diff options
Diffstat (limited to 'arch/arm26/mm/small_page.c')
| -rw-r--r-- | arch/arm26/mm/small_page.c | 192 |
1 files changed, 0 insertions, 192 deletions
diff --git a/arch/arm26/mm/small_page.c b/arch/arm26/mm/small_page.c deleted file mode 100644 index 30447106c25..00000000000 --- a/arch/arm26/mm/small_page.c +++ /dev/null @@ -1,192 +0,0 @@ -/* - * linux/arch/arm26/mm/small_page.c - * - * Copyright (C) 1996 Russell King - * Copyright (C) 2003 Ian Molton - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * Changelog: - * 26/01/1996 RMK Cleaned up various areas to make little more generic - * 07/02/1999 RMK Support added for 16K and 32K page sizes - * containing 8K blocks - * 23/05/2004 IM Fixed to use struct page->lru (thanks wli) - * - */ -#include <linux/signal.h> -#include <linux/sched.h> -#include <linux/kernel.h> -#include <linux/errno.h> -#include <linux/string.h> -#include <linux/types.h> -#include <linux/ptrace.h> -#include <linux/mman.h> -#include <linux/mm.h> -#include <linux/swap.h> -#include <linux/smp.h> -#include <linux/bitops.h> - -#include <asm/pgtable.h> - -#define PEDANTIC - -/* - * Requirement: - * We need to be able to allocate naturally aligned memory of finer - * granularity than the page size. This is typically used for the - * second level page tables on 32-bit ARMs. - * - * FIXME - this comment is *out of date* - * Theory: - * We "misuse" the Linux memory management system. We use alloc_page - * to allocate a page and then mark it as reserved. The Linux memory - * management system will then ignore the "offset", "next_hash" and - * "pprev_hash" entries in the mem_map for this page. - * - * We then use a bitstring in the "offset" field to mark which segments - * of the page are in use, and manipulate this as required during the - * allocation and freeing of these small pages. - * - * We also maintain a queue of pages being used for this purpose using - * the "next_hash" and "pprev_hash" entries of mem_map; - */ - -struct order { - struct list_head queue; - unsigned int mask; /* (1 << shift) - 1 */ - unsigned int shift; /* (1 << shift) size of page */ - unsigned int block_mask; /* nr_blocks - 1 */ - unsigned int all_used; /* (1 << nr_blocks) - 1 */ -}; - - -static struct order orders[] = { -#if PAGE_SIZE == 32768 - { LIST_HEAD_INIT(orders[0].queue), 2047, 11, 15, 0x0000ffff }, - { LIST_HEAD_INIT(orders[1].queue), 8191, 13, 3, 0x0000000f } -#else -#error unsupported page size (ARGH!) -#endif -}; - -#define USED_MAP(pg) ((pg)->index) -#define TEST_AND_CLEAR_USED(pg,off) (test_and_clear_bit(off, &USED_MAP(pg))) -#define SET_USED(pg,off) (set_bit(off, &USED_MAP(pg))) - -static DEFINE_SPINLOCK(small_page_lock); - -static unsigned long __get_small_page(int priority, struct order *order) -{ - unsigned long flags; - struct page *page; - int offset; - - do { - spin_lock_irqsave(&small_page_lock, flags); - - if (list_empty(&order->queue)) - goto need_new_page; - - page = list_entry(order->queue.next, struct page, lru); -again: -#ifdef PEDANTIC - BUG_ON(USED_MAP(page) & ~order->all_used); -#endif - offset = ffz(USED_MAP(page)); - SET_USED(page, offset); - if (USED_MAP(page) == order->all_used) - list_del_init(&page->lru); - spin_unlock_irqrestore(&small_page_lock, flags); - - return (unsigned long) page_address(page) + (offset << order->shift); - -need_new_page: - spin_unlock_irqrestore(&small_page_lock, flags); - page = alloc_page(priority); - spin_lock_irqsave(&small_page_lock, flags); - - if (list_empty(&order->queue)) { - if (!page) - goto no_page; - SetPageReserved(page); - USED_MAP(page) = 0; - list_add(&page->lru, &order->queue); - goto again; - } - - spin_unlock_irqrestore(&small_page_lock, flags); - __free_page(page); - } while (1); - -no_page: - spin_unlock_irqrestore(&small_page_lock, flags); - return 0; -} - -static void __free_small_page(unsigned long spage, struct order *order) -{ - unsigned long flags; - struct page *page; - - if (virt_addr_valid(spage)) { - page = virt_to_page(spage); - - /* - * The container-page must be marked Reserved - */ - if (!PageReserved(page) || spage & order->mask) - goto non_small; - -#ifdef PEDANTIC - BUG_ON(USED_MAP(page) & ~order->all_used); -#endif - - spage = spage >> order->shift; - spage &= order->block_mask; - - /* - * the following must be atomic wrt get_page - */ - spin_lock_irqsave(&small_page_lock, flags); - - if (USED_MAP(page) == order->all_used) - list_add(&page->lru, &order->queue); - - if (!TEST_AND_CLEAR_USED(page, spage)) - goto already_free; - - if (USED_MAP(page) == 0) - goto free_page; - - spin_unlock_irqrestore(&small_page_lock, flags); - } - return; - -free_page: - /* - * unlink the page from the small page queue and free it - */ - list_del_init(&page->lru); - spin_unlock_irqrestore(&small_page_lock, flags); - ClearPageReserved(page); - __free_page(page); - return; - -non_small: - printk("Trying to free non-small page from %p\n", __builtin_return_address(0)); - return; -already_free: - printk("Trying to free free small page from %p\n", __builtin_return_address(0)); -} - -unsigned long get_page_8k(int priority) -{ - return __get_small_page(priority, orders+1); -} - -void free_page_8k(unsigned long spage) -{ - __free_small_page(spage, orders+1); -} |