genode/repos/os/include/cli_monitor/child.h
Norman Feske e91170a49c app/cli_monitor: API transition
Besides updating CLI monitor to the new API, the patch removes
Fiasco.OC-specific extensions that remained unused for a long time.

Ref #1987
2017-01-13 13:07:00 +01:00

329 lines
8.7 KiB
C++

/*
* \brief Child handling
* \author Norman Feske
* \date 2013-10-05
*/
/*
* Copyright (C) 2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__CLI_MONITOR__CHILD_H_
#define _INCLUDE__CLI_MONITOR__CHILD_H_
/* Genode includes */
#include <util/list.h>
#include <base/registry.h>
#include <base/child.h>
#include <init/child_policy.h>
#include <os/child_policy_dynamic_rom.h>
#include <cpu_session/connection.h>
#include <pd_session/connection.h>
#include <base/session_label.h>
/* CLI-monitor includes */
#include <cli_monitor/ram.h>
namespace Cli_monitor { class Child_base; }
class Cli_monitor::Child_base : public Genode::Child_policy
{
public:
/*
* XXX derive donated quota from information to be provided by
* the used 'Connection' interfaces
*/
enum { DONATED_RAM_QUOTA = 128*1024 };
class Quota_exceeded : public Genode::Exception { };
typedef Genode::size_t size_t;
typedef Genode::Registered<Genode::Parent_service> Parent_service;
typedef Genode::Registry<Parent_service> Parent_services;
private:
Ram &_ram;
Genode::Session_label const _label;
Binary_name const _binary_name;
Genode::Ram_session_capability _ref_ram_cap;
Genode::Ram_session &_ref_ram;
size_t _ram_quota;
size_t _ram_limit;
Parent_services _parent_services;
enum { ENTRYPOINT_STACK_SIZE = 12*1024 };
Genode::Rpc_entrypoint _entrypoint;
Genode::Child_policy_dynamic_rom_file _config_policy;
/**
* If set to true, immediately withdraw resources yielded by the child
*/
bool _withdraw_on_yield_response = false;
/**
* Arguments of current resource request from the child
*/
Genode::Parent::Resource_args _resource_args;
Genode::Signal_context_capability _yield_response_sigh_cap;
Genode::Signal_context_capability _exit_sig_cap;
/* true if child is scheduled for destruction */
bool _exited = false;
Genode::Child _child;
public:
/**
* Constructor
*
* \param ref_ram used as reference account for the child'd RAM
* session and for allocating the backing store
* for the child's configuration
*/
Child_base(Ram &ram,
Name const &label,
Binary_name const &binary_name,
Genode::Pd_session &pd_session,
Genode::Ram_session &ref_ram,
Genode::Ram_session_capability ref_ram_cap,
Genode::Region_map &local_rm,
Genode::size_t ram_quota,
Genode::size_t ram_limit,
Genode::Signal_context_capability yield_response_sig_cap,
Genode::Signal_context_capability exit_sig_cap)
:
_ram(ram),
_label(label), _binary_name(binary_name),
_ref_ram_cap(ref_ram_cap), _ref_ram(ref_ram),
_ram_quota(ram_quota), _ram_limit(ram_limit),
_entrypoint(&pd_session, ENTRYPOINT_STACK_SIZE, _label.string(), false),
_config_policy("config", _entrypoint, &ref_ram),
_yield_response_sigh_cap(yield_response_sig_cap),
_exit_sig_cap(exit_sig_cap),
_child(local_rm, _entrypoint, *this)
{ }
Genode::Session_label label() const { return _label; }
void configure(char const *config, size_t config_len)
{
_config_policy.load(config, config_len);
}
void start()
{
_entrypoint.activate();
}
/**
* Issue yield request to the child
*/
void yield(size_t amount, bool greedy)
{
if (requested_ram_quota())
return; /* resource request in flight */
char buf[128];
Genode::snprintf(buf, sizeof(buf), "ram_quota=%ld", amount);
_withdraw_on_yield_response = greedy;
_child.yield(buf);
}
/**
* Return amount of RAM currently requested by the child
*/
size_t requested_ram_quota() const
{
return Genode::Arg_string::find_arg(_resource_args.string(), "ram_quota").ulong_value(0);
}
/**
* Withdraw quota from the child
*
* \throw Ram::Transfer_quota_failed
*/
void withdraw_ram_quota(size_t amount)
{
if (!amount)
return;
_ram.withdraw_from(_child.ram_session_cap(), amount);
_ram_quota -= amount;
}
/**
* Upgrade quota of child
*
* \throw Ram::Transfer_quota_failed
*/
void upgrade_ram_quota(size_t amount)
{
_ram.transfer_to(_child.ram_session_cap(), amount);
_ram_quota += amount;
/* wake up child if resource request is in flight */
size_t const req = requested_ram_quota();
if (req && _child.ram().avail() >= req) {
_child.notify_resource_avail();
/* clear request state */
_resource_args = Genode::Parent::Resource_args("");
}
}
/**
* Try to respond to a current resource request issued by the child
*
* This method evaluates the conditions, under which a resource
* request can be answered: There must be enough room between the
* current quota and the configured limit, and there must be enough
* slack memory available. If both conditions are met, the quota
* of the child gets upgraded.
*/
void try_response_to_resource_request()
{
size_t const req = requested_ram_quota();
if (!req)
return; /* no resource request in flight */
/*
* Respond to the current request if the requested quota fits
* within the limit and if there is enough free quota available.
*/
if (req <= _ram.status().avail && req + _ram_quota <= _ram_limit) {
try { upgrade_ram_quota(req); }
catch (Ram::Transfer_quota_failed) { }
}
}
/**
* Set limit for on-demand RAM quota expansion
*/
void ram_limit(size_t limit)
{
_ram_limit = limit;
try_response_to_resource_request();
}
struct Ram_status
{
size_t quota = 0, limit = 0, xfer = 0, used = 0, avail = 0, req = 0;
Ram_status() { }
Ram_status(size_t quota, size_t limit, size_t xfer, size_t used,
size_t avail, size_t req)
:
quota(quota), limit(limit), xfer(xfer), used(used),
avail(avail), req(req)
{ }
};
/**
* Return RAM quota status of the child
*
* XXX should be a const method, but the 'Ram_session' accessors
* are not const
*/
Ram_status ram_status()
{
return Ram_status(_ram_quota,
_ram_limit,
_ram_quota - _child.ram().quota(),
_child.ram().used(),
_child.ram().avail(),
requested_ram_quota());
}
/**
* Return true if child exited and should be destructed
*/
bool exited() const { return _exited; }
/****************************
** Child_policy interface **
****************************/
Name name() const override { return _label; }
Binary_name binary_name() const override { return _binary_name; }
Genode::Ram_session_capability ref_ram_cap() const override { return _ref_ram_cap; }
Genode::Ram_session &ref_ram() override { return _ref_ram; }
void init(Genode::Ram_session &session, Genode::Ram_session_capability cap) override
{
session.ref_account(_ref_ram_cap);
_ref_ram.transfer_quota(cap, _ram_quota);
}
Genode::Service &resolve_session_request(Genode::Service::Name const &name,
Genode::Session_state::Args const &args) override
{
Genode::Service *service = nullptr;
/* check for config file request */
if ((service = _config_policy.resolve_session_request(name.string(), args.string())))
return *service;
/* populate session-local parent service registry on demand */
_parent_services.for_each([&] (Parent_service &s) {
if (s.name() == name)
service = &s; });
if (service)
return *service;
return *new (Genode::env()->heap()) Parent_service(_parent_services, name);
}
void yield_response()
{
if (_withdraw_on_yield_response) {
enum { RESERVE = 4*1024*1024 };
size_t amount = _child.ram().avail() < RESERVE
? 0 : _child.ram().avail() - RESERVE;
/* try to immediately withdraw freed-up resources */
try { withdraw_ram_quota(amount); }
catch (Ram::Transfer_quota_failed) { }
}
/* propagate yield-response signal */
Genode::Signal_transmitter(_yield_response_sigh_cap).submit();
}
void resource_request(Genode::Parent::Resource_args const &args)
{
_resource_args = args;
try_response_to_resource_request();
}
void exit(int exit_value) override
{
Genode::log("subsystem \"", name(), "\" exited with value ", exit_value);
_exited = true;
/* trigger destruction of the child */
Genode::Signal_transmitter(_exit_sig_cap).submit();
}
};
#endif /* _INCLUDE__CLI_MONITOR__CHILD_H_ */