Changeset 84360 in vbox for trunk/src/VBox/Devices

Timestamp:

May 19, 2020 9:02:19 AM (5 years ago)

Author:

vboxsync

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

138049

Message:

VUSB: Restored non-minimal initial control URB extra allocation (see bugref:9716).

File:

• trunk/src/VBox/Devices/USB/VUSBUrb.cpp (modified) (1 diff)

trunk/src/VBox/Devices/USB/VUSBUrb.cpp

@@ -611 +611 @@
 /** @todo reuse these? */
     PVUSBCTRLEXTRA pExtra;
-#if 0
-    const size_t cbMax = sizeof(pExtra->Urb.abData) + sizeof(VUSBSETUP);
-#else
-    const size_t cbMax = sizeof(VUSBSETUP);
-#endif
+    /* The initial allocation tries to balance wasted memory versus the need to re-allocate
+     * the message data. Experience shows that an 8K initial allocation in practice never needs
+     * to be expanded but almost certainly wastes 4K or more memory.
+     */
+    const size_t cbMax = _2K + sizeof(VUSBSETUP);
     pExtra = (PVUSBCTRLEXTRA)RTMemAllocZ(RT_UOFFSETOF_DYN(VUSBCTRLEXTRA, Urb.abData[cbMax]));
     if (pExtra)