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[3/6] sbitmap: don't loop twice in find_next_zero_bit()

Message ID 20230720094555.1397621-4-chengming.zhou@linux.dev (mailing list archive)
State New, archived
Headers show
Series sbitmap: fix offset hint wrap and some optimizations | expand

Commit Message

Chengming Zhou July 20, 2023, 9:45 a.m. UTC 
From: Chengming Zhou <zhouchengming@bytedance.com>

__sbitmap_get_shallow() try to allocate a free bit with a limited depth,
which always wrap when finding a free bit in the word, even in the
round-robin case. So it seems we don't need strict round-robin here.

This way will loop twice in find_next_zero_bit() in the word, no point
in looping twice in find_next_zero_bit() if we don't want strict
round-robin for this case.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 lib/sbitmap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index ccb96d1f92ba..0f3943bd3940 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -268,7 +268,9 @@  static int __sbitmap_get_shallow(struct sbitmap *sb,
 	unsigned int index;
 
 	index = SB_NR_TO_INDEX(sb, alloc_hint);
-	alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
+
+	/* No point in looping twice in find_next_zero_bit() for this case. */
+	alloc_hint = 0;
 
 	return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true);
 }