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Support for prefetching a static list of ROM files 

The ROM prefetcher service can be used to prefetch complete ROM files,
which is handy when using the iso9660 server (which normally reads file
content block-wise on demand). The server used to perform the
prefetching upon request of the respective ROM session. This patch adds
a facility for prefetching a predefined list of files. It is primarily
intended for eagerly fetching live-CD content in the background after
having passed the first boot stage.
This commit is contained in:
Norman Feske 2012-02-08 19:35:25 +01:00
parent b11bbd30c2
commit b8f88c035a
1 changed files with 45 additions and 19 deletions
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64
os/src/server/rom_prefetcher/main.cc
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@ -20,34 +20,35 @@
#include <base/printf.h>
#include <base/env.h>
#include <base/sleep.h>
#include <os/config.h>
volatile int dummy;
static void prefetch_dataspace(Genode::Dataspace_capability ds)
{
char *mapped = Genode::env()->rm_session()->attach(ds);
Genode::size_t size = Genode::Dataspace_client(ds).size();
/*
* Modify global volatile 'dummy' variable to prevent the compiler
* from removing the prefetch loop.
*/
enum { PREFETCH_STEP = 4096 };
for (Genode::size_t i = 0; i < size; i += PREFETCH_STEP)
dummy += mapped[i];
Genode::env()->rm_session()->detach(mapped);
}
class Rom_session_component : public Genode::Rpc_object<Genode::Rom_session>
{
private:
Genode::Rom_connection _rom;
enum { _PREFETCH_STEP = 4096 };
void _prefetch_dataspace(Genode::Dataspace_capability ds)
{
char *mapped = Genode::env()->rm_session()->attach(ds);
Genode::size_t size = Genode::Dataspace_client(ds).size();
/*
* Modify global volatile 'dummy' variable to prevent the compiler
* from removing the prefetch loop.
*/
for (Genode::size_t i = 0; i < size; i += _PREFETCH_STEP)
dummy += mapped[i];
Genode::env()->rm_session()->detach(mapped);
}
public:
/**
@ -57,7 +58,7 @@ class Rom_session_component : public Genode::Rpc_object<Genode::Rom_session>
*/
Rom_session_component(const char *filename) : _rom(filename)
{
_prefetch_dataspace(_rom.dataspace());
prefetch_dataspace(_rom.dataspace());
}
/***************************
@ -105,6 +106,31 @@ int main(int argc, char **argv)
/* connection to capability service needed to create capabilities */
static Cap_connection cap;
/*
* Prefetch ROM files specified in the config
*/
try {
Genode::Xml_node entry = config()->xml_node().sub_node("rom");
for (;;) {
enum { NAME_MAX_LEN = 64 };
char name[NAME_MAX_LEN];
name[0] = 0;
entry.attribute("name").value(name, sizeof(name));
try {
Rom_connection rom(name);
PINF("prefetching ROM file %s", name);
prefetch_dataspace(rom.dataspace());
} catch (...) {
PERR("could not open ROM file %s", name);
}
/* proceed with next XML node */
entry = entry.next("rom");
}
} catch (...) { }
static Sliced_heap sliced_heap(env()->ram_session(),
env()->rm_session());