Commit 8515efbe authored by John Snow's avatar John Snow Committed by Kevin Wolf
Browse files

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: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1429314609-29776-7-git-send-email-jsnow@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 592fdd02

util/hbitmap.c

+4 −0
Original line number Diff line number Diff line
@@ -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);

    }