[Qemu-devel] [PATCH v17 3/9] Add cache handling functions

[Orit Wasserman <owasserm@redhat.com>]

Add LRU page cache mechanism.
The page are accessed by their address.

Signed-off-by: Benoit Hudzia <benoit.hudzia@sap.com>
Signed-off-by: Petter Svard <petters@cs.umu.se>
Signed-off-by: Aidan Shribman <aidan.shribman@sap.com>
Signed-off-by: Orit Wasserman <owasserm@redhat.com>
---
 Makefile.objs |    1 +
 cutils.c      |    9 +++++++++
 qemu-common.h |   13 +++++++++++++
 3 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/Makefile.objs b/Makefile.objs
index 5ebbcfa..e0fb69b 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -77,6 +77,7 @@ common-obj-y += qemu-char.o #aio.o
 common-obj-y += block-migration.o iohandler.o
 common-obj-y += pflib.o
 common-obj-y += bitmap.o bitops.o
+common-obj-y += page_cache.o
 
 common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o migration-fd.o
 common-obj-$(CONFIG_WIN32) += version.o
diff --git a/cutils.c b/cutils.c
index e2bc1b8..b0bdd4b 100644
--- a/cutils.c
+++ b/cutils.c
@@ -375,3 +375,12 @@ int qemu_parse_fd(const char *param)
     }
     return fd;
 }
+
+/* round down to the nearest power of 2*/
+int64_t pow2floor(int64_t value)
+{
+    if (!is_power_of_2(value)) {
+        value = 0x8000000000000000ULL >> clz64(value);
+    }
+    return value;
+}
diff --git a/qemu-common.h b/qemu-common.h
index 09676f5..195bab5 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -1,3 +1,4 @@
+
 /* Common header file that is included by all of qemu.  */
 #ifndef QEMU_COMMON_H
 #define QEMU_COMMON_H
@@ -411,6 +412,18 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
 /* Round number up to multiple */
 #define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
 
+static inline bool is_power_of_2(int64_t value)
+{
+    if (!value) {
+        return 0;
+    }
+
+    return !(value & (value - 1));
+}
+
+/* round down to the nearest power of 2*/
+int64_t pow2floor(int64_t value);
+
 #include "module.h"
 
 #endif
-- 
1.7.7.6