* + mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch added to mm-unstable branch
@ 2025-09-19 20:19 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-09-19 20:19 UTC (permalink / raw)
To: mm-commits, willy, vbabka, surenb, shakeel.butt, rppt, riel,
mhocko, lorenzo.stoakes, liam.howlett, hughd, hannes, david,
baolin.wang, kas, akpm
The patch titled
Subject: mm/rmap: mlock large folios in try_to_unmap_one()
has been added to the -mm mm-unstable branch. Its filename is
mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-mlock-large-folios-in-try_to_unmap_one.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:
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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 the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kiryl Shutsemau <kas@kernel.org>
Subject: mm/rmap: mlock large folios in try_to_unmap_one()
Date: Fri, 19 Sep 2025 13:40:34 +0100
Currently, try_to_unmap_once() only tries to mlock small folios.
Use logic similar to folio_referenced_one() to mlock large folios: only do
this for fully mapped folios and under page table lock that protects all
page table entries.
Link: https://lkml.kernel.org/r/20250919124036.455709-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/rmap.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
--- a/mm/rmap.c~mm-rmap-mlock-large-folios-in-try_to_unmap_one
+++ a/mm/rmap.c
@@ -1870,6 +1870,7 @@ static bool try_to_unmap_one(struct foli
unsigned long nr_pages = 1, end_addr;
unsigned long pfn;
unsigned long hsz = 0;
+ int ptes = 0;
/*
* When racing against e.g. zap_pte_range() on another cpu,
@@ -1910,10 +1911,26 @@ static bool try_to_unmap_one(struct foli
*/
if (!(flags & TTU_IGNORE_MLOCK) &&
(vma->vm_flags & VM_LOCKED)) {
+ ptes++;
+ ret = false;
+
+ /* Only mlock fully mapped pages */
+ if (pvmw.pte && ptes != pvmw.nr_pages)
+ continue;
+
+ /*
+ * All PTEs must be protected by page table lock in
+ * order to mlock the page.
+ *
+ * If page table boundary has been cross, current ptl
+ * only protect part of ptes.
+ */
+ if (pvmw.flags & PVMW_PGTABLE_CROSSSED)
+ goto walk_done;
+
/* Restore the mlock which got missed */
- if (!folio_test_large(folio))
- mlock_vma_folio(folio, vma);
- goto walk_abort;
+ mlock_vma_folio(folio, vma);
+ goto walk_done;
}
if (!pvmw.pte) {
_
Patches currently in -mm which might be from kas@kernel.org are
mm-khugepaged-do-not-fail-collapse_pte_mapped_thp-on-scan_pmd_null.patch
mm-page_vma_mapped-track-if-the-page-is-mapped-across-page-table-boundary.patch
mm-rmap-fix-a-mlock-race-condition-in-folio_referenced_one.patch
mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch
mm-fault-try-to-map-the-entire-file-folio-in-finish_fault.patch
mm-rmap-improve-mlock-tracking-for-large-folios.patch
^ permalink raw reply [flat|nested] 2+ messages in thread* + mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch added to mm-unstable branch
@ 2025-09-23 21:30 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-09-23 21:30 UTC (permalink / raw)
To: mm-commits, shakeel.butt, lorenzo.stoakes, hannes, david,
baolin.wang, kas, akpm
The patch titled
Subject: mm/rmap: mlock large folios in try_to_unmap_one()
has been added to the -mm mm-unstable branch. Its filename is
mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-mlock-large-folios-in-try_to_unmap_one.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 the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kiryl Shutsemau <kas@kernel.org>
Subject: mm/rmap: mlock large folios in try_to_unmap_one()
Date: Tue, 23 Sep 2025 12:07:08 +0100
Currently, try_to_unmap_once() only tries to mlock small folios.
Use logic similar to folio_referenced_one() to mlock large folios: only do
this for fully mapped folios and under page table lock that protects all
page table entries.
Link: https://lkml.kernel.org/r/20250923110711.690639-4-kirill@shutemov.name
Signed-off-by: Kiryl Shutsemau <kas@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/rmap.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
--- a/mm/rmap.c~mm-rmap-mlock-large-folios-in-try_to_unmap_one
+++ a/mm/rmap.c
@@ -1870,6 +1870,7 @@ static bool try_to_unmap_one(struct foli
unsigned long nr_pages = 1, end_addr;
unsigned long pfn;
unsigned long hsz = 0;
+ int ptes = 0;
/*
* When racing against e.g. zap_pte_range() on another cpu,
@@ -1910,10 +1911,34 @@ static bool try_to_unmap_one(struct foli
*/
if (!(flags & TTU_IGNORE_MLOCK) &&
(vma->vm_flags & VM_LOCKED)) {
+ ptes++;
+
+ /*
+ * Set 'ret' to indicate the page cannot be unmapped.
+ *
+ * Do not jump to walk_abort immediately as additional
+ * iteration might be required to detect fully mapped
+ * folio an mlock it.
+ */
+ ret = false;
+
+ /* Only mlock fully mapped pages */
+ if (pvmw.pte && ptes != pvmw.nr_pages)
+ continue;
+
+ /*
+ * All PTEs must be protected by page table lock in
+ * order to mlock the page.
+ *
+ * If page table boundary has been cross, current ptl
+ * only protect part of ptes.
+ */
+ if (pvmw.flags & PVMW_PGTABLE_CROSSSED)
+ goto walk_done;
+
/* Restore the mlock which got missed */
- if (!folio_test_large(folio))
- mlock_vma_folio(folio, vma);
- goto walk_abort;
+ mlock_vma_folio(folio, vma);
+ goto walk_done;
}
if (!pvmw.pte) {
_
Patches currently in -mm which might be from kas@kernel.org are
mm-page_vma_mapped-track-if-the-page-is-mapped-across-page-table-boundary.patch
mm-rmap-fix-a-mlock-race-condition-in-folio_referenced_one.patch
mm-rmap-mlock-large-folios-in-try_to_unmap_one.patch
mm-fault-try-to-map-the-entire-file-folio-in-finish_fault.patch
mm-filemap-map-entire-large-folio-faultaround.patch
mm-rmap-improve-mlock-tracking-for-large-folios.patch
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