On 07/24/2018 07:17 AM, Leonid Bloch wrote:
Signed-off-by: Leonid Bloch <lbl...@janustech.com>
---
docs/qcow2-cache.txt | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
index a0a1267482..43c0faaddb 100644
--- a/docs/qcow2-cache.txt
+++ b/docs/qcow2-cache.txt
@@ -110,11 +110,12 @@ How to configure the cache sizes
Cache sizes can be configured using the -drive option in the
command-line, or the 'blockdev-add' QMP command.
-There are three options available, and all of them take bytes:
+There are four options available:
-"l2-cache-size": maximum size of the L2 table cache
-"refcount-cache-size": maximum size of the refcount block cache
-"cache-size": maximum size of both caches combined
+"l2-cache-size": maximum size of the L2 table cache (bytes, K, M)
+"refcount-cache-size": maximum size of the refcount block cache (bytes, K, M)
+"cache-size": maximum size of both caches combined (bytes, K, M)
+"l2-cache-full": make the L2 cache cover the full image (boolean)
There are a few things that need to be taken into account:
Worth mentioning that the first three can be combined (although usually
you'll never specify more than 2; as specifying all 3 requires that you
perform the correct addition), but that the third is mutually exclusive?
@@ -130,6 +131,9 @@ 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.
+- If "l2-cache-full" is specified, QEMU will assign enough memory
+ to the L2 cache to cover the entire size of the image.
+
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
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
