diff options
Diffstat (limited to 'arch/m68k/atari/stram.c')
| -rw-r--r-- | arch/m68k/atari/stram.c | 1247 |
1 files changed, 1247 insertions, 0 deletions
diff --git a/arch/m68k/atari/stram.c b/arch/m68k/atari/stram.c new file mode 100644 index 0000000..5a3c106 --- /dev/null +++ b/arch/m68k/atari/stram.c @@ -0,0 +1,1247 @@ +/* + * arch/m68k/atari/stram.c: Functions for ST-RAM allocations + * + * Copyright 1994-97 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + +#include <linux/config.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/kdev_t.h> +#include <linux/major.h> +#include <linux/init.h> +#include <linux/swap.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/pagemap.h> +#include <linux/shm.h> +#include <linux/bootmem.h> +#include <linux/mount.h> +#include <linux/blkdev.h> + +#include <asm/setup.h> +#include <asm/machdep.h> +#include <asm/page.h> +#include <asm/pgtable.h> +#include <asm/atarihw.h> +#include <asm/atari_stram.h> +#include <asm/io.h> +#include <asm/semaphore.h> + +#include <linux/swapops.h> + +#undef DEBUG + +#ifdef DEBUG +#define DPRINTK(fmt,args...) printk( fmt, ##args ) +#else +#define DPRINTK(fmt,args...) +#endif + +#if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC) +/* abbrev for the && above... */ +#define DO_PROC +#include <linux/proc_fs.h> +#endif + +/* Pre-swapping comments: + * + * ++roman: + * + * New version of ST-Ram buffer allocation. Instead of using the + * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000 + * (1 MB granularity!), such buffers are reserved like this: + * + * - If the kernel resides in ST-Ram anyway, we can take the buffer + * from behind the current kernel data space the normal way + * (incrementing start_mem). + * + * - If the kernel is in TT-Ram, stram_init() initializes start and + * end of the available region. Buffers are allocated from there + * and mem_init() later marks the such used pages as reserved. + * Since each TT-Ram chunk is at least 4 MB in size, I hope there + * won't be an overrun of the ST-Ram region by normal kernel data + * space. + * + * For that, ST-Ram may only be allocated while kernel initialization + * is going on, or exactly: before mem_init() is called. There is also + * no provision now for freeing ST-Ram buffers. It seems that isn't + * really needed. + * + */ + +/* + * New Nov 1997: Use ST-RAM as swap space! + * + * In the past, there were often problems with modules that require ST-RAM + * buffers. Such drivers have to use __get_dma_pages(), which unfortunately + * often isn't very successful in allocating more than 1 page :-( [1] The net + * result was that most of the time you couldn't insmod such modules (ataflop, + * ACSI, SCSI on Falcon, Atari internal framebuffer, not to speak of acsi_slm, + * which needs a 1 MB buffer... :-). + * + * To overcome this limitation, ST-RAM can now be turned into a very + * high-speed swap space. If a request for an ST-RAM buffer comes, the kernel + * now tries to unswap some pages on that swap device to make some free (and + * contiguous) space. This works much better in comparison to + * __get_dma_pages(), since used swap pages can be selectively freed by either + * moving them to somewhere else in swap space, or by reading them back into + * system memory. Ok, there operation of unswapping isn't really cheap (for + * each page, one has to go through the page tables of all processes), but it + * doesn't happen that often (only when allocation ST-RAM, i.e. when loading a + * module that needs ST-RAM). But it at least makes it possible to load such + * modules! + * + * It could also be that overall system performance increases a bit due to + * ST-RAM swapping, since slow ST-RAM isn't used anymore for holding data or + * executing code in. It's then just a (very fast, compared to disk) back + * storage for not-so-often needed data. (But this effect must be compared + * with the loss of total memory...) Don't know if the effect is already + * visible on a TT, where the speed difference between ST- and TT-RAM isn't + * that dramatic, but it should on machines where TT-RAM is really much faster + * (e.g. Afterburner). + * + * [1]: __get_free_pages() does a fine job if you only want one page, but if + * you want more (contiguous) pages, it can give you such a block only if + * there's already a free one. The algorithm can't try to free buffers or swap + * out something in order to make more free space, since all that page-freeing + * mechanisms work "target-less", i.e. they just free something, but not in a + * specific place. I.e., __get_free_pages() can't do anything to free + * *adjacent* pages :-( This situation becomes even worse for DMA memory, + * since the freeing algorithms are also blind to DMA capability of pages. + */ + +/* 1998-10-20: ++andreas + unswap_by_move disabled because it does not handle swapped shm pages. +*/ + +/* 2000-05-01: ++andreas + Integrated with bootmem. Remove all traces of unswap_by_move. +*/ + +#ifdef CONFIG_STRAM_SWAP +#define ALIGN_IF_SWAP(x) PAGE_ALIGN(x) +#else +#define ALIGN_IF_SWAP(x) (x) +#endif + +/* get index of swap page at address 'addr' */ +#define SWAP_NR(addr) (((addr) - swap_start) >> PAGE_SHIFT) + +/* get address of swap page #'nr' */ +#define SWAP_ADDR(nr) (swap_start + ((nr) << PAGE_SHIFT)) + +/* get number of pages for 'n' bytes (already page-aligned) */ +#define N_PAGES(n) ((n) >> PAGE_SHIFT) + +/* The following two numbers define the maximum fraction of ST-RAM in total + * memory, below that the kernel would automatically use ST-RAM as swap + * space. This decision can be overridden with stram_swap= */ +#define MAX_STRAM_FRACTION_NOM 1 +#define MAX_STRAM_FRACTION_DENOM 3 + +/* Start and end (virtual) of ST-RAM */ +static void *stram_start, *stram_end; + +/* set after memory_init() executed and allocations via start_mem aren't + * possible anymore */ +static int mem_init_done; + +/* set if kernel is in ST-RAM */ +static int kernel_in_stram; + +typedef struct stram_block { + struct stram_block *next; + void *start; + unsigned long size; + unsigned flags; + const char *owner; +} BLOCK; + +/* values for flags field */ +#define BLOCK_FREE 0x01 /* free structure in the BLOCKs pool */ +#define BLOCK_KMALLOCED 0x02 /* structure allocated by kmalloc() */ +#define BLOCK_GFP 0x08 /* block allocated with __get_dma_pages() */ +#define BLOCK_INSWAP 0x10 /* block allocated in swap space */ + +/* list of allocated blocks */ +static BLOCK *alloc_list; + +/* We can't always use kmalloc() to allocate BLOCK structures, since + * stram_alloc() can be called rather early. So we need some pool of + * statically allocated structures. 20 of them is more than enough, so in most + * cases we never should need to call kmalloc(). */ +#define N_STATIC_BLOCKS 20 +static BLOCK static_blocks[N_STATIC_BLOCKS]; + +#ifdef CONFIG_STRAM_SWAP +/* max. number of bytes to use for swapping + * 0 = no ST-RAM swapping + * -1 = do swapping (to whole ST-RAM) if it's less than MAX_STRAM_FRACTION of + * total memory + */ +static int max_swap_size = -1; + +/* start and end of swapping area */ +static void *swap_start, *swap_end; + +/* The ST-RAM's swap info structure */ +static struct swap_info_struct *stram_swap_info; + +/* The ST-RAM's swap type */ +static int stram_swap_type; + +/* Semaphore for get_stram_region. */ +static DECLARE_MUTEX(stram_swap_sem); + +/* major and minor device number of the ST-RAM device; for the major, we use + * the same as Amiga z2ram, which is really similar and impossible on Atari, + * and for the minor a relatively odd number to avoid the user creating and + * using that device. */ +#define STRAM_MAJOR Z2RAM_MAJOR +#define STRAM_MINOR 13 + +/* Some impossible pointer value */ +#define MAGIC_FILE_P (struct file *)0xffffdead + +#ifdef DO_PROC +static unsigned stat_swap_read; +static unsigned stat_swap_write; +static unsigned stat_swap_force; +#endif /* DO_PROC */ + +#endif /* CONFIG_STRAM_SWAP */ + +/***************************** Prototypes *****************************/ + +#ifdef CONFIG_STRAM_SWAP +static int swap_init(void *start_mem, void *swap_data); +static void *get_stram_region( unsigned long n_pages ); +static void free_stram_region( unsigned long offset, unsigned long n_pages + ); +static int in_some_region(void *addr); +static unsigned long find_free_region( unsigned long n_pages, unsigned long + *total_free, unsigned long + *region_free ); +static void do_stram_request(request_queue_t *); +static int stram_open( struct inode *inode, struct file *filp ); +static int stram_release( struct inode *inode, struct file *filp ); +static void reserve_region(void *start, void *end); +#endif +static BLOCK *add_region( void *addr, unsigned long size ); +static BLOCK *find_region( void *addr ); +static int remove_region( BLOCK *block ); + +/************************* End of Prototypes **************************/ + + +/* ------------------------------------------------------------------------ */ +/* Public Interface */ +/* ------------------------------------------------------------------------ */ + +/* + * This init function is called very early by atari/config.c + * It initializes some internal variables needed for stram_alloc() + */ +void __init atari_stram_init(void) +{ + int i; + + /* initialize static blocks */ + for( i = 0; i < N_STATIC_BLOCKS; ++i ) + static_blocks[i].flags = BLOCK_FREE; + + /* determine whether kernel code resides in ST-RAM (then ST-RAM is the + * first memory block at virtual 0x0) */ + stram_start = phys_to_virt(0); + kernel_in_stram = (stram_start == 0); + + for( i = 0; i < m68k_num_memory; ++i ) { + if (m68k_memory[i].addr == 0) { + /* skip first 2kB or page (supervisor-only!) */ + stram_end = stram_start + m68k_memory[i].size; + return; + } + } + /* Should never come here! (There is always ST-Ram!) */ + panic( "atari_stram_init: no ST-RAM found!" ); +} + + +/* + * This function is called from setup_arch() to reserve the pages needed for + * ST-RAM management. + */ +void __init atari_stram_reserve_pages(void *start_mem) +{ +#ifdef CONFIG_STRAM_SWAP + /* if max_swap_size is negative (i.e. no stram_swap= option given), + * determine at run time whether to use ST-RAM swapping */ + if (max_swap_size < 0) + /* Use swapping if ST-RAM doesn't make up more than MAX_STRAM_FRACTION + * of total memory. In that case, the max. size is set to 16 MB, + * because ST-RAM can never be bigger than that. + * Also, never use swapping on a Hades, there's no separate ST-RAM in + * that machine. */ + max_swap_size = + (!MACH_IS_HADES && + (N_PAGES(stram_end-stram_start)*MAX_STRAM_FRACTION_DENOM <= + ((unsigned long)high_memory>>PAGE_SHIFT)*MAX_STRAM_FRACTION_NOM)) ? 16*1024*1024 : 0; + DPRINTK( "atari_stram_reserve_pages: max_swap_size = %d\n", max_swap_size ); +#endif + + /* always reserve first page of ST-RAM, the first 2 kB are + * supervisor-only! */ + if (!kernel_in_stram) + reserve_bootmem (0, PAGE_SIZE); + +#ifdef CONFIG_STRAM_SWAP + { + void *swap_data; + + start_mem = (void *) PAGE_ALIGN ((unsigned long) start_mem); + /* determine first page to use as swap: if the kernel is + in TT-RAM, this is the first page of (usable) ST-RAM; + otherwise just use the end of kernel data (= start_mem) */ + swap_start = !kernel_in_stram ? stram_start + PAGE_SIZE : start_mem; + /* decrement by one page, rest of kernel assumes that first swap page + * is always reserved and maybe doesn't handle swp_entry == 0 + * correctly */ + swap_start -= PAGE_SIZE; + swap_end = stram_end; + if (swap_end-swap_start > max_swap_size) + swap_end = swap_start + max_swap_size; + DPRINTK( "atari_stram_reserve_pages: swapping enabled; " + "swap=%p-%p\n", swap_start, swap_end); + + /* reserve some amount of memory for maintainance of + * swapping itself: one page for each 2048 (PAGE_SIZE/2) + * swap pages. (2 bytes for each page) */ + swap_data = start_mem; + start_mem += ((SWAP_NR(swap_end) + PAGE_SIZE/2 - 1) + >> (PAGE_SHIFT-1)) << PAGE_SHIFT; + /* correct swap_start if necessary */ + if (swap_start + PAGE_SIZE == swap_data) + swap_start = start_mem - PAGE_SIZE; + + if (!swap_init( start_mem, swap_data )) { + printk( KERN_ERR "ST-RAM swap space initialization failed\n" ); + max_swap_size = 0; + return; + } + /* reserve region for swapping meta-data */ + reserve_region(swap_data, start_mem); + /* reserve swapping area itself */ + reserve_region(swap_start + PAGE_SIZE, swap_end); + + /* + * If the whole ST-RAM is used for swapping, there are no allocatable + * dma pages left. But unfortunately, some shared parts of the kernel + * (particularly the SCSI mid-level) call __get_dma_pages() + * unconditionally :-( These calls then fail, and scsi.c even doesn't + * check for NULL return values and just crashes. The quick fix for + * this (instead of doing much clean up work in the SCSI code) is to + * pretend all pages are DMA-able by setting mach_max_dma_address to + * ULONG_MAX. This doesn't change any functionality so far, since + * get_dma_pages() shouldn't be used on Atari anyway anymore (better + * use atari_stram_alloc()), and the Atari SCSI drivers don't need DMA + * memory. But unfortunately there's now no kind of warning (even not + * a NULL return value) if you use get_dma_pages() nevertheless :-( + * You just will get non-DMA-able memory... + */ + mach_max_dma_address = 0xffffffff; + } +#endif +} + +void atari_stram_mem_init_hook (void) +{ + mem_init_done = 1; +} + + +/* + * This is main public interface: somehow allocate a ST-RAM block + * There are three strategies: + * + * - If we're before mem_init(), we have to make a static allocation. The + * region is taken in the kernel data area (if the kernel is in ST-RAM) or + * from the start of ST-RAM (if the kernel is in TT-RAM) and added to the + * rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel + * address space in the latter case. + * + * - If mem_init() already has been called and ST-RAM swapping is enabled, + * try to get the memory from the (pseudo) swap-space, either free already + * or by moving some other pages out of the swap. + * + * - If mem_init() already has been called, and ST-RAM swapping is not + * enabled, the only possibility is to try with __get_dma_pages(). This has + * the disadvantage that it's very hard to get more than 1 page, and it is + * likely to fail :-( + * + */ +void *atari_stram_alloc(long size, const char *owner) +{ + void *addr = NULL; + BLOCK *block; + int flags; + + DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner); + + size = ALIGN_IF_SWAP(size); + DPRINTK( "atari_stram_alloc: rounded size = %08lx\n", size ); +#ifdef CONFIG_STRAM_SWAP + if (max_swap_size) { + /* If swapping is active: make some free space in the swap + "device". */ + DPRINTK( "atari_stram_alloc: after mem_init, swapping ok, " + "calling get_region\n" ); + addr = get_stram_region( N_PAGES(size) ); + flags = BLOCK_INSWAP; + } + else +#endif + if (!mem_init_done) + return alloc_bootmem_low(size); + else { + /* After mem_init() and no swapping: can only resort to + * __get_dma_pages() */ + addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size)); + flags = BLOCK_GFP; + DPRINTK( "atari_stram_alloc: after mem_init, swapping off, " + "get_pages=%p\n", addr ); + } + + if (addr) { + if (!(block = add_region( addr, size ))) { + /* out of memory for BLOCK structure :-( */ + DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- " + "freeing again\n" ); +#ifdef CONFIG_STRAM_SWAP + if (flags == BLOCK_INSWAP) + free_stram_region( SWAP_NR(addr), N_PAGES(size) ); + else +#endif + free_pages((unsigned long)addr, get_order(size)); + return( NULL ); + } + block->owner = owner; + block->flags |= flags; + } + return( addr ); +} + +void atari_stram_free( void *addr ) + +{ + BLOCK *block; + + DPRINTK( "atari_stram_free(addr=%p)\n", addr ); + + if (!(block = find_region( addr ))) { + printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p " + "from %p\n", addr, __builtin_return_address(0) ); + return; + } + DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, " + "flags=%02x\n", block, block->size, block->owner, block->flags ); + +#ifdef CONFIG_STRAM_SWAP + if (!max_swap_size) { +#endif + if (block->flags & BLOCK_GFP) { + DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n", + get_order(block->size)); + free_pages((unsigned long)addr, get_order(block->size)); + } + else + goto fail; +#ifdef CONFIG_STRAM_SWAP + } + else if (block->flags & BLOCK_INSWAP) { + DPRINTK( "atari_stram_free: is swap-alloced\n" ); + free_stram_region( SWAP_NR(block->start), N_PAGES(block->size) ); + } + else + goto fail; +#endif + remove_region( block ); + return; + + fail: + printk( KERN_ERR "atari_stram_free: cannot free block at %p " + "(called from %p)\n", addr, __builtin_return_address(0) ); +} + + +#ifdef CONFIG_STRAM_SWAP + + +/* ------------------------------------------------------------------------ */ +/* Main Swapping Functions */ +/* ------------------------------------------------------------------------ */ + + +/* + * Initialize ST-RAM swap device + * (lots copied and modified from sys_swapon() in mm/swapfile.c) + */ +static int __init swap_init(void *start_mem, void *swap_data) +{ + static struct dentry fake_dentry; + static struct vfsmount fake_vfsmnt; + struct swap_info_struct *p; + struct inode swap_inode; + unsigned int type; + void *addr; + int i, j, k, prev; + + DPRINTK("swap_init(start_mem=%p, swap_data=%p)\n", + start_mem, swap_data); + + /* need at least one page for swapping to (and this also isn't very + * much... :-) */ + if (swap_end - swap_start < 2*PAGE_SIZE) { + printk( KERN_WARNING "stram_swap_init: swap space too small\n" ); + return( 0 ); + } + + /* find free slot in swap_info */ + for( p = swap_info, type = 0; type < nr_swapfiles; type++, p++ ) + if (!(p->flags & SWP_USED)) + break; + if (type >= MAX_SWAPFILES) { + printk( KERN_WARNING "stram_swap_init: max. number of " + "swap devices exhausted\n" ); + return( 0 ); + } + if (type >= nr_swapfiles) + nr_swapfiles = type+1; + + stram_swap_info = p; + stram_swap_type = type; + + /* fake some dir cache entries to give us some name in /dev/swaps */ + fake_dentry.d_parent = &fake_dentry; + fake_dentry.d_name.name = "stram (internal)"; + fake_dentry.d_name.len = 16; + fake_vfsmnt.mnt_parent = &fake_vfsmnt; + + p->flags = SWP_USED; + p->swap_file = &fake_dentry; + p->swap_vfsmnt = &fake_vfsmnt; + p->swap_map = swap_data; + p->cluster_nr = 0; + p->next = -1; + p->prio = 0x7ff0; /* a rather high priority, but not the higest + * to give the user a chance to override */ + + /* call stram_open() directly, avoids at least the overhead in + * constructing a dummy file structure... */ + swap_inode.i_rdev = MKDEV( STRAM_MAJOR, STRAM_MINOR ); + stram_open( &swap_inode, MAGIC_FILE_P ); + p->max = SWAP_NR(swap_end); + + /* initialize swap_map: set regions that are already allocated or belong + * to kernel data space to SWAP_MAP_BAD, otherwise to free */ + j = 0; /* # of free pages */ + k = 0; /* # of already allocated pages (from pre-mem_init stram_alloc()) */ + p->lowest_bit = 0; + p->highest_bit = 0; + for( i = 1, addr = SWAP_ADDR(1); i < p->max; + i++, addr += PAGE_SIZE ) { + if (in_some_region( addr )) { + p->swap_map[i] = SWAP_MAP_BAD; + ++k; + } + else if (kernel_in_stram && addr < start_mem ) { + p->swap_map[i] = SWAP_MAP_BAD; + } + else { + p->swap_map[i] = 0; + ++j; + if (!p->lowest_bit) p->lowest_bit = i; + p->highest_bit = i; + } + } + /* first page always reserved (and doesn't really belong to swap space) */ + p->swap_map[0] = SWAP_MAP_BAD; + + /* now swapping to this device ok */ + p->pages = j + k; + swap_list_lock(); + nr_swap_pages += j; + p->flags = SWP_WRITEOK; + + /* insert swap space into swap_list */ + prev = -1; + for (i = swap_list.head; i >= 0; i = swap_info[i].next) { + if (p->prio >= swap_info[i].prio) { + break; + } + prev = i; + } + p->next = i; + if (prev < 0) { + swap_list.head = swap_list.next = p - swap_info; + } else { + swap_info[prev].next = p - swap_info; + } + swap_list_unlock(); + + printk( KERN_INFO "Using %dk (%d pages) of ST-RAM as swap space.\n", + p->pages << 2, p->pages ); + return( 1 ); +} + + +/* + * The swap entry has been read in advance, and we return 1 to indicate + * that the page has been used or is no longer needed. + * + * Always set the resulting pte to be nowrite (the same as COW pages + * after one process has exited). We don't know just how many PTEs will + * share this swap entry, so be cautious and let do_wp_page work out + * what to do if a write is requested later. + */ +static inline void unswap_pte(struct vm_area_struct * vma, unsigned long + address, pte_t *dir, swp_entry_t entry, + struct page *page) +{ + pte_t pte = *dir; + + if (pte_none(pte)) + return; + if (pte_present(pte)) { + /* If this entry is swap-cached, then page must already + hold the right address for any copies in physical + memory */ + if (pte_page(pte) != page) + return; + /* We will be removing the swap cache in a moment, so... */ + set_pte(dir, pte_mkdirty(pte)); + return; + } + if (pte_val(pte) != entry.val) + return; + + DPRINTK("unswap_pte: replacing entry %08lx by new page %p", + entry.val, page); + set_pte(dir, pte_mkdirty(mk_pte(page, vma->vm_page_prot))); + swap_free(entry); + get_page(page); + inc_mm_counter(vma->vm_mm, rss); +} + +static inline void unswap_pmd(struct vm_area_struct * vma, pmd_t *dir, + unsigned long address, unsigned long size, + unsigned long offset, swp_entry_t entry, + struct page *page) +{ + pte_t * pte; + unsigned long end; + + if (pmd_none(*dir)) + return; + if (pmd_bad(*dir)) { + pmd_ERROR(*dir); + pmd_clear(dir); + return; + } + pte = pte_offset_kernel(dir, address); + offset += address & PMD_MASK; + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + do { + unswap_pte(vma, offset+address-vma->vm_start, pte, entry, page); + address += PAGE_SIZE; + pte++; + } while (address < end); +} + +static inline void unswap_pgd(struct vm_area_struct * vma, pgd_t *dir, + unsigned long address, unsigned long size, + swp_entry_t entry, struct page *page) +{ + pmd_t * pmd; + unsigned long offset, end; + + if (pgd_none(*dir)) + return; + if (pgd_bad(*dir)) { + pgd_ERROR(*dir); + pgd_clear(dir); + return; + } + pmd = pmd_offset(dir, address); + offset = address & PGDIR_MASK; + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + do { + unswap_pmd(vma, pmd, address, end - address, offset, entry, + page); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address < end); +} + +static void unswap_vma(struct vm_area_struct * vma, pgd_t *pgdir, + swp_entry_t entry, struct page *page) +{ + unsigned long start = vma->vm_start, end = vma->vm_end; + + do { + unswap_pgd(vma, pgdir, start, end - start, entry, page); + start = (start + PGDIR_SIZE) & PGDIR_MASK; + pgdir++; + } while (start < end); +} + +static void unswap_process(struct mm_struct * mm, swp_entry_t entry, + struct page *page) +{ + struct vm_area_struct* vma; + + /* + * Go through process' page directory. + */ + if (!mm) + return; + for (vma = mm->mmap; vma; vma = vma->vm_next) { + pgd_t * pgd = pgd_offset(mm, vma->vm_start); + unswap_vma(vma, pgd, entry, page); + } +} + + +static int unswap_by_read(unsigned short *map, unsigned long max, + unsigned long start, unsigned long n_pages) +{ + struct task_struct *p; + struct page *page; + swp_entry_t entry; + unsigned long i; + + DPRINTK( "unswapping %lu..%lu by reading in\n", + start, start+n_pages-1 ); + + for( i = start; i < start+n_pages; ++i ) { + if (map[i] == SWAP_MAP_BAD) { + printk( KERN_ERR "get_stram_region: page %lu already " + "reserved??\n", i ); + continue; + } + + if (map[i]) { + entry = swp_entry(stram_swap_type, i); + DPRINTK("unswap: map[i=%lu]=%u nr_swap=%ld\n", + i, map[i], nr_swap_pages); + + swap_device_lock(stram_swap_info); + map[i]++; + swap_device_unlock(stram_swap_info); + /* Get a page for the entry, using the existing + swap cache page if there is one. Otherwise, + get a clean page and read the swap into it. */ + page = read_swap_cache_async(entry, NULL, 0); + if (!page) { + swap_free(entry); + return -ENOMEM; + } + read_lock(&tasklist_lock); + for_each_process(p) + unswap_process(p->mm, entry, page); + read_unlock(&tasklist_lock); + shmem_unuse(entry, page); + /* Now get rid of the extra reference to the + temporary page we've been using. */ + if (PageSwapCache(page)) + delete_from_swap_cache(page); + __free_page(page); + #ifdef DO_PROC + stat_swap_force++; + #endif + } + + DPRINTK( "unswap: map[i=%lu]=%u nr_swap=%ld\n", + i, map[i], nr_swap_pages ); + swap_list_lock(); + swap_device_lock(stram_swap_info); + map[i] = SWAP_MAP_BAD; + if (stram_swap_info->lowest_bit == i) + stram_swap_info->lowest_bit++; + if (stram_swap_info->highest_bit == i) + stram_swap_info->highest_bit--; + --nr_swap_pages; + swap_device_unlock(stram_swap_info); + swap_list_unlock(); + } + + return 0; +} + +/* + * reserve a region in ST-RAM swap space for an allocation + */ +static void *get_stram_region( unsigned long n_pages ) +{ + unsigned short *map = stram_swap_info->swap_map; + unsigned long max = stram_swap_info->max; + unsigned long start, total_free, region_free; + int err; + void *ret = NULL; + + DPRINTK( "get_stram_region(n_pages=%lu)\n", n_pages ); + + down(&stram_swap_sem); + + /* disallow writing to the swap device now */ + stram_swap_info->flags = SWP_USED; + + /* find a region of n_pages pages in the swap space including as much free + * pages as possible (and excluding any already-reserved pages). */ + if (!(start = find_free_region( n_pages, &total_free, ®ion_free ))) + goto end; + DPRINTK( "get_stram_region: region starts at %lu, has %lu free pages\n", + start, region_free ); + + err = unswap_by_read(map, max, start, n_pages); + if (err) + goto end; + + ret = SWAP_ADDR(start); + end: + /* allow using swap device again */ + stram_swap_info->flags = SWP_WRITEOK; + up(&stram_swap_sem); + DPRINTK( "get_stram_region: returning %p\n", ret ); + return( ret ); +} + + +/* + * free a reserved region in ST-RAM swap space + */ +static void free_stram_region( unsigned long offset, unsigned long n_pages ) +{ + unsigned short *map = stram_swap_info->swap_map; + + DPRINTK( "free_stram_region(offset=%lu,n_pages=%lu)\n", offset, n_pages ); + + if (offset < 1 || offset + n_pages > stram_swap_info->max) { + printk( KERN_ERR "free_stram_region: Trying to free non-ST-RAM\n" ); + return; + } + + swap_list_lock(); + swap_device_lock(stram_swap_info); + /* un-reserve the freed pages */ + for( ; n_pages > 0; ++offset, --n_pages ) { + if (map[offset] != SWAP_MAP_BAD) + printk( KERN_ERR "free_stram_region: Swap page %lu was not " + "reserved\n", offset ); + map[offset] = 0; + } + + /* update swapping meta-data */ + if (offset < stram_swap_info->lowest_bit) + stram_swap_info->lowest_bit = offset; + if (offset+n_pages-1 > stram_swap_info->highest_bit) + stram_swap_info->highest_bit = offset+n_pages-1; + if (stram_swap_info->prio > swap_info[swap_list.next].prio) + swap_list.next = swap_list.head; + nr_swap_pages += n_pages; + swap_device_unlock(stram_swap_info); + swap_list_unlock(); +} + + +/* ------------------------------------------------------------------------ */ +/* Utility Functions for Swapping */ +/* ------------------------------------------------------------------------ */ + + +/* is addr in some of the allocated regions? */ +static int in_some_region(void *addr) +{ + BLOCK *p; + + for( p = alloc_list; p; p = p->next ) { + if (p->start <= addr && addr < p->start + p->size) + return( 1 ); + } + return( 0 ); +} + + +static unsigned long find_free_region(unsigned long n_pages, + unsigned long *total_free, + unsigned long *region_free) +{ + unsigned short *map = stram_swap_info->swap_map; + unsigned long max = stram_swap_info->max; + unsigned long head, tail, max_start; + long nfree, max_free; + + /* first scan the swap space for a suitable place for the allocation */ + head = 1; + max_start = 0; + max_free = -1; + *total_free = 0; + + start_over: + /* increment tail until final window size reached, and count free pages */ + nfree = 0; + for( tail = head; tail-head < n_pages && tail < max; ++tail ) { + if (map[tail] == SWAP_MAP_BAD) { + head = tail+1; + goto start_over; + } + if (!map[tail]) { + ++nfree; + ++*total_free; + } + } + if (tail-head < n_pages) + goto out; + if (nfree > max_free) { + max_start = head; + max_free = nfree; + if (max_free >= n_pages) + /* don't need more free pages... :-) */ + goto out; + } + + /* now shift the window and look for the area where as much pages as + * possible are free */ + while( tail < max ) { + nfree -= (map[head++] == 0); + if (map[tail] == SWAP_MAP_BAD) { + head = tail+1; + goto start_over; + } + if (!map[tail]) { + ++nfree; + ++*total_free; + } + ++tail; + if (nfree > max_free) { + max_start = head; + max_free = nfree; + if (max_free >= n_pages) + /* don't need more free pages... :-) */ + goto out; + } + } + + out: + if (max_free < 0) { + printk( KERN_NOTICE "get_stram_region: ST-RAM too full or fragmented " + "-- can't allocate %lu pages\n", n_pages ); + return( 0 ); + } + + *region_free = max_free; + return( max_start ); +} + + +/* setup parameters from command line */ +void __init stram_swap_setup(char *str, int *ints) +{ + if (ints[0] >= 1) + max_swap_size = ((ints[1] < 0 ? 0 : ints[1]) * 1024) & PAGE_MASK; +} + + +/* ------------------------------------------------------------------------ */ +/* ST-RAM device */ +/* ------------------------------------------------------------------------ */ + +static int refcnt; + +static void do_stram_request(request_queue_t *q) +{ + struct request *req; + + while ((req = elv_next_request(q)) != NULL) { + void *start = swap_start + (req->sector << 9); + unsigned long len = req->current_nr_sectors << 9; + if ((start + len) > swap_end) { + printk( KERN_ERR "stram: bad access beyond end of device: " + "block=%ld, count=%d\n", + req->sector, + req->current_nr_sectors ); + end_request(req, 0); + continue; + } + + if (req->cmd == READ) { + memcpy(req->buffer, start, len); +#ifdef DO_PROC + stat_swap_read += N_PAGES(len); +#endif + } + else { + memcpy(start, req->buffer, len); +#ifdef DO_PROC + stat_swap_write += N_PAGES(len); +#endif + } + end_request(req, 1); + } +} + + +static int stram_open( struct inode *inode, struct file *filp ) +{ + if (filp != MAGIC_FILE_P) { + printk( KERN_NOTICE "Only kernel can open ST-RAM device\n" ); + return( -EPERM ); + } + if (refcnt) + return( -EBUSY ); + ++refcnt; + return( 0 ); +} + +static int stram_release( struct inode *inode, struct file *filp ) +{ + if (filp != MAGIC_FILE_P) { + printk( KERN_NOTICE "Only kernel can close ST-RAM device\n" ); + return( -EPERM ); + } + if (refcnt > 0) + --refcnt; + return( 0 ); +} + + +static struct block_device_operations stram_fops = { + .open = stram_open, + .release = stram_release, +}; + +static struct gendisk *stram_disk; +static struct request_queue *stram_queue; +static DEFINE_SPINLOCK(stram_lock); + +int __init stram_device_init(void) +{ + if (!MACH_IS_ATARI) + /* no point in initializing this, I hope */ + return -ENXIO; + + if (!max_swap_size) + /* swapping not enabled */ + return -ENXIO; + stram_disk = alloc_disk(1); + if (!stram_disk) + return -ENOMEM; + + if (register_blkdev(STRAM_MAJOR, "stram")) { + put_disk(stram_disk); + return -ENXIO; + } + + stram_queue = blk_init_queue(do_stram_request, &stram_lock); + if (!stram_queue) { + unregister_blkdev(STRAM_MAJOR, "stram"); + put_disk(stram_disk); + return -ENOMEM; + } + + stram_disk->major = STRAM_MAJOR; + stram_disk->first_minor = STRAM_MINOR; + stram_disk->fops = &stram_fops; + stram_disk->queue = stram_queue; + sprintf(stram_disk->disk_name, "stram"); + set_capacity(stram_disk, (swap_end - swap_start)/512); + add_disk(stram_disk); + return 0; +} + + + +/* ------------------------------------------------------------------------ */ +/* Misc Utility Functions */ +/* ------------------------------------------------------------------------ */ + +/* reserve a range of pages */ +static void reserve_region(void *start, void *end) +{ + reserve_bootmem (virt_to_phys(start), end - start); +} + +#endif /* CONFIG_STRAM_SWAP */ + + +/* ------------------------------------------------------------------------ */ +/* Region Management */ +/* ------------------------------------------------------------------------ */ + + +/* insert a region into the alloced list (sorted) */ +static BLOCK *add_region( void *addr, unsigned long size ) +{ + BLOCK **p, *n = NULL; + int i; + + for( i = 0; i < N_STATIC_BLOCKS; ++i ) { + if (static_blocks[i].flags & BLOCK_FREE) { + n = &static_blocks[i]; + n->flags = 0; + break; + } + } + if (!n && mem_init_done) { + /* if statics block pool exhausted and we can call kmalloc() already + * (after mem_init()), try that */ + n = kmalloc( sizeof(BLOCK), GFP_KERNEL ); + if (n) + n->flags = BLOCK_KMALLOCED; + } + if (!n) { + printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" ); + return( NULL ); + } + n->start = addr; + n->size = size; + + for( p = &alloc_list; *p; p = &((*p)->next) ) + if ((*p)->start > addr) break; + n->next = *p; + *p = n; + + return( n ); +} + + +/* find a region (by start addr) in the alloced list */ +static BLOCK *find_region( void *addr ) +{ + BLOCK *p; + + for( p = alloc_list; p; p = p->next ) { + if (p->start == addr) + return( p ); + if (p->start > addr) + break; + } + return( NULL ); +} + + +/* remove a block from the alloced list */ +static int remove_region( BLOCK *block ) +{ + BLOCK **p; + + for( p = &alloc_list; *p; p = &((*p)->next) ) + if (*p == block) break; + if (!*p) + return( 0 ); + + *p = block->next; + if (block->flags & BLOCK_KMALLOCED) + kfree( block ); + else + block->flags |= BLOCK_FREE; + return( 1 ); +} + + + +/* ------------------------------------------------------------------------ */ +/* /proc statistics file stuff */ +/* ------------------------------------------------------------------------ */ + +#ifdef DO_PROC + +#define PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args ) + +int get_stram_list( char *buf ) +{ + int len = 0; + BLOCK *p; +#ifdef CONFIG_STRAM_SWAP + int i; + unsigned short *map = stram_swap_info->swap_map; + unsigned long max = stram_swap_info->max; + unsigned free = 0, used = 0, rsvd = 0; +#endif + +#ifdef CONFIG_STRAM_SWAP + if (max_swap_size) { + for( i = 1; i < max; ++i ) { + if (!map[i]) + ++free; + else if (map[i] == SWAP_MAP_BAD) + ++rsvd; + else + ++used; + } + PRINT_PROC( + "Total ST-RAM: %8u kB\n" + "Total ST-RAM swap: %8lu kB\n" + "Free swap: %8u kB\n" + "Used swap: %8u kB\n" + "Allocated swap: %8u kB\n" + "Swap Reads: %8u\n" + "Swap Writes: %8u\n" + "Swap Forced Reads: %8u\n", + (stram_end - stram_start) >> 10, + (max-1) << (PAGE_SHIFT-10), + free << (PAGE_SHIFT-10), + used << (PAGE_SHIFT-10), + rsvd << (PAGE_SHIFT-10), + stat_swap_read, + stat_swap_write, + stat_swap_force ); + } + else { +#endif + PRINT_PROC( "ST-RAM swapping disabled\n" ); + PRINT_PROC("Total ST-RAM: %8u kB\n", + (stram_end - stram_start) >> 10); +#ifdef CONFIG_STRAM_SWAP + } +#endif + + PRINT_PROC( "Allocated regions:\n" ); + for( p = alloc_list; p; p = p->next ) { + if (len + 50 >= PAGE_SIZE) + break; + PRINT_PROC("0x%08lx-0x%08lx: %s (", + virt_to_phys(p->start), + virt_to_phys(p->start+p->size-1), + p->owner); + if (p->flags & BLOCK_GFP) + PRINT_PROC( "page-alloced)\n" ); + else if (p->flags & BLOCK_INSWAP) + PRINT_PROC( "in swap)\n" ); + else + PRINT_PROC( "??)\n" ); + } + + return( len ); +} + +#endif + + +/* + * Local variables: + * c-indent-level: 4 + * tab-width: 4 + * End: + */ |
