From 93faa9a36f83fdff0b5f8b24390bdff1885e3828 Mon Sep 17 00:00:00 2001
From: Christian Prochaska <christian.prochaska@genode-labs.com>
Date: Mon, 23 Apr 2012 14:44:28 +0200
Subject: [PATCH] Config option for GDB monitor RAM preservation

This patch allows to configure the amount of RAM that GDB monitor should
preserve for itself. The configuration syntax looks as follows:

<start name="gdb_monitor">
    <resource name="RAM" quantum="1G"/>
    <config>
        <target name="noux">
        <preserve name="RAM" quantum="2M"/>
        ...
    </config>
</start>

Fixes #190.
---
 ports/run/debug_nitpicker.run           |  5 ++++-
 ports/run/gdb_monitor.run               |  5 ++++-
 ports/run/gdb_monitor_interactive.run   |  5 ++++-
 ports/run/gdb_monitor_target_config.run |  1 +
 ports/src/app/gdb_monitor/main.cc       | 19 +++++++++++++++++--
 5 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/ports/run/debug_nitpicker.run b/ports/run/debug_nitpicker.run
index ba8f495629..b1113c4468 100644
--- a/ports/run/debug_nitpicker.run
+++ b/ports/run/debug_nitpicker.run
@@ -63,7 +63,10 @@ set config {
 	<start name="gdb_monitor">
 		<resource name="RAM" quantum="4M"/>
 		<provides><service name="Nitpicker"/></provides>
-		<config><target name="nitpicker"/></config>
+		<config>
+			<target name="nitpicker"/>
+			<preserve name="RAM" quantum="2M"/>
+		</config>
 	</start>
 	<start name="scout">
 		<resource name="RAM" quantum="32M"/>
diff --git a/ports/run/gdb_monitor.run b/ports/run/gdb_monitor.run
index 05104298d8..c5e73328a0 100644
--- a/ports/run/gdb_monitor.run
+++ b/ports/run/gdb_monitor.run
@@ -59,7 +59,10 @@ set config {
 	</start>
 	<start name="gdb_monitor">
 		<resource name="RAM" quantum="4M"/>
-		<config> <target name="test-gdb_monitor" /> </config>
+		<config>
+			<target name="test-gdb_monitor"/>
+			<preserve name="RAM" quantum="2M"/>
+		</config>
 	</start>
 </config>
 }
diff --git a/ports/run/gdb_monitor_interactive.run b/ports/run/gdb_monitor_interactive.run
index 096cd25d7d..e367b746ab 100644
--- a/ports/run/gdb_monitor_interactive.run
+++ b/ports/run/gdb_monitor_interactive.run
@@ -53,7 +53,10 @@ set config {
 	</start>
 	<start name="gdb_monitor">
 		<resource name="RAM" quantum="4M"/>
-		<config> <target name="test-gdb_monitor" /> </config>
+		<config>
+			<target name="test-gdb_monitor"/>
+			<preserve name="RAM" quantum="2M"/>
+		</config>
 	</start>
 </config>
 }
diff --git a/ports/run/gdb_monitor_target_config.run b/ports/run/gdb_monitor_target_config.run
index 9dee06d983..75ac1e2a68 100644
--- a/ports/run/gdb_monitor_target_config.run
+++ b/ports/run/gdb_monitor_target_config.run
@@ -58,6 +58,7 @@ set config {
 					<test_config_subnode/>
 				</config>
 			</target>
+			<preserve name="RAM" quantum="2M"/>
 		</config>
 	</start>
 </config>
diff --git a/ports/src/app/gdb_monitor/main.cc b/ports/src/app/gdb_monitor/main.cc
index 13891388b5..eebd7a82b0 100644
--- a/ports/src/app/gdb_monitor/main.cc
+++ b/ports/src/app/gdb_monitor/main.cc
@@ -65,8 +65,23 @@ int main()
 	/* extract target node from config file */
 	Xml_node target_node = config()->xml_node().sub_node("target");
 
-	/* reserve some memory for gdb_monitor and give the rest to the child */
-	Number_of_bytes ram_quota = env()->ram_session()->avail() - 2*1024*1024;
+	/*
+	 * preserve the configured amount of memory for gdb_monitor and give the
+	 * remainder to the child
+	 */
+	Number_of_bytes preserved_ram_quota = 0;
+	try {
+		Xml_node preserve_node = config()->xml_node().sub_node("preserve");
+		if (preserve_node.attribute("name").has_value("RAM"))
+			preserve_node.attribute("quantum").value(&preserved_ram_quota);
+		else
+			throw Xml_node::Exception();
+	} catch (...) {
+		PERR("Error: could not find a valid <preserve> config node");
+		return -1;
+	}
+
+	Number_of_bytes ram_quota = env()->ram_session()->avail() - preserved_ram_quota;
 
 	/* start the application */
 	char *unique_name = filename;