Changeset 38657 in vbox

Timestamp:

Sep 6, 2011 2:06:56 PM (13 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

73869

Message:

VD+VDI: Implement optimization for discard to avoid reading the complete data all the time and bug fixes

Location:

trunk/src/VBox/Storage

Files:

• VD.cpp (modified) (9 diffs)
• VDI.cpp (modified) (6 diffs)

trunk/src/VBox/Storage/VD.cpp

@@ -1010 +1010 @@
     int rc = VINF_SUCCESS;
 
+    LogFlowFunc(("pDisk=%#p pDiscard=%#p cbDiscardingNew=%zu\n",
+                 pDisk, pDiscard, cbDiscardingNew));
+
     while (pDiscard->cbDiscarding > cbDiscardingNew)
     {
@@ -1021 +1024 @@
         size_t cbLeft = pBlock->cbDiscard;
         bool fAllocated = ASMBitTest(pBlock->pbmAllocated, idxStart);
-        uint32_t cSectors = pBlock->cbDiscard * 8;
+        uint32_t cSectors = pBlock->cbDiscard / 512;
 
         while (cbLeft > 0)
@@ -1073 +1076 @@
     Assert(RT_FAILURE(rc) || pDiscard->cbDiscarding <= cbDiscardingNew);
 
+    LogFlowFunc(("returns rc=%Rrc\n", rc));
     return rc;
 }
@@ -1127 +1131 @@
             /* Clip range to remain in the current block. */
             if (pBlockAbove)
-                cbThisDiscard = RT_MIN(cbDiscard, pBlockAbove->Core.Key - (offStart + cbDiscard - 1));
+                cbThisDiscard = RT_MIN(cbDiscard, pBlockAbove->Core.KeyLast - offStart + 1);
             else
                 cbThisDiscard = cbDiscard;
 
-            Assert(cbThisDiscard % 512 == 0);
+            Assert(!(cbThisDiscard % 512));
 
             /* No block found, try to discard using the backend first. */
@@ -1144 +1148 @@
                 if (pBlock)
                 {
-                    pBlock->Core.Key     = offStart + cbPreAllocated;
-                    pBlock->Core.KeyLast = offStart + cbThisDiscard + cbPreAllocated - 1;
-                    pBlock->cbDiscard    = cbThisDiscard;
+                    pBlock->Core.Key     = offStart - cbPreAllocated;
+                    pBlock->Core.KeyLast = offStart + cbThisDiscard + cbPostAllocated - 1;
+                    pBlock->cbDiscard    = cbPreAllocated + cbThisDiscard + cbPostAllocated;
                     pBlock->pbmAllocated = pbmAllocated;
                     bool fInserted = RTAvlrU64Insert(pDiscard->pTreeBlocks, &pBlock->Core);
@@ -1165 +1169 @@
         {
             /* Range lies partly in the block, update allocation bitmap. */
-            cbThisDiscard = pBlock->Core.KeyLast - offStart + 1;
+            cbThisDiscard = RT_MIN(cbDiscard, pBlock->Core.KeyLast - offStart + 1);
             rc = VERR_VD_DISCARD_ALIGNMENT_NOT_MET;
         }
+
+        Assert(cbDiscard >= cbThisDiscard);
 
         if (rc == VERR_VD_DISCARD_ALIGNMENT_NOT_MET)
@@ -1212 +1218 @@
                 RTListNodeRemove(&pBlock->NodeLru);
                 RTListPrepend(&pDiscard->ListLru, &pBlock->NodeLru);
+                rc = VINF_SUCCESS;
             }
         }
+
+        Assert(cbDiscard >= cbThisDiscard);
 
         cbDiscard -= cbThisDiscard;
@@ -1284 +1293 @@
                 Assert(!(cbThisRange % 512));
                 Assert(!((uOffset - pBlock->Core.Key) % 512));
+
+                cbThisRange = RT_MIN(cbThisRange, pBlock->Core.KeyLast - uOffset + 1);
 
                 idxStart = (uOffset - pBlock->Core.Key) / 512;
@@ -1295 +1306 @@
                     cbThisRange = RT_MIN(cbThisRange, pBlock->Core.Key - uOffset);
             }
+
+            Assert(cbRange >= cbThisRange);
 
             uOffset += cbThisRange;

trunk/src/VBox/Storage/VDI.cpp

@@ -888 +888 @@
 
     return rc;
+}
+
+/**
+ * Internal: Creates a allocation bitmap from the given data.
+ * Sectors which contain only 0 are marked as unallocated and sectors with
+ * other data as allocated.
+ *
+ * @returns Pointer to the allocation bitmap or NULL on failure.
+ * @param   pvData    The data to create the allocation bitmap for.
+ * @param   cbData    Number of bytes in the buffer.
+ */
+static void *vdiAllocationBitmapCreate(void *pvData, size_t cbData)
+{
+    unsigned cSectors = cbData / 512;
+    unsigned uSectorCur = 0;
+    void *pbmAllocationBitmap = NULL;
+
+    Assert(!(cbData % 512));
+    Assert(!(cSectors % 8));
+
+    pbmAllocationBitmap = RTMemAllocZ(cSectors / 8);
+
+    while (uSectorCur < cSectors)
+    {
+        int idxSet = ASMBitFirstSet((uint8_t *)pvData + uSectorCur * 512, cbData * 8);
+
+        if (idxSet != -1)
+        {
+            unsigned idxSectorAlloc = idxSet / 8 / 512;
+            ASMBitSet(pbmAllocationBitmap, uSectorCur + idxSectorAlloc);
+
+            uSectorCur += idxSectorAlloc + 1;
+            cbData     -= (idxSectorAlloc + 1) * 512;
+        }
+        else
+            break;
+    }
+
+    return pbmAllocationBitmap;
 }
 
@@ -2560 +2599 @@
     Assert(!(cbDiscard % 512));
 
+    AssertMsgReturn(!(pImage->uOpenFlags & VD_OPEN_FLAGS_READONLY),
+                    ("Image is readonly\n"), VERR_VD_IMAGE_READ_ONLY);
+    AssertMsgReturn(   uOffset + cbDiscard <= getImageDiskSize(&pImage->Header)
+                    && cbDiscard,
+                    ("Invalid parameters uOffset=%llu cbDiscard=%zu\n",
+                     uOffset, cbDiscard),
+                     VERR_INVALID_PARAMETER);
+
     do
     {
@@ -2669 +2716 @@
                 rc = vdIfIoIntFileSetSize(pImage->pIfIo, pImage->pStorage, cbImage - pImage->cbTotalBlockData);
             }
-            else /* if (fDiscard & VD_DISCARD_MARK_UNUSED) */
+            else if (fDiscard & VD_DISCARD_MARK_UNUSED)
             {
                 /* Write changed data to the image. */
@@ -2675 +2722 @@
                                             pbBlockData + offDiscard, cbDiscard, NULL);
             }
-#if 0
             else
             {
@@ -2681 +2727 @@
                 *pcbPreAllocated = cbPreAllocated;
                 *pcbPostAllocated = cbPostAllocated;
-                *ppbmAllocationBitmap = vdAllocationBitmapCreate(pvBlock, getImageBlockSize(&pImage->Header));
+                *ppbmAllocationBitmap = vdiAllocationBitmapCreate(pbBlockData, getImageBlockSize(&pImage->Header));
                 if (RT_UNLIKELY(!*ppbmAllocationBitmap))
                     rc = VERR_NO_MEMORY;
@@ -2687 +2733 @@
                     rc = VERR_VD_DISCARD_ALIGNMENT_NOT_MET;
             }
-#endif
         }
         /* else: nothing to do. */