
+ unsigned int nr_eligible_ptes, nr_ptes, max_ptes_none;
enum scan_result last_result = SCAN_FAIL;
int collapsed = 0;
bool alloc_failed = false;
@@ -1544,18 +1544,18 @@ static enum scan_result mthp_collapse(st
goto next_order;
max_ptes_none = collapse_max_ptes_none(cc, NULL, order);
- nr_occupied_ptes = bitmap_weight_from(cc->mthp_present_ptes, offset,
+ nr_eligible_ptes = bitmap_weight_from(cc->eligible_ptes, offset,
offset + nr_ptes);
/*
* Swap PTEs accepted during the scan are counted in @unmapped,
- * not in the present-PTE bitmap. Account them for the PMD-order
+ * not in cc->eligible_ptes. Account them for the PMD-order
* candidate.
*/
if (is_pmd_order(order))
- nr_occupied_ptes += unmapped;
+ nr_eligible_ptes += unmapped;
- if (nr_occupied_ptes >= nr_ptes - max_ptes_none) {
+ if (nr_eligible_ptes >= nr_ptes - max_ptes_none) {
enum scan_result ret;
collapse_address = address + offset * PAGE_SIZE;
@@ -1761,8 +1761,8 @@ static enum scan_result collapse_scan_pm
}
}
- /* Set bit for occupied pages */
- __set_bit(i, cc->mthp_present_ptes);
+ /* The scan accepted this PTE as a collapse source */
+ __set_bit(i, cc->eligible_ptes);
/*
* Record which node the original page is from and save this
* information to cc->node_load[].
_
Patches currently in -mm which might be from kas@kernel.org are
mm-huge_memory-do-not-touch-frozen-folios-in-deferred_split_isolate.patch
mm-huge_memory-dequeue-the-deferred-split-after-the-split-freeze.patch
mm-huge_memory-add-folio_reset_partially_mapped.patch
mm-khugepaged-drop-redundant-mm_struct-pin-in-madvise_collapse.patch
mm-khugepaged-count-collapses-where-khugepaged-makes-them.patch
mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch
mm-collapse-add-collapseh-for-the-collapse-interface.patch
mm-collapse-state-what-a-collapse-may-do-in-the-policy.patch
mm-collapse-drop-the-collapse_possible-wrapper.patch
mm-collapse-name-the-per-table-scan-reset-for-what-it-resets.patch
mm-collapse-call-collapse_file-from-collapse_single_pmd.patch
mm-collapse-separate-scanning-a-pte-table-from-collapsing-it.patch
mm-collapse-open-code-collapse_single_pmd-in-its-two-callers.patch
mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch
mm-collapse-declare-the-collapse-interface-in-collapseh.patch
mm-collapse-implement-madv_collapse-in-madvisec.patch
selftests-mm-raise-the-khugepaged-test-case-cap.patch
selftests-mm-skip-collapse_compound_extreme-where-the-pmd-is-too-large.patch
selftests-mm-scale-khugepageds-collapse-wait-with-the-pmd-size.patch
selftests-mm-skip-khugepaged-page-cache-cases-without-a-pmd-folio.patch
selftests-mm-make-the-swap-cases-swapout-reliable.patch
selftests-mm-stop-khugepaged-during-the-madv_collapse-cases.patch
selftests-mm-move-is_backed_by_folio-into-vm_util.patch
selftests-mm-add-folio-order-check-for-address-ranges.patch
selftests-mm-add-folio-order-detection-self-check.patch
selftests-mm-add-khugepaged-completion-barrier-helper.patch
selftests-mm-add-order-parameterized-khugepaged-collapse-cases.patch
selftests-mm-parameterize-the-mixed-source-collapse-case-by-source-order.patch
selftests-mm-cover-a-shared-source-collapse-write-race.patch
selftests-mm-run-every-supported-collapse-order-by-default.patch
selftests-mm-check-that-one-khugepaged-pass-collapses-one-window.patch
selftests-mm-add-khugepaged-race-harness.patch
selftests-mm-race-the-collapse-of-windows-with-holes.patch
selftests-mm-add-memory-pressure-threads-to-the-khugepaged-race-harness.patch
selftests-mm-zap-whole-pte-tables-in-the-khugepaged-race-harness.patch
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