The patch titled
Subject: mm/damon/vaddr: Add 'nr_piece == 1' check in damon_va_evenly_split_region()
has been added to the -mm mm-unstable branch. Its filename is
mm-damon-vaddr-add-nr_piece-==-1-check-in-damon_va_evenly_split_region.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-vaddr-add-nr_piece-==-1-check-in-damon_va_evenly_split_region.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: Zheng Yejian <zhengyejian@xxxxxxxxxxxxxxx>
Subject: mm/damon/vaddr: Add 'nr_piece == 1' check in damon_va_evenly_split_region()
Date: Tue, 22 Oct 2024 16:39:27 +0800
As discussed in [1], damon_va_evenly_split_region() is called to
size-evenly split a region into 'nr_pieces' small regions,
when nr_pieces == 1, no actual split is required. Check that case
for better code readability and add a simple kunit testcase.
[1] https://lore.kernel.org/all/20241021163316.12443-1-sj@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/20241022083927.3592237-3-zhengyejian@xxxxxxxxxxxxxxx
Signed-off-by: Zheng Yejian <zhengyejian@xxxxxxxxxxxxxxx>
Reviewed-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: Fernand Sieber <sieberf@xxxxxxxxxx>
Cc: Leonard Foerster <foersleo@xxxxxxxxx>
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Ye Weihua <yeweihua4@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/tests/vaddr-kunit.h | 1 +
mm/damon/vaddr.c | 3 +++
2 files changed, 4 insertions(+)
--- a/mm/damon/tests/vaddr-kunit.h~mm-damon-vaddr-add-nr_piece-==-1-check-in-damon_va_evenly_split_region
+++ a/mm/damon/tests/vaddr-kunit.h
@@ -300,6 +300,7 @@ static void damon_test_split_evenly(stru
damon_test_split_evenly_fail(test, 0, 100, 0);
damon_test_split_evenly_succ(test, 0, 100, 10);
damon_test_split_evenly_succ(test, 5, 59, 5);
+ damon_test_split_evenly_succ(test, 4, 6, 1);
damon_test_split_evenly_succ(test, 0, 3, 2);
damon_test_split_evenly_fail(test, 5, 6, 2);
}
--- a/mm/damon/vaddr.c~mm-damon-vaddr-add-nr_piece-==-1-check-in-damon_va_evenly_split_region
+++ a/mm/damon/vaddr.c
@@ -72,6 +72,9 @@ static int damon_va_evenly_split_region(
if (!r || !nr_pieces)
return -EINVAL;
+ if (nr_pieces == 1)
+ return 0;
+
orig_end = r->ar.end;
sz_orig = damon_sz_region(r);
sz_piece = ALIGN_DOWN(sz_orig / nr_pieces, DAMON_MIN_REGION);
_
Patches currently in -mm which might be from zhengyejian@xxxxxxxxxxxxxxx are
mm-damon-vaddr-fix-issue-in-damon_va_evenly_split_region.patch
mm-damon-vaddr-add-nr_piece-==-1-check-in-damon_va_evenly_split_region.patch
