The patch titled
Subject: mm/huge_memory: add folio_split() to debugfs testing interface.
has been added to the -mm mm-unstable branch. Its filename is
mm-huge_memory-add-folio_split-to-debugfs-testing-interface.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-add-folio_split-to-debugfs-testing-interface.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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------------------------------------------------------
From: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/huge_memory: add folio_split() to debugfs testing interface.
Date: Tue, 4 Feb 2025 22:14:15 -0500
This allows to test folio_split() by specifying an additional in folio
page offset parameter to split_huge_page debugfs interface.
Link: https://lkml.kernel.org/r/20250205031417.1771278-6-ziy@xxxxxxxxxx
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickens <hughd@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Kirill A. Shuemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: linmiaohe <linmiaohe@xxxxxxxxxx>
Cc: Mattew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 47 ++++++++++++++++++++++++++++++++-------------
1 file changed, 34 insertions(+), 13 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-add-folio_split-to-debugfs-testing-interface
+++ a/mm/huge_memory.c
@@ -4293,7 +4293,8 @@ static inline bool vma_not_suitable_for_
}
static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
- unsigned long vaddr_end, unsigned int new_order)
+ unsigned long vaddr_end, unsigned int new_order,
+ long in_folio_offset)
{
int ret = 0;
struct task_struct *task;
@@ -4377,8 +4378,16 @@ static int split_huge_pages_pid(int pid,
if (!folio_test_anon(folio) && folio->mapping != mapping)
goto unlock;
- if (!split_folio_to_order(folio, target_order))
- split++;
+ if (in_folio_offset < 0 ||
+ in_folio_offset >= folio_nr_pages(folio)) {
+ if (!split_folio_to_order(folio, target_order))
+ split++;
+ } else {
+ struct page *split_at = folio_page(folio,
+ in_folio_offset);
+ if (!folio_split(folio, target_order, split_at, NULL))
+ split++;
+ }
unlock:
@@ -4401,7 +4410,8 @@ out:
}
static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
- pgoff_t off_end, unsigned int new_order)
+ pgoff_t off_end, unsigned int new_order,
+ long in_folio_offset)
{
struct filename *file;
struct file *candidate;
@@ -4450,8 +4460,15 @@ static int split_huge_pages_in_file(cons
if (folio->mapping != mapping)
goto unlock;
- if (!split_folio_to_order(folio, target_order))
- split++;
+ if (in_folio_offset < 0 || in_folio_offset >= nr_pages) {
+ if (!split_folio_to_order(folio, target_order))
+ split++;
+ } else {
+ struct page *split_at = folio_page(folio,
+ in_folio_offset);
+ if (!folio_split(folio, target_order, split_at, NULL))
+ split++;
+ }
unlock:
folio_unlock(folio);
@@ -4484,6 +4501,7 @@ static ssize_t split_huge_pages_write(st
int pid;
unsigned long vaddr_start, vaddr_end;
unsigned int new_order = 0;
+ long in_folio_offset = -1;
ret = mutex_lock_interruptible(&split_debug_mutex);
if (ret)
@@ -4512,30 +4530,33 @@ static ssize_t split_huge_pages_write(st
goto out;
}
- ret = sscanf(tok_buf, "0x%lx,0x%lx,%d", &off_start,
- &off_end, &new_order);
- if (ret != 2 && ret != 3) {
+ ret = sscanf(tok_buf, "0x%lx,0x%lx,%d,%ld", &off_start, &off_end,
+ &new_order, &in_folio_offset);
+ if (ret != 2 && ret != 3 && ret != 4) {
ret = -EINVAL;
goto out;
}
- ret = split_huge_pages_in_file(file_path, off_start, off_end, new_order);
+ ret = split_huge_pages_in_file(file_path, off_start, off_end,
+ new_order, in_folio_offset);
if (!ret)
ret = input_len;
goto out;
}
- ret = sscanf(input_buf, "%d,0x%lx,0x%lx,%d", &pid, &vaddr_start, &vaddr_end, &new_order);
+ ret = sscanf(input_buf, "%d,0x%lx,0x%lx,%d,%ld", &pid, &vaddr_start,
+ &vaddr_end, &new_order, &in_folio_offset);
if (ret == 1 && pid == 1) {
split_huge_pages_all();
ret = strlen(input_buf);
goto out;
- } else if (ret != 3 && ret != 4) {
+ } else if (ret != 3 && ret != 4 && ret != 5) {
ret = -EINVAL;
goto out;
}
- ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end, new_order);
+ ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end, new_order,
+ in_folio_offset);
if (!ret)
ret = strlen(input_buf);
out:
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
selftests-mm-make-file-backed-thp-split-work-by-writing-pmd-size-data.patch
mm-huge_memory-allow-split-shmem-large-folio-to-any-lower-order.patch
selftests-mm-test-splitting-file-backed-thp-to-any-lower-order.patch
mm-huge_memory-add-two-new-not-yet-used-functions-for-folio_split.patch
mm-huge_memory-move-folio-split-common-code-to-__folio_split.patch
mm-huge_memory-add-buddy-allocator-like-folio_split.patch
mm-huge_memory-remove-the-old-unused-__split_huge_page.patch
mm-huge_memory-add-folio_split-to-debugfs-testing-interface.patch
mm-truncate-use-buddy-allocator-like-folio-split-for-truncate-operation.patch
selftests-mm-add-tests-for-folio_split-buddy-allocator-like-split.patch
