backup: Use Bitmap to replace "s->bitmap"

"s->bitmap" tracks done sectors, we only check bit states without using any
iterator which HBitmap is good for. Switch to "Bitmap" which is simpler and
more memory efficient.

Meanwhile, rename it to done_bitmap, to reflect the intention.

Signed-off-by: Fam Zheng <[email protected]>
Reviewed-by: John Snow <[email protected]>
Message-id: 1457412306[email protected]
Signed-off-by: Max Reitz <[email protected]>

diff --git a/block/backup.c b/block/backup.c
index 0f1b1bc084aab0fa27105e3473a51322df7d22f2..ab3e345e92696b08df7c774bb8fbe59fd0eec16e 100644 (file)
--- a/block/backup.c
+++ b/block/backup.c
@@ -20,6 +20,7 @@
 #include "qapi/qmp/qerror.h"
 #include "qemu/ratelimit.h"
 #include "sysemu/block-backend.h"
+#include "qemu/bitmap.h"
 
 #define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16)
 #define SLICE_TIME 100000000ULL /* ns */
@@ -42,7 +43,7 @@ typedef struct BackupBlockJob {
     BlockdevOnError on_target_error;
     CoRwlock flush_rwlock;
     uint64_t sectors_read;
-    HBitmap *bitmap;
+    unsigned long *done_bitmap;
     int64_t cluster_size;
     QLIST_HEAD(, CowRequest) inflight_reqs;
 } BackupBlockJob;
@@ -116,7 +117,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs,
     cow_request_begin(&cow_request, job, start, end);
 
     for (; start < end; start++) {
-        if (hbitmap_get(job->bitmap, start)) {
+        if (test_bit(start, job->done_bitmap)) {
             trace_backup_do_cow_skip(job, start);
             continue; /* already copied */
         }
@@ -167,7 +168,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs,
             goto out;
         }
 
-        hbitmap_set(job->bitmap, start, 1);
+        set_bit(start, job->done_bitmap);
 
         /* Publish progress, guest I/O counts as progress too.  Note that the
          * offset field is an opaque progress value, it is not a disk offset.
@@ -399,7 +400,7 @@ static void coroutine_fn backup_run(void *opaque)
     start = 0;
     end = DIV_ROUND_UP(job->common.len, job->cluster_size);
 
-    job->bitmap = hbitmap_alloc(end, 0);
+    job->done_bitmap = bitmap_new(end);
 
     bdrv_set_enable_write_cache(target, true);
     if (target->blk) {
@@ -480,7 +481,7 @@ static void coroutine_fn backup_run(void *opaque)
     /* wait until pending backup_do_cow() calls have completed */
     qemu_co_rwlock_wrlock(&job->flush_rwlock);
     qemu_co_rwlock_unlock(&job->flush_rwlock);
-    hbitmap_free(job->bitmap);
+    g_free(job->done_bitmap);
 
     if (target->blk) {
         blk_iostatus_disable(target->blk);