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authorJohn Snow <jsnow@redhat.com>2015-04-17 19:49:54 -0400
committerKevin Wolf <kwolf@redhat.com>2015-04-28 15:36:10 +0200
commit8515efbef1759b9143f06e9722c8f4e145032181 (patch)
treed7058da418daf26e724613e2e515b8b816e10945 /util
parent592fdd02ae987a439a2ba25a2a973673f1484805 (diff)
hbitmap: cache array lengths
As a convenience: between incremental backups, bitmap migrations and bitmap persistence we seem to need to recalculate these a lot. Because the lengths are a little bit-twiddly, let's just solidly cache them and be done with it. Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-7-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'util')
-rw-r--r--util/hbitmap.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/util/hbitmap.c b/util/hbitmap.c
index ab139717f5..5b78613400 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -90,6 +90,9 @@ struct HBitmap {
* bitmap will still allocate HBITMAP_LEVELS arrays.
*/
unsigned long *levels[HBITMAP_LEVELS];
+
+ /* The length of each levels[] array. */
+ uint64_t sizes[HBITMAP_LEVELS];
};
/* Advance hbi to the next nonzero word and return it. hbi->pos
@@ -384,6 +387,7 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity)
hb->granularity = granularity;
for (i = HBITMAP_LEVELS; i-- > 0; ) {
size = MAX((size + BITS_PER_LONG - 1) >> BITS_PER_LEVEL, 1);
+ hb->sizes[i] = size;
hb->levels[i] = g_new0(unsigned long, size);
}