This optimizies the CPU utilization of the rb_get_bmap_range()
function when most of the bitmap is allocated.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
---
lib/ext2fs/blkmap64_rb.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/lib/ext2fs/blkmap64_rb.c b/lib/ext2fs/blkmap64_rb.c
index eb56c85..7196e90 100644
--- a/lib/ext2fs/blkmap64_rb.c
+++ b/lib/ext2fs/blkmap64_rb.c
@@ -721,6 +721,7 @@ static errcode_t rb_get_bmap_range(ext2fs_generic_bitmap bitmap,
struct rb_node *parent = NULL, *next, **n;
struct ext2fs_rb_private *bp;
struct bmap_rb_extent *ext;
+ int count;
__u64 pos;
bp = (struct ext2fs_rb_private *) bitmap->private;
@@ -748,14 +749,32 @@ static errcode_t rb_get_bmap_range(ext2fs_generic_bitmap bitmap,
ext = ext2fs_rb_entry(parent, struct bmap_rb_extent, node);
pos = ext->start;
- if (pos < start)
+ count = ext->count;
+ if (pos >= start + num)
+ break;
+ if (pos < start) {
+ count -= start - pos;
+ if (count < 0)
+ continue;
pos = start;
-
- while (pos < (ext->start + ext->count)) {
- if ((pos - start) >= num)
- return 0;
+ }
+ if (pos + count > start + num)
+ count = start + num - pos;
+
+ while (count > 0) {
+ if ((count >= 8) &&
+ ((pos - start) % 8) == 0) {
+ int nbytes = count >> 3;
+ int offset = (pos - start) >> 3;
+
+ memset(out + offset, 0xFF, nbytes);
+ pos += nbytes << 3;
+ count -= nbytes << 3;
+ continue;
+ }
ext2fs_fast_set_bit64((pos - start), out);
pos++;
+ count--;
}
}
return 0;
--
1.7.12.rc0.22.gcdd159b
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