From b55887a95d71fcb62992d21edd19c871dd00403c Mon Sep 17 00:00:00 2001 From: Steffen Vogel Date: Mon, 30 Jun 2014 00:05:56 +0200 Subject: [PATCH] added bitmap allocator --- include/eduos/memory.h | 48 ++++++++++++++++++++ mm/memory.c | 101 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 149 insertions(+) create mode 100644 include/eduos/memory.h diff --git a/include/eduos/memory.h b/include/eduos/memory.h new file mode 100644 index 0000000..9a5766a --- /dev/null +++ b/include/eduos/memory.h @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2010, Stefan Lankes, RWTH Aachen University + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this + * software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * @author Steffen Vogel + * @file include/memory.h + * @brief Memory related functions + * + * This file contains platform independent memory functions + */ + +#ifndef __MEMORY_H__ +#define __MEMORY_H__ + +/** @brief Initialize the memory subsystem */ +int memory_init(); + +/** @brief Request physical page frames */ +size_t get_pages(size_t npages); + +/** @brief release physical page frames */ +int put_pages(size_t phyaddr, size_t npages); + +#endif diff --git a/mm/memory.c b/mm/memory.c index 9b32356..6c40471 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -27,8 +27,21 @@ #include #include +#include + +#include +#include +#include + static char stack[MAX_TASKS-1][KERNEL_STACK_SIZE]; +static char bitmap[BITMAP_SIZE]; + +static spinlock_t bitmap_lock = SPINLOCK_INIT; + +atomic_int32_t total_pages = ATOMIC_INIT(0); +atomic_int32_t total_allocated_pages = ATOMIC_INIT(0); +atomic_int32_t total_available_pages = ATOMIC_INIT(0); void* create_stack(tid_t id) { @@ -41,3 +54,91 @@ void* create_stack(tid_t id) return (void*) stack[id-1]; } + +inline static int page_marked(size_t i) +{ + size_t index = i >> 3; + size_t mod = i & 0x7; + + return (bitmap[index] & (1 << mod)); +} + +inline static void page_set_mark(size_t i) +{ + size_t index = i >> 3; + size_t mod = i & 0x7; + + bitmap[index] = bitmap[index] | (1 << mod); +} + +inline static void page_clear_mark(size_t i) +{ + size_t index = i / 8; + size_t mod = i % 8; + + bitmap[index] = bitmap[index] & ~(1 << mod); +} + +size_t get_pages(size_t npages) +{ + size_t cnt, off; + + if (BUILTIN_EXPECT(!npages, 0)) + return 0; + if (BUILTIN_EXPECT(npages > atomic_int32_read(&total_available_pages), 0)) + return 0; + + spinlock_lock(&bitmap_lock); + + off = 1; + while (off <= BITMAP_SIZE*8 - npages) { + for (cnt=0; cnt> PAGE_BITS; + + if (BUILTIN_EXPECT(!phyaddr, 0)) + return -EINVAL; + if (BUILTIN_EXPECT(!npages, 0)) + return -EINVAL; + + spinlock_lock(&bitmap_lock); + + for (i=0; i