* + mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch added to mm-new branch
@ 2025-10-15 0:03 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-10-15 0:03 UTC (permalink / raw)
To: mm-commits, ziy, ryan.roberts, npache, lorenzo.stoakes,
liam.howlett, lance.yang, dev.jain, david, baolin.wang, baohua,
richard.weiyang, akpm
The patch titled
Subject: mm/huge_memory: Optimize old_order derivation during folio splitting
has been added to the -mm mm-new branch. Its filename is
mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.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-optimize-old_order-derivation-during-folio-splitting.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: Wei Yang <richard.weiyang@gmail.com>
Subject: mm/huge_memory: Optimize old_order derivation during folio splitting
Date: Tue, 14 Oct 2025 13:46:05 +0000
Folio splitting requires both the folio's original order (@old_order) and
the new target order (@split_order).
In the current implementation, @old_order is repeatedly retrieved using
folio_order().
However, for every iteration after the first, the folio being split is the
result of the previous split, meaning its order is already known to be
equal to the previous iteration's @split_order.
This commit optimizes the logic:
* Instead of calling folio_order(), we now set @old_order directly to
the value of @split_order from the previous iteration.
* The initial @split_order (which was previously handled by a separate
@start_order variable) is now directly used, and the redundant
@start_order variable is removed.
This change avoids unnecessary function calls and simplifies the loop
setup.
Link: https://lkml.kernel.org/r/20251014134606.22543-5-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
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 | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-optimize-old_order-derivation-during-folio-splitting
+++ a/mm/huge_memory.c
@@ -3528,8 +3528,7 @@ static int __split_unmapped_folio(struct
struct address_space *mapping, bool uniform_split)
{
bool is_anon = folio_test_anon(folio);
- int order = folio_order(folio);
- int start_order = uniform_split ? new_order : order - 1;
+ int old_order = folio_order(folio);
int split_order;
folio_clear_has_hwpoisoned(folio);
@@ -3538,10 +3537,9 @@ static int __split_unmapped_folio(struct
* split to new_order one order at a time. For uniform split,
* folio is split to new_order directly.
*/
- for (split_order = start_order;
+ for (split_order = uniform_split ? new_order : old_order - 1;
split_order >= new_order;
split_order--) {
- int old_order = folio_order(folio);
int new_folios = 1UL << (old_order - split_order);
/* order-1 anonymous folio is not supported */
@@ -3576,6 +3574,7 @@ static int __split_unmapped_folio(struct
mod_mthp_stat(split_order, MTHP_STAT_NR_ANON, new_folios);
}
folio = page_folio(split_at);
+ old_order = split_order;
}
return 0;
_
Patches currently in -mm which might be from richard.weiyang@gmail.com are
mm-compaction-check-the-range-to-pageblock_pfn_to_page-is-within-the-zone-first.patch
mm-compaction-fix-the-range-to-pageblock_pfn_to_page.patch
mm-huge_memory-add-pmd-folio-to-ds_queue-in-do_huge_zero_wp_pmd.patch
mm-khugepaged-unify-pmd-folio-installation-with-map_anon_folio_pmd.patch
mm-huge_memory-only-get-folio_order-once-during-__folio_split.patch
mm-huge_memory-cache-folio-attribute-in-__split_unmapped_folio.patch
mm-huge_memory-update-folio-stat-after-successful-split.patch
mm-huge_memory-optimize-and-simplify-folio-stat-update-after-split.patch
mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch
mm-huge_memory-remove-redundant-split_order-=-new_order-check-in-uniform_split.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch added to mm-new branch
@ 2025-10-22 21:45 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2025-10-22 21:45 UTC (permalink / raw)
To: mm-commits, ziy, ryan.roberts, npache, lorenzo.stoakes, lianux.mm,
liam.howlett, lance.yang, dev.jain, david, baolin.wang, baohua,
richard.weiyang, akpm
The patch titled
Subject: mm/huge_memory: optimize old_order derivation during folio splitting
has been added to the -mm mm-new branch. Its filename is
mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.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-optimize-old_order-derivation-during-folio-splitting.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: Wei Yang <richard.weiyang@gmail.com>
Subject: mm/huge_memory: optimize old_order derivation during folio splitting
Date: Tue, 21 Oct 2025 21:21:42 +0000
Folio splitting requires both the folio's original order (@old_order) and
the new target order (@split_order).
In the current implementation, @old_order is repeatedly retrieved using
folio_order().
However, for every iteration after the first, the folio being split is the
result of the previous split, meaning its order is already known to be
equal to the previous iteration's @split_order.
This commit optimizes the logic:
* Instead of calling folio_order(), we now set @old_order directly to
the value of @split_order from the previous iteration.
This change avoids unnecessary function calls and simplifies the loop
setup.
Also it removes a check for non-existent case, since for uniform splitting
we only do split when @split_order == @new_order.
Link: https://lkml.kernel.org/r/20251021212142.25766-5-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: wang lian <lianux.mm@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
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 | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-optimize-old_order-derivation-during-folio-splitting
+++ a/mm/huge_memory.c
@@ -3607,8 +3607,8 @@ static int __split_unmapped_folio(struct
struct address_space *mapping, bool uniform_split)
{
const bool is_anon = folio_test_anon(folio);
- int order = folio_order(folio);
- int start_order = uniform_split ? new_order : order - 1;
+ int old_order = folio_order(folio);
+ int start_order = uniform_split ? new_order : old_order - 1;
int split_order;
folio_clear_has_hwpoisoned(folio);
@@ -3620,14 +3620,11 @@ static int __split_unmapped_folio(struct
for (split_order = start_order;
split_order >= new_order;
split_order--) {
- int old_order = folio_order(folio);
int nr_new_folios = 1UL << (old_order - split_order);
/* order-1 anonymous folio is not supported */
if (is_anon && split_order == 1)
continue;
- if (uniform_split && split_order != new_order)
- continue;
if (mapping) {
/*
@@ -3654,7 +3651,13 @@ static int __split_unmapped_folio(struct
mod_mthp_stat(old_order, MTHP_STAT_NR_ANON, -1);
mod_mthp_stat(split_order, MTHP_STAT_NR_ANON, nr_new_folios);
}
+ /*
+ * If uniform split, the process is complete.
+ * If non-uniform, continue splitting the folio at @split_at
+ * as long as the next @split_order is >= @new_order.
+ */
folio = page_folio(split_at);
+ old_order = split_order;
}
return 0;
_
Patches currently in -mm which might be from richard.weiyang@gmail.com are
mm-compaction-check-the-range-to-pageblock_pfn_to_page-is-within-the-zone-first.patch
mm-compaction-fix-the-range-to-pageblock_pfn_to_page.patch
mm-huge_memory-add-pmd-folio-to-ds_queue-in-do_huge_zero_wp_pmd.patch
mm-khugepaged-unify-pmd-folio-installation-with-map_anon_folio_pmd.patch
mm-huge_memory-only-get-folio_order-once-during-__folio_split.patch
mm-huge_memory-avoid-reinvoking-folio_test_anon.patch
mm-huge_memory-update-folio-stat-after-successful-split.patch
mm-huge_memory-optimize-and-simplify-folio-stat-update-after-split.patch
mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-10-22 21:45 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-10-15 0:03 + mm-huge_memory-optimize-old_order-derivation-during-folio-splitting.patch added to mm-new branch Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2025-10-22 21:45 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.