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From: John Snow <jsnow@redhat.com>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, jsnow@redhat.com,
	qemu-stable@nongnu.org, qemu-block@nongnu.org,
	Max Reitz <mreitz@redhat.com>
Subject: [Qemu-devel] [PULL 08/36] hbitmap: enable merging across granularities
Date: Fri, 16 Aug 2019 19:12:50 -0400
Message-ID: <20190816231318.8650-9-jsnow@redhat.com> (raw)
In-Reply-To: <20190816231318.8650-1-jsnow@redhat.com>

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190709232550.10724-9-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
---
 util/hbitmap.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/util/hbitmap.c b/util/hbitmap.c
index 83927f3c08a..fd44c897ab0 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -781,7 +781,27 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size)
 
 bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b)
 {
-    return (a->size == b->size) && (a->granularity == b->granularity);
+    return (a->orig_size == b->orig_size);
+}
+
+/**
+ * hbitmap_sparse_merge: performs dst = dst | src
+ * works with differing granularities.
+ * best used when src is sparsely populated.
+ */
+static void hbitmap_sparse_merge(HBitmap *dst, const HBitmap *src)
+{
+    uint64_t offset = 0;
+    uint64_t count = src->orig_size;
+
+    while (hbitmap_next_dirty_area(src, &offset, &count)) {
+        hbitmap_set(dst, offset, count);
+        offset += count;
+        if (offset >= src->orig_size) {
+            break;
+        }
+        count = src->orig_size - offset;
+    }
 }
 
 /**
@@ -812,10 +832,24 @@ bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)
         return true;
     }
 
+    if (a->granularity != b->granularity) {
+        if ((a != result) && (b != result)) {
+            hbitmap_reset_all(result);
+        }
+        if (a != result) {
+            hbitmap_sparse_merge(result, a);
+        }
+        if (b != result) {
+            hbitmap_sparse_merge(result, b);
+        }
+        return true;
+    }
+
     /* This merge is O(size), as BITS_PER_LONG and HBITMAP_LEVELS are constant.
      * It may be possible to improve running times for sparsely populated maps
      * by using hbitmap_iter_next, but this is suboptimal for dense maps.
      */
+    assert(a->size == b->size);
     for (i = HBITMAP_LEVELS - 1; i >= 0; i--) {
         for (j = 0; j < a->sizes[i]; j++) {
             result->levels[i][j] = a->levels[i][j] | b->levels[i][j];
-- 
2.21.0



  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 23:12 [Qemu-devel] [PULL 00/36] Bitmaps patches John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 01/36] qapi/block-core: Introduce BackupCommon John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 02/36] drive-backup: create do_backup_common John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 03/36] blockdev-backup: utilize do_backup_common John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 04/36] qapi: add BitmapSyncMode enum John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 05/36] block/backup: Add mirror sync mode 'bitmap' John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 06/36] block/backup: add 'never' policy to bitmap sync mode John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 07/36] hbitmap: Fix merge when b is empty, and result is not an alias of a John Snow
2019-08-16 23:12 ` John Snow [this message]
2019-08-16 23:12 ` [Qemu-devel] [PULL 09/36] block/dirty-bitmap: add bdrv_dirty_bitmap_merge_internal John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 10/36] block/dirty-bitmap: add bdrv_dirty_bitmap_get John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 11/36] block/backup: upgrade copy_bitmap to BdrvDirtyBitmap John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 12/36] block/backup: add 'always' bitmap sync policy John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 13/36] iotests: add testing shim for script-style python tests John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 14/36] iotests: teach run_job to cancel pending jobs John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 15/36] iotests: teach FilePath to produce multiple paths John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 16/36] iotests: Add virtio-scsi device helper John Snow
2019-08-16 23:12 ` [Qemu-devel] [PULL 17/36] iotests: add test 257 for bitmap-mode backups John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 18/36] block/backup: loosen restriction on readonly bitmaps John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 19/36] blockdev: reduce aio_context locked sections in bitmap add/remove John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 20/36] qapi: implement block-dirty-bitmap-remove transaction action John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 21/36] iotests: test bitmap moving inside 254 John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 22/36] iotests/257: add Pattern class John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 23/36] iotests/257: add EmulatedBitmap class John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 24/36] iotests/257: Refactor backup helpers John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 25/36] block/backup: hoist bitmap check into QMP interface John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 26/36] iotests/257: test API failures John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 27/36] block/backup: improve sync=bitmap work estimates John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 28/36] block/backup: centralize copy_bitmap initialization John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 29/36] block/backup: add backup_is_cluster_allocated John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 30/36] block/backup: teach TOP to never copy unallocated regions John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 31/36] block/backup: support bitmap sync modes for non-bitmap backups John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 32/36] iotests/257: test traditional sync modes John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 33/36] qapi: add dirty-bitmaps to query-named-block-nodes result John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 34/36] block/backup: deal with zero detection John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 35/36] block/backup: refactor write_flags John Snow
2019-08-16 23:13 ` [Qemu-devel] [PULL 36/36] tests/test-hbitmap: test next_zero and _next_dirty_area after truncate John Snow
2019-08-19 11:32 ` [Qemu-devel] [PULL 00/36] Bitmaps patches Peter Maydell

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