356 lines
9.6 KiB
C++
356 lines
9.6 KiB
C++
/*
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* \brief Child handling
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* \author Norman Feske
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* \date 2013-10-05
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*/
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/*
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* Copyright (C) 2013-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__CLI_MONITOR__CHILD_H_
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#define _INCLUDE__CLI_MONITOR__CHILD_H_
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/* Genode includes */
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#include <util/list.h>
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#include <base/registry.h>
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#include <base/child.h>
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#include <init/child_policy.h>
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#include <os/child_policy_dynamic_rom.h>
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#include <cpu_session/connection.h>
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#include <pd_session/connection.h>
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#include <base/session_label.h>
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/* CLI-monitor includes */
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#include <cli_monitor/ram.h>
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namespace Cli_monitor { class Child_base; }
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class Cli_monitor::Child_base : public Genode::Child_policy
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{
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public:
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/*
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* XXX derive donated quota from information to be provided by
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* the used 'Connection' interfaces
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*/
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enum { DONATED_RAM_QUOTA = 128*1024 };
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class Quota_exceeded : public Genode::Exception { };
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typedef Genode::size_t size_t;
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typedef Genode::Cap_quota Cap_quota;
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typedef Genode::Registered<Genode::Parent_service> Parent_service;
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private:
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Genode::Env &_env;
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Ram &_ram;
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Genode::Allocator &_alloc;
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Genode::Session_label const _label;
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Binary_name const _binary_name;
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Genode::Pd_session_capability _ref_pd_cap;
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Genode::Pd_session &_ref_pd;
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Cap_quota _cap_quota;
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size_t _ram_quota;
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size_t _ram_limit;
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struct Parent_services : Genode::Registry<Parent_service>
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{
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Genode::Allocator &_alloc;
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Parent_services(Genode::Allocator &alloc) : _alloc(alloc) { }
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~Parent_services()
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{
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for_each([&] (Parent_service &s) { Genode::destroy(_alloc, &s); });
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}
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} _parent_services { _alloc };
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enum { ENTRYPOINT_STACK_SIZE = 12*1024 };
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Genode::Rpc_entrypoint _entrypoint;
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Genode::Child_policy_dynamic_rom_file _config_policy;
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/**
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* If set to true, immediately withdraw resources yielded by the child
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*/
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bool _withdraw_on_yield_response = false;
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/**
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* Arguments of current resource request from the child
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*/
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Genode::Parent::Resource_args _resource_args { };
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Genode::Signal_context_capability _yield_response_sigh_cap;
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Genode::Signal_context_capability _exit_sig_cap;
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/* true if child is scheduled for destruction */
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bool _exited = false;
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Genode::Child _child;
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Genode::Service &_matching_service(Genode::Service::Name const &name,
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Genode::Session_label const &label)
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{
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Genode::Service *service = nullptr;
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/* check for config file request */
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if ((service = _config_policy.resolve_session_request(name, label)))
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return *service;
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/* populate session-local parent service registry on demand */
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_parent_services.for_each([&] (Parent_service &s) {
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if (s.name() == name)
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service = &s; });
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if (service)
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return *service;
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return *new (_alloc) Parent_service(_parent_services, _env, name);
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}
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public:
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/**
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* Constructor
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*
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* \param ref_ram used as reference account for the child'd RAM
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* session and for allocating the backing store
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* for the child's configuration
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* \param alloc allocator used to fill parent-service registry
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* on demand
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*/
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Child_base(Genode::Env &env,
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Ram &ram,
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Genode::Allocator &alloc,
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Name const &label,
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Binary_name const &binary_name,
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Genode::Pd_session &ref_pd,
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Genode::Pd_session_capability ref_pd_cap,
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Genode::Region_map &local_rm,
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Cap_quota cap_quota,
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Genode::size_t ram_quota,
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Genode::size_t ram_limit,
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Genode::Signal_context_capability yield_response_sig_cap,
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Genode::Signal_context_capability exit_sig_cap)
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:
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_env(env), _ram(ram), _alloc(alloc),
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_label(label), _binary_name(binary_name),
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_ref_pd_cap (ref_pd_cap), _ref_pd (ref_pd),
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_cap_quota(cap_quota), _ram_quota(ram_quota), _ram_limit(ram_limit),
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_entrypoint(&ref_pd, ENTRYPOINT_STACK_SIZE, _label.string(), false),
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_config_policy(local_rm, "config", _entrypoint, &_env.ram()),
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_yield_response_sigh_cap(yield_response_sig_cap),
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_exit_sig_cap(exit_sig_cap),
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_child(local_rm, _entrypoint, *this)
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{ }
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Genode::Session_label label() const { return _label; }
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void configure(char const *config, size_t config_len)
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{
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_config_policy.load(config, config_len);
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}
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void start()
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{
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_entrypoint.activate();
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}
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/**
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* Issue yield request to the child
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*/
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void yield(size_t amount, bool greedy)
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{
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if (requested_ram_quota())
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return; /* resource request in flight */
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char buf[128];
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Genode::snprintf(buf, sizeof(buf), "ram_quota=%ld", amount);
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_withdraw_on_yield_response = greedy;
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_child.yield(buf);
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}
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/**
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* Return amount of RAM currently requested by the child
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*/
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size_t requested_ram_quota() const
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{
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return Genode::Arg_string::find_arg(_resource_args.string(), "ram_quota").ulong_value(0);
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}
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/**
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* Withdraw quota from the child
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*
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* \throw Ram::Transfer_quota_failed
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*/
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void withdraw_ram_quota(size_t amount)
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{
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if (!amount)
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return;
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_ram.withdraw_from(_child.pd_session_cap(), amount);
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_ram_quota -= amount;
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}
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/**
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* Upgrade quota of child
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*
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* \throw Ram::Transfer_quota_failed
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*/
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void upgrade_ram_quota(size_t amount)
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{
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_ram.transfer_to(_child.pd_session_cap(), amount);
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_ram_quota += amount;
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/* wake up child if resource request is in flight */
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size_t const req = requested_ram_quota();
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if (req && _child.pd().avail_ram().value >= req) {
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_child.notify_resource_avail();
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/* clear request state */
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_resource_args = Genode::Parent::Resource_args("");
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}
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}
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/**
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* Try to respond to a current resource request issued by the child
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*
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* This method evaluates the conditions, under which a resource
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* request can be answered: There must be enough room between the
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* current quota and the configured limit, and there must be enough
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* slack memory available. If both conditions are met, the quota
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* of the child gets upgraded.
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*/
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void try_response_to_resource_request()
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{
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size_t const req = requested_ram_quota();
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if (!req)
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return; /* no resource request in flight */
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/*
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* Respond to the current request if the requested quota fits
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* within the limit and if there is enough free quota available.
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*/
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if (req <= _ram.status().avail && req + _ram_quota <= _ram_limit) {
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try { upgrade_ram_quota(req); }
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catch (Ram::Transfer_quota_failed) { }
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}
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}
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/**
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* Set limit for on-demand RAM quota expansion
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*/
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void ram_limit(size_t limit)
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{
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_ram_limit = limit;
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try_response_to_resource_request();
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}
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struct Ram_status
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{
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size_t quota = 0, limit = 0, xfer = 0, used = 0, avail = 0, req = 0;
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Ram_status() { }
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Ram_status(size_t quota, size_t limit, size_t xfer, size_t used,
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size_t avail, size_t req)
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:
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quota(quota), limit(limit), xfer(xfer), used(used),
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avail(avail), req(req)
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{ }
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};
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/**
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* Return RAM quota status of the child
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*
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* XXX should be a const method, but the 'Pd_session' accessors
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* are not const
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*/
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Ram_status ram_status()
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{
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return Ram_status(_ram_quota,
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_ram_limit,
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_ram_quota - _child.pd().ram_quota().value,
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_child.pd().used_ram().value,
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_child.pd().avail_ram().value,
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requested_ram_quota());
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}
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/**
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* Return true if child exited and should be destructed
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*/
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bool exited() const { return _exited; }
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/****************************
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** Child_policy interface **
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****************************/
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Name name() const override { return _label; }
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Binary_name binary_name() const override { return _binary_name; }
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Genode::Pd_session_capability ref_pd_cap() const override { return _ref_pd_cap; }
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Genode::Pd_session &ref_pd() override { return _ref_pd; }
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void init(Genode::Pd_session &session, Genode::Pd_session_capability cap) override
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{
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session.ref_account(_ref_pd_cap);
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_ref_pd.transfer_quota(cap, _cap_quota);
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_ref_pd.transfer_quota(cap, Genode::Ram_quota{_ram_quota});
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}
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Route resolve_session_request(Genode::Service::Name const &name,
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Genode::Session_label const &label) override
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{
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return Route { .service = _matching_service(name, label),
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.label = label,
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.diag = Genode::Session::Diag() };
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}
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void yield_response()
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{
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if (_withdraw_on_yield_response) {
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enum { RESERVE = 4*1024*1024 };
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size_t amount = _child.pd().avail_ram().value < RESERVE
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? 0 : _child.pd().avail_ram().value - RESERVE;
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/* try to immediately withdraw freed-up resources */
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try { withdraw_ram_quota(amount); }
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catch (Ram::Transfer_quota_failed) { }
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}
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/* propagate yield-response signal */
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Genode::Signal_transmitter(_yield_response_sigh_cap).submit();
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}
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void resource_request(Genode::Parent::Resource_args const &args)
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{
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_resource_args = args;
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try_response_to_resource_request();
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}
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void exit(int exit_value) override
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{
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Genode::log("subsystem \"", name(), "\" exited with value ", exit_value);
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_exited = true;
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/* trigger destruction of the child */
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Genode::Signal_transmitter(_exit_sig_cap).submit();
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}
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};
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#endif /* _INCLUDE__CLI_MONITOR__CHILD_H_ */
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