Commit 477327e1 authored by Zheng Yejian's avatar Zheng Yejian Committed by Andrew Morton
Browse files

mm/damon/vaddr: add 'nr_piece == 1' check in damon_va_evenly_split_region() 

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@kernel.org/

Link: https://lkml.kernel.org/r/20241022083927.3592237-3-zhengyejian@huaweicloud.com


Signed-off-by: default avatarZheng Yejian <zhengyejian@huaweicloud.com>
Reviewed-by: default avatarSeongJae Park <sj@kernel.org>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Ye Weihua <yeweihua4@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f3c7a1ed

mm/damon/tests/vaddr-kunit.h

+1 −0
Original line number Diff line number Diff line
@@ -300,6 +300,7 @@ static void damon_test_split_evenly(struct kunit *test) 
	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);

}

mm/damon/vaddr.c

+3 −0
Original line number Diff line number Diff line
@@ -72,6 +72,9 @@ static int damon_va_evenly_split_region(struct damon_target *t, 
	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);