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[Qemu-devel] [PATCH v2 04/23] memory: merge adjacent segments of a singl
From: |
Avi Kivity |
Subject: |
[Qemu-devel] [PATCH v2 04/23] memory: merge adjacent segments of a single memory region |
Date: |
Tue, 26 Jul 2011 14:26:03 +0300 |
Simple implementations of memory routers, for example the Cirrus VGA memory
banks
or the 440FX PAM registers can generate adjacent memory regions which are
contiguous.
Detect these and merge them; this saves kvm memory slots and shortens lookup
times.
Signed-off-by: Avi Kivity <address@hidden>
---
memory.c | 29 +++++++++++++++++++++++++++++
1 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/memory.c b/memory.c
index d858b47..121f9e1 100644
--- a/memory.c
+++ b/memory.c
@@ -122,6 +122,34 @@ static void flatview_destroy(FlatView *view)
qemu_free(view->ranges);
}
+static bool can_merge(FlatRange *r1, FlatRange *r2)
+{
+ return addrrange_end(r1->addr) == r2->addr.start
+ && r1->mr == r2->mr
+ && r1->offset_in_region + r1->addr.size == r2->offset_in_region
+ && r1->dirty_log_mask == r2->dirty_log_mask;
+}
+
+/* Attempt to simplify a view by merging ajacent ranges */
+static void flatview_simplify(FlatView *view)
+{
+ unsigned i, j;
+
+ i = 0;
+ while (i < view->nr) {
+ j = i + 1;
+ while (j < view->nr
+ && can_merge(&view->ranges[j-1], &view->ranges[j])) {
+ view->ranges[i].addr.size += view->ranges[j].addr.size;
+ ++j;
+ }
+ ++i;
+ memmove(&view->ranges[i], &view->ranges[j],
+ (view->nr - j) * sizeof(view->ranges[j]));
+ view->nr -= j - i;
+ }
+}
+
/* Render a memory region into the global view. Ranges in @view obscure
* ranges in @mr.
*/
@@ -209,6 +237,7 @@ static FlatView generate_memory_topology(MemoryRegion *mr)
flatview_init(&view);
render_memory_region(&view, mr, 0, addrrange_make(0, UINT64_MAX));
+ flatview_simplify(&view);
return view;
}
--
1.7.5.3
[Qemu-devel] [PATCH v2 03/23] memory: implement dirty tracking, Avi Kivity, 2011/07/26
[Qemu-devel] [PATCH v2 10/23] memory: add backward compatibility for old portio registration, Avi Kivity, 2011/07/26
[Qemu-devel] [PATCH v2 17/23] pc: grab system_memory, Avi Kivity, 2011/07/26
[Qemu-devel] [PATCH v2 08/23] memory: late initialization of ram_addr, Avi Kivity, 2011/07/26