genode/repos/os/include/cli_monitor/ram.h

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/*
* \brief RAM management
* \author Norman Feske
* \date 2013-10-14
*/
/*
* Copyright (C) 2013-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__CLI_MONITOR__RAM_H_
#define _INCLUDE__CLI_MONITOR__RAM_H_
/* Genode includes */
#include <pd_session/client.h>
namespace Cli_monitor { class Ram; }
class Cli_monitor::Ram
{
private:
typedef Genode::size_t size_t;
Genode::Pd_session &_pd;
Genode::Pd_session_capability _pd_cap;
Genode::Lock mutable _lock;
Genode::Signal_context_capability _yield_sigh;
Genode::Signal_context_capability _resource_avail_sigh;
size_t _preserve;
void _validate_preservation()
{
if (_pd.avail_ram().value < _preserve)
Genode::Signal_transmitter(_yield_sigh).submit();
/* verify to answer outstanding resource requests too */
if (_pd.avail_ram().value > _preserve)
Genode::Signal_transmitter(_resource_avail_sigh).submit();
}
public:
struct Status
{
size_t quota, used, avail, preserve;
Status(size_t quota, size_t used, size_t avail, size_t preserve)
: quota(quota), used(used), avail(avail), preserve(preserve) { }
};
Ram(Genode::Pd_session &pd,
Genode::Pd_session_capability pd_cap,
size_t preserve,
Genode::Signal_context_capability yield_sigh,
Genode::Signal_context_capability resource_avail_sigh)
:
_pd(pd), _pd_cap(pd_cap),
_yield_sigh(yield_sigh),
_resource_avail_sigh(resource_avail_sigh),
_preserve(preserve)
{ }
size_t preserve() const
{
Genode::Lock::Guard guard(_lock);
return _preserve;
}
void preserve(size_t preserve)
{
Genode::Lock::Guard guard(_lock);
_preserve = preserve;
_validate_preservation();
}
Status status() const
{
Genode::Lock::Guard guard(_lock);
return Status(_pd.ram_quota().value, _pd.used_ram().value,
_pd.avail_ram().value, _preserve);
}
void validate_preservation()
{
Genode::Lock::Guard guard(_lock);
_validate_preservation();
}
/**
* Exception type
*/
class Transfer_quota_failed { };
/**
* \throw Transfer_quota_failed
*/
void withdraw_from(Genode::Ram_session_capability from, size_t amount)
{
using namespace Genode;
Lock::Guard guard(_lock);
try { Pd_session_client(from).transfer_quota(_pd_cap, Ram_quota{amount}); }
catch (...) { throw Transfer_quota_failed(); }
Signal_transmitter(_resource_avail_sigh).submit();
}
/**
* \throw Transfer_quota_failed
*/
void transfer_to(Genode::Ram_session_capability to, size_t amount)
{
Genode::Lock::Guard guard(_lock);
if (_pd.avail_ram().value < (_preserve + amount)) {
Genode::Signal_transmitter(_yield_sigh).submit();
throw Transfer_quota_failed();
}
try { _pd.transfer_quota(to, Genode::Ram_quota{amount}); }
catch (...) { throw Transfer_quota_failed(); }
}
size_t avail() const { return _pd.avail_ram().value; }
};
#endif /* _INCLUDE__CLI_MONITOR__RAM_H_ */