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Support for prefetching a static list of ROM files

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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());