[Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

[Anthony PERARD <anthony.perard@citrix.com>]

The code_gen_buffer is not use by Xen and can be really big (several
GB). Even if the host RAM is not used, this buffer just burn the address
space of the QEMU process.

So to "avoid" this allocation, the asked tb_size is set to the minimum.

The other way to do that would be to not call code_gen_alloc when Xen is
enabled.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 vl.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/vl.c b/vl.c
index d8c7c01..bd60a89 100644
--- a/vl.c
+++ b/vl.c
@@ -3106,6 +3106,14 @@ int main(int argc, char **argv, char **envp)
         }
     }
 
+    if (xen_enabled()) {
+        /* Allocate only the minimum amount of memory for the code_gen_buffer.
+         * Xen does not use it and we need the virtual address space for the
+         * MapCache.
+         */
+        tb_size = 1;
+    }
+
     /* init the dynamic translator */
     cpu_exec_init_all(tb_size * 1024 * 1024);
 
-- 
Anthony PERARD