300 lines
8.3 KiB
C++
300 lines
8.3 KiB
C++
/*
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* \brief Core implementation of the RAM session interface
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* \author Norman Feske
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* \date 2006-05-19
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*/
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/*
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* Copyright (C) 2006-2013 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 General Public License version 2.
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*/
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/* Genode includes */
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#include <base/printf.h>
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#include <util/arg_string.h>
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/* core includes */
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#include <ram_session_component.h>
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using namespace Genode;
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static const bool verbose = false;
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addr_t Ram_session_component::phys_addr(Ram_dataspace_capability ds)
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{
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Object_pool<Dataspace_component>::Guard dsc(_ds_ep->lookup_and_lock(ds));
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if (!dsc) throw Invalid_dataspace();
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return dsc->phys_addr();
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}
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void Ram_session_component::_free_ds(Dataspace_component *ds)
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{
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if (!ds) return;
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if (!ds->owner(this)) return;
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size_t ds_size = ds->size();
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/* tell entry point to forget the dataspace */
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_ds_ep->dissolve(ds);
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/* destroy native shared memory representation */
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_revoke_ram_ds(ds);
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/* XXX: remove dataspace from all RM sessions */
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/* free physical memory that was backing the dataspace */
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_ram_alloc->free((void *)ds->phys_addr(), ds_size);
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/* call dataspace destructors and free memory */
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destroy(&_ds_slab, ds);
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/* adjust payload */
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Lock::Guard lock_guard(_ref_members_lock);
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_payload -= ds_size;
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}
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int Ram_session_component::_transfer_quota(Ram_session_component *dst, size_t amount)
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{
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/* check if recipient is a valid Ram_session_component */
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if (!dst) return -1;
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/* check for reference account relationship */
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if ((ref_account() != dst) && (dst->ref_account() != this))
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return -2;
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/* decrease quota limit of this session - check against used quota */
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if (_quota_limit < amount + _payload) {
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PWRN("Insufficient quota for transfer: %s", _label);
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PWRN(" have %zd, need %zd", _quota_limit - _payload, amount);
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return -3;
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}
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_quota_limit -= amount;
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/* increase quota_limit of recipient */
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dst->_quota_limit += amount;
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return 0;
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}
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void Ram_session_component::_register_ref_account_member(Ram_session_component *new_member)
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{
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Lock::Guard lock_guard(_ref_members_lock);
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_ref_members.insert(new_member);
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new_member->_ref_account = this;
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}
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void Ram_session_component::_unsynchronized_remove_ref_account_member(Ram_session_component *member)
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{
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member->_ref_account = 0;
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_ref_members.remove(member);
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}
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void Ram_session_component::_remove_ref_account_member(Ram_session_component *member)
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{
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Lock::Guard lock_guard(_ref_members_lock);
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_unsynchronized_remove_ref_account_member(member);
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}
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Ram_dataspace_capability Ram_session_component::alloc(size_t ds_size, bool cached)
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{
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/* zero-sized dataspaces are not allowed */
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if (!ds_size) return Ram_dataspace_capability();
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/* dataspace allocation granularity is page size */
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ds_size = align_addr(ds_size, 12);
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/*
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* Check quota!
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*
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* In the worst case, we need to allocate a new slab block for the
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* meta data of the dataspace to be created - therefore, we add
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* the slab block size here.
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*/
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if (used_quota() + SBS + ds_size >= _quota_limit) {
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PWRN("Quota exceeded: %s", _label);
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PWRN(" memory for slab: %zd", _ds_slab.consumed());
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PWRN(" used quota: %zd", used_quota());
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PWRN(" ds_size: %zd", ds_size);
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PWRN(" sizeof(Ram_session_component): %zd", sizeof(Ram_session_component));
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PWRN(" quota_limit: %zd", _quota_limit);
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throw Quota_exceeded();
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}
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/*
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* Allocate physical backing store
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*
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* As an optimization for the use of large mapping sizes, we try to
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* align the dataspace in physical memory naturally (size-aligned).
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* If this does not work, we subsequently weaken the alignment constraint
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* until the allocation succeeds.
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*/
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void *ds_addr = 0;
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bool alloc_succeeded = false;
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for (size_t align_log2 = log2(ds_size); align_log2 >= 12; align_log2--) {
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if (_ram_alloc->alloc_aligned(ds_size, &ds_addr, align_log2).is_ok()) {
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alloc_succeeded = true;
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break;
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}
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}
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/*
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* Normally, init's quota equals the size of physical memory and this quota
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* is distributed among the processes. As we check the quota before
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* allocating, the allocation should always succeed in theory. However,
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* fragmentation could cause a failing allocation.
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*/
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if (!alloc_succeeded) {
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PERR("We ran out of physical memory while allocating %zd bytes", ds_size);
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throw Quota_exceeded();
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}
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Dataspace_component *ds;
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try {
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/*
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* For non-cached RAM dataspaces, we mark the dataspace as write
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* combined and expect the pager to evaluate this dataspace property
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* when resolving page faults.
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*/
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ds = new (&_ds_slab)
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Dataspace_component(ds_size, (addr_t)ds_addr, !cached, true, this);
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} catch (Allocator::Out_of_memory) {
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PWRN("Could not allocate metadata");
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throw Out_of_metadata();
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}
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/*
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* Fill new dataspaces with zeros. For non-cached RAM dataspaces, this
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* function must also make sure to flush all cache lines related to the
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* address range used by the dataspace.
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*/
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_clear_ds(ds);
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if (verbose)
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PDBG("ds_size=%zd, used_quota=%zd quota_limit=%zd",
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ds_size, used_quota(), _quota_limit);
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Dataspace_capability result = _ds_ep->manage(ds);
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/* create native shared memory representation of dataspace */
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_export_ram_ds(ds);
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Lock::Guard lock_guard(_ref_members_lock);
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/* keep track of the used quota for actual payload */
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_payload += ds_size;
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return static_cap_cast<Ram_dataspace>(result);
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}
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void Ram_session_component::free(Ram_dataspace_capability ds_cap)
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{
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Dataspace_component * ds =
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dynamic_cast<Dataspace_component *>(_ds_ep->lookup_and_lock(ds_cap));
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if (!ds)
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return;
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_free_ds(ds);
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}
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int Ram_session_component::ref_account(Ram_session_capability ram_session_cap)
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{
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/* the reference account cannot be defined twice */
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if (_ref_account) return -2;
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Object_pool<Ram_session_component>::Guard ref(_ram_session_ep->lookup_and_lock(ram_session_cap));
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/* check if recipient is a valid Ram_session_component */
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if (!ref) return -1;
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/* deny the usage of the ram session as its own ref account */
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/* XXX also check for cycles along the tree of ref accounts */
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if (ref == this) return -3;
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_ref_account = ref;
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_ref_account->_register_ref_account_member(this);
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return 0;
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}
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int Ram_session_component::transfer_quota(Ram_session_capability ram_session_cap,
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size_t amount)
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{
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if (verbose)
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PDBG("amount=%zd", amount);
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Object_pool<Ram_session_component>::Guard dst(_ram_session_ep->lookup_and_lock(ram_session_cap));
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return _transfer_quota(dst, amount);
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}
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Ram_session_component::Ram_session_component(Rpc_entrypoint *ds_ep,
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Rpc_entrypoint *ram_session_ep,
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Range_allocator *ram_alloc,
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Allocator *md_alloc,
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const char *args,
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size_t quota_limit)
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:
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_ds_ep(ds_ep), _ram_session_ep(ram_session_ep), _ram_alloc(ram_alloc),
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_quota_limit(quota_limit), _payload(0),
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_md_alloc(md_alloc, Arg_string::find_arg(args, "ram_quota").long_value(0)),
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_ds_slab(&_md_alloc), _ref_account(0)
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{
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Arg_string::find_arg(args, "label").string(_label, sizeof(_label), "");
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}
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Ram_session_component::~Ram_session_component()
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{
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/* destroy all dataspaces */
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for (Dataspace_component *ds; (ds = _ds_slab.raw()->first_object()); _free_ds(ds));
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if (_payload != 0)
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PWRN("Remaining payload of %zd in ram session to destroy", _payload);
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if (!_ref_account) return;
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/* transfer remaining quota to reference account */
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_transfer_quota(_ref_account, _quota_limit);
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/* remember our original reference account */
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Ram_session_component *orig_ref_account = _ref_account;
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/* remove reference to us from the reference account */
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_ref_account->_remove_ref_account_member(this);
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/*
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* Now, the '_ref_account' member has become invalid.
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*/
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Lock::Guard lock_guard(_ref_members_lock);
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/* assign all sub accounts to our original reference account */
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for (Ram_session_component *rsc; (rsc = _ref_members.first()); ) {
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_unsynchronized_remove_ref_account_member(rsc);
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/*
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* This function grabs the '_ref_account_lock' of the '_ref_account',
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* which is never identical to ourself. Hence, deadlock cannot happen
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* here.
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*/
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orig_ref_account->_register_ref_account_member(rsc);
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}
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_ref_account = 0;
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}
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