* + mm-huge_memory-refactor-after-split-page-cache-code.patch added to mm-new branch
@ 2025-07-16 21:03 Andrew Morton
0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2025-07-16 21:03 UTC (permalink / raw)
To: mm-commits, ryan.roberts, npache, lorenzo.stoakes, liam.howlett,
k.shutemov, hughd, dev.jain, david, dan.carpenter, baolin.wang,
baohua, antonio, ziy, akpm
The patch titled
Subject: mm/huge_memory: refactor after-split (page) cache code.
has been added to the -mm mm-new branch. Its filename is
mm-huge_memory-refactor-after-split-page-cache-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-refactor-after-split-page-cache-code.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.
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: Zi Yan <ziy@nvidia.com>
Subject: mm/huge_memory: refactor after-split (page) cache code.
Date: Wed, 16 Jul 2025 13:11:12 -0400
Smatch/coverity checkers report NULL mapping referencing issues[1][2][3]
every time the code is modified, because they do not understand that
mapping cannot be NULL when a folio is in page cache in the code.
Refactor the code to make it explicit.
No functional change is intended.
[1]https://lore.kernel.org/linux-mm/2afe3d59-aca5-40f7-82a3-a6d976fb0f4f@stanley.mountain/
[2]https://lore.kernel.org/oe-kbuild/64b54034-f311-4e7d-b935-c16775dbb642@suswa.mountain/
[3]https://lore.kernel.org/linux-mm/20250716145804.4836-1-antonio@mandelbit.com/
Link: https://lkml.kernel.org/r/20250716171112.3666150-1-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Antonio Quartulli <antonio@mandelbit.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <k.shutemov@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/huge_memory.c | 43 ++++++++++++++++++++++++++++---------------
1 file changed, 28 insertions(+), 15 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-refactor-after-split-page-cache-code
+++ a/mm/huge_memory.c
@@ -3804,6 +3804,8 @@ static int __folio_split(struct folio *f
*/
for (new_folio = folio_next(folio); new_folio != next_folio;
new_folio = next) {
+ unsigned long nr_pages = folio_nr_pages(new_folio);
+
next = folio_next(new_folio);
expected_refs = folio_expected_ref_count(new_folio) + 1;
@@ -3811,25 +3813,36 @@ static int __folio_split(struct folio *f
lru_add_split_folio(folio, new_folio, lruvec, list);
- /* Some pages can be beyond EOF: drop them from cache */
- if (new_folio->index >= end) {
- if (shmem_mapping(mapping))
- nr_shmem_dropped += folio_nr_pages(new_folio);
- else if (folio_test_clear_dirty(new_folio))
- folio_account_cleaned(
- new_folio,
- inode_to_wb(mapping->host));
- __filemap_remove_folio(new_folio, NULL);
- folio_put_refs(new_folio,
- folio_nr_pages(new_folio));
- } else if (mapping) {
- __xa_store(&mapping->i_pages, new_folio->index,
- new_folio, 0);
- } else if (swap_cache) {
+ /*
+ * Anonymous folio with swap cache.
+ * NOTE: shmem in swap cache is not supported yet.
+ */
+ if (swap_cache) {
__xa_store(&swap_cache->i_pages,
swap_cache_index(new_folio->swap),
new_folio, 0);
+ continue;
}
+
+ /* Anonymouse folio without swap cache */
+ if (!mapping)
+ continue;
+
+ /* Add the new folio to the page cache. */
+ if (new_folio->index < end) {
+ __xa_store(&mapping->i_pages, new_folio->index,
+ new_folio, 0);
+ continue;
+ }
+
+ /* Drop folio beyond EOF: ->index >= end */
+ if (shmem_mapping(mapping))
+ nr_shmem_dropped += nr_pages;
+ else if (folio_test_clear_dirty(new_folio))
+ folio_account_cleaned(
+ new_folio, inode_to_wb(mapping->host));
+ __filemap_remove_folio(new_folio, NULL);
+ folio_put_refs(new_folio, nr_pages);
}
/*
* Unfreeze @folio only after all page cache entries, which
_
Patches currently in -mm which might be from ziy@nvidia.com are
selftests-mm-fix-split_huge_page_test-for-folio_split-tests.patch
mm-huge_memory-move-unrelated-code-out-of-__split_unmapped_folio.patch
mm-huge_memory-use-folio_expected_ref_count-to-calculate-ref_count.patch
mm-huge_memory-refactor-after-split-page-cache-code.patch
^ permalink raw reply [flat|nested] 3+ messages in thread
* + mm-huge_memory-refactor-after-split-page-cache-code.patch added to mm-new branch
@ 2025-07-18 21:12 Andrew Morton
0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2025-07-18 21:12 UTC (permalink / raw)
To: mm-commits, ryan.roberts, npache, matthew.brost, lorenzo.stoakes,
liam.howlett, k.shutemov, hughd, dev.jain, david, dan.carpenter,
baolin.wang, baohua, balbirs, ziy, akpm
The patch titled
Subject: mm/huge_memory: refactor after-split (page) cache code
has been added to the -mm mm-new branch. Its filename is
mm-huge_memory-refactor-after-split-page-cache-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-refactor-after-split-page-cache-code.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.
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: Zi Yan <ziy@nvidia.com>
Subject: mm/huge_memory: refactor after-split (page) cache code
Date: Fri, 18 Jul 2025 14:37:20 -0400
Smatch/coverity checkers report NULL mapping referencing issues[1][2][3]
every time the code is modified, because they do not understand that
mapping cannot be NULL when a folio is in page cache in the code.
Refactor the code to make it explicit.
Remove "end = -1" for anonymous folios, since after code refactoring, end
is no longer used by anonymous folio handling code.
No functional change is intended.
[1]https://lore.kernel.org/linux-mm/2afe3d59-aca5-40f7-82a3-a6d976fb0f4f@stanley.mountain/
[2]https://lore.kernel.org/oe-kbuild/64b54034-f311-4e7d-b935-c16775dbb642@suswa.mountain/
[3]https://lore.kernel.org/linux-mm/20250716145804.4836-1-antonio@mandelbit.com/
Link: https://lkml.kernel.org/r/20250718183720.4054515-7-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <k.shutemov@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/huge_memory.c | 44 ++++++++++++++++++++++++++++----------------
1 file changed, 28 insertions(+), 16 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-refactor-after-split-page-cache-code
+++ a/mm/huge_memory.c
@@ -3640,7 +3640,6 @@ static int __folio_split(struct folio *f
ret = -EBUSY;
goto out;
}
- end = -1;
mapping = NULL;
anon_vma_lock_write(anon_vma);
} else {
@@ -3793,6 +3792,8 @@ static int __folio_split(struct folio *f
*/
for (new_folio = folio_next(folio); new_folio != end_folio;
new_folio = next) {
+ unsigned long nr_pages = folio_nr_pages(new_folio);
+
next = folio_next(new_folio);
expected_refs = folio_expected_ref_count(new_folio) + 1;
@@ -3800,25 +3801,36 @@ static int __folio_split(struct folio *f
lru_add_split_folio(folio, new_folio, lruvec, list);
- /* Some pages can be beyond EOF: drop them from cache */
- if (new_folio->index >= end) {
- if (shmem_mapping(mapping))
- nr_shmem_dropped += folio_nr_pages(new_folio);
- else if (folio_test_clear_dirty(new_folio))
- folio_account_cleaned(
- new_folio,
- inode_to_wb(mapping->host));
- __filemap_remove_folio(new_folio, NULL);
- folio_put_refs(new_folio,
- folio_nr_pages(new_folio));
- } else if (mapping) {
- __xa_store(&mapping->i_pages, new_folio->index,
- new_folio, 0);
- } else if (swap_cache) {
+ /*
+ * Anonymous folio with swap cache.
+ * NOTE: shmem in swap cache is not supported yet.
+ */
+ if (swap_cache) {
__xa_store(&swap_cache->i_pages,
swap_cache_index(new_folio->swap),
new_folio, 0);
+ continue;
}
+
+ /* Anonymous folio without swap cache */
+ if (!mapping)
+ continue;
+
+ /* Add the new folio to the page cache. */
+ if (new_folio->index < end) {
+ __xa_store(&mapping->i_pages, new_folio->index,
+ new_folio, 0);
+ continue;
+ }
+
+ /* Drop folio beyond EOF: ->index >= end */
+ if (shmem_mapping(mapping))
+ nr_shmem_dropped += nr_pages;
+ else if (folio_test_clear_dirty(new_folio))
+ folio_account_cleaned(
+ new_folio, inode_to_wb(mapping->host));
+ __filemap_remove_folio(new_folio, NULL);
+ folio_put_refs(new_folio, nr_pages);
}
/*
* Unfreeze @folio only after all page cache entries, which
_
Patches currently in -mm which might be from ziy@nvidia.com are
selftests-mm-fix-split_huge_page_test-for-folio_split-tests.patch
mm-huge_memory-move-unrelated-code-out-of-__split_unmapped_folio.patch
mm-huge_memory-remove-after_split-label-in-__split_unmapped_folio.patch
mm-huge_memory-deduplicate-code-in-__folio_split.patch
mm-huge_memory-convert-vm_bug-to-vm_warn-in-__folio_split.patch
mm-huge_memory-get-frozen-folio-refcount-with-folio_expected_ref_count.patch
mm-huge_memory-refactor-after-split-page-cache-code.patch
^ permalink raw reply [flat|nested] 3+ messages in thread
* + mm-huge_memory-refactor-after-split-page-cache-code.patch added to mm-new branch
@ 2025-07-20 0:47 Andrew Morton
0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2025-07-20 0:47 UTC (permalink / raw)
To: mm-commits, ryan.roberts, npache, matthew.brost, lorenzo.stoakes,
liam.howlett, k.shutemov, hughd, dev.jain, david, dan.carpenter,
baolin.wang, baohua, balbirs, ziy, akpm
The patch titled
Subject: mm/huge_memory: refactor after-split (page) cache code
has been added to the -mm mm-new branch. Its filename is
mm-huge_memory-refactor-after-split-page-cache-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-refactor-after-split-page-cache-code.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.
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: Zi Yan <ziy@nvidia.com>
Subject: mm/huge_memory: refactor after-split (page) cache code
Date: Thu, 17 Jul 2025 22:30:00 -0400
Smatch/coverity checkers report NULL mapping referencing issues[1][2][3]
every time the code is modified, because they do not understand that
mapping cannot be NULL when a folio is in page cache in the code.
Refactor the code to make it explicit.
Remove "end = -1" for anonymous folios, since after code refactoring, end
is no longer used by anonymous folio handling code.
No functional change is intended.
Link: https://lkml.kernel.org/r/20250718023000.4044406-7-ziy@nvidia.com
Link: https://lore.kernel.org/linux-mm/2afe3d59-aca5-40f7-82a3-a6d976fb0f4f@stanley.mountain/ [1]
Link: https://lore.kernel.org/oe-kbuild/64b54034-f311-4e7d-b935-c16775dbb642@suswa.mountain/ [2]
Link: https://lore.kernel.org/linux-mm/20250716145804.4836-1-antonio@mandelbit.com/ [3]
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <k.shutemov@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/huge_memory.c | 44 ++++++++++++++++++++++++++++----------------
1 file changed, 28 insertions(+), 16 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-refactor-after-split-page-cache-code
+++ a/mm/huge_memory.c
@@ -3646,7 +3646,6 @@ static int __folio_split(struct folio *f
ret = -EBUSY;
goto out;
}
- end = -1;
mapping = NULL;
anon_vma_lock_write(anon_vma);
} else {
@@ -3799,6 +3798,8 @@ static int __folio_split(struct folio *f
*/
for (new_folio = folio_next(folio); new_folio != end_folio;
new_folio = next) {
+ unsigned long nr_pages = folio_nr_pages(new_folio);
+
next = folio_next(new_folio);
expected_refs = folio_expected_ref_count(new_folio) + 1;
@@ -3806,25 +3807,36 @@ static int __folio_split(struct folio *f
lru_add_split_folio(folio, new_folio, lruvec, list);
- /* Some pages can be beyond EOF: drop them from cache */
- if (new_folio->index >= end) {
- if (shmem_mapping(mapping))
- nr_shmem_dropped += folio_nr_pages(new_folio);
- else if (folio_test_clear_dirty(new_folio))
- folio_account_cleaned(
- new_folio,
- inode_to_wb(mapping->host));
- __filemap_remove_folio(new_folio, NULL);
- folio_put_refs(new_folio,
- folio_nr_pages(new_folio));
- } else if (mapping) {
- __xa_store(&mapping->i_pages, new_folio->index,
- new_folio, 0);
- } else if (swap_cache) {
+ /*
+ * Anonymous folio with swap cache.
+ * NOTE: shmem in swap cache is not supported yet.
+ */
+ if (swap_cache) {
__xa_store(&swap_cache->i_pages,
swap_cache_index(new_folio->swap),
new_folio, 0);
+ continue;
}
+
+ /* Anonymous folio without swap cache */
+ if (!mapping)
+ continue;
+
+ /* Add the new folio to the page cache. */
+ if (new_folio->index < end) {
+ __xa_store(&mapping->i_pages, new_folio->index,
+ new_folio, 0);
+ continue;
+ }
+
+ /* Drop folio beyond EOF: ->index >= end */
+ if (shmem_mapping(mapping))
+ nr_shmem_dropped += nr_pages;
+ else if (folio_test_clear_dirty(new_folio))
+ folio_account_cleaned(
+ new_folio, inode_to_wb(mapping->host));
+ __filemap_remove_folio(new_folio, NULL);
+ folio_put_refs(new_folio, nr_pages);
}
/*
* Unfreeze @folio only after all page cache entries, which
_
Patches currently in -mm which might be from ziy@nvidia.com are
selftests-mm-fix-split_huge_page_test-for-folio_split-tests.patch
mm-huge_memory-move-unrelated-code-out-of-__split_unmapped_folio.patch
mm-huge_memory-remove-after_split-label-in-__split_unmapped_folio.patch
mm-huge_memory-deduplicate-code-in-__folio_split.patch
mm-huge_memory-convert-vm_bug-to-vm_warn-in-__folio_split.patch
mm-huge_memory-get-frozen-folio-refcount-with-folio_expected_ref_count.patch
mm-huge_memory-refactor-after-split-page-cache-code.patch
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-07-20 0:47 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-07-18 21:12 + mm-huge_memory-refactor-after-split-page-cache-code.patch added to mm-new branch Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2025-07-20 0:47 Andrew Morton
2025-07-16 21:03 Andrew Morton
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.