130 lines
3.4 KiB
C++
130 lines
3.4 KiB
C++
/*
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* \brief Fast-bitmap allocator for NIC-session packet streams
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* \author Sebastian Sumpf
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* \date 2012-07-30
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*
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* This allocator can be used with a nic session. It is *not* required though.
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*/
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/*
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* Copyright (C) 2012 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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#ifndef _INCLUDE__NIC__PACKET_ALLOCATOR__
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#define _INCLUDE__NIC__PACKET_ALLOCATOR__
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#include <base/allocator.h>
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#include <util/string.h>
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namespace Nic {
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class Packet_allocator : public Genode::Range_allocator
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{
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private:
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Genode::Allocator *_md_alloc; /* meta-data allocator */
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unsigned _block_size; /* network packet size */
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Genode::addr_t _base; /* allocation base */
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unsigned *_free; /* free list */
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int _curr_idx; /* current index in free list */
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int _count; /* number of elements */
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public:
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enum { DEFAULT_PACKET_SIZE = 1600 };
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/**
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* Constructor
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*
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* \param md_alloc Meta-data allocator
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* \param block_size Size of network packet in stream
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*/
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Packet_allocator(Genode::Allocator *md_alloc,
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unsigned block_size = DEFAULT_PACKET_SIZE)
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: _md_alloc(md_alloc), _block_size(block_size), _base(0), _free(0),
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_curr_idx(0), _count(0)
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{}
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~Packet_allocator()
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{
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if (_free)
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_md_alloc->free(_free, sizeof(unsigned) * (_count / 32));
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}
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/*******************************
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** Range-allocator interface **
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*******************************/
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int add_range(Genode::addr_t base, Genode::size_t size)
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{
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if (_count)
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return -1;
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_base = base;
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_count = size / _block_size;
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_free = (unsigned *)_md_alloc->alloc(sizeof(unsigned) * (_count / 32));
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Genode::memset(_free, 0xff, sizeof(unsigned) * (_count / 32));
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return 0;
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}
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Alloc_return alloc_aligned(Genode::size_t size, void **out_addr, int) {
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return alloc(size, out_addr) ? Alloc_return::OK
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: Alloc_return::RANGE_CONFLICT; }
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bool alloc(Genode::size_t size, void **out_addr)
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{
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int free_cnt = _count / 32;
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for (register int i = 0; i < free_cnt; i++) {
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if (_free[_curr_idx] != 0) {
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unsigned msb = Genode::log2(_free[_curr_idx]);
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int elem_idx = (_curr_idx * 32) + msb;
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if (elem_idx < _count) {
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_free[_curr_idx] ^= (1 << msb);
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*out_addr = reinterpret_cast<void *>(_base + (_block_size * elem_idx));
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return true;
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}
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}
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_curr_idx = (_curr_idx + 1) % free_cnt;
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}
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return false;
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}
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void free(void *addr)
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{
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Genode::addr_t a = reinterpret_cast<Genode::addr_t>(addr);
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int elem_idx = (a - _base) / _block_size;
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if (elem_idx >= _count)
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return;
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_curr_idx = elem_idx / 32;
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_free[_curr_idx] |= (1 << (elem_idx % 32));
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}
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void free(void *addr, Genode::size_t) { free(addr); }
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/*********************
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** Dummy functions **
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*********************/
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Genode::size_t overhead(Genode::size_t) { return 0;}
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int remove_range(Genode::addr_t, Genode::size_t) { return 0;}
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Genode::size_t avail() { return 0; }
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bool valid_addr(Genode::addr_t) { return 0; }
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Alloc_return alloc_addr(Genode::size_t, Genode::addr_t) {
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return Alloc_return(Alloc_return::OUT_OF_METADATA); }
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};
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};
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#endif /* _INCLUDE__NIC__PACKET_ALLOCATOR__ */
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