@@ -130,6 +130,9 @@ There are a few things that need to be taken into account:
memory as possible to the L2 cache before increasing the refcount
cache size.
+ - At most two of "l2-cache-size", "refcount-cache-size", and "cache-size"
+ can be set simultaneously.
+
Unlike L2 tables, refcount blocks are not used during normal I/O but
only during allocations and internal snapshots. In most cases they are
accessed sequentially (even during random guest I/O) so increasing the
@@ -752,15 +752,18 @@ image file)
@item cache-size
The maximum total size of the L2 table and refcount block caches in bytes
-(default: 1048576 bytes or 8 clusters, whichever is larger)
+(default: the sum of l2-cache-size and refcount-cache-size)
@item l2-cache-size
The maximum size of the L2 table cache in bytes
-(default: 4/5 of the total cache size)
+(default: if cache-size is not defined - 1048576 bytes or 8 clusters, whichever
+is larger; otherwise, as large as possible or needed within the cache-size,
+while permitting the requested or the minimal refcount cache size)
@item refcount-cache-size
The maximum size of the refcount block cache in bytes
-(default: 1/5 of the total cache size)
+(default: 4 times the cluster size; or if cache-size is specified, the part of
+it which is not used for the L2 cache)
@item cache-clean-interval
Clean unused entries in the L2 and refcount caches. The interval is in seconds.
Signed-off-by: Leonid Bloch <lbloch@janustech.com> --- docs/qcow2-cache.txt | 3 +++ qemu-options.hx | 9 ++++++--- 2 files changed, 9 insertions(+), 3 deletions(-)