swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: 63953523341bcafe5928bf6e99bffd7db94b471e authored by Linus Torvalds on 28 July 2005, 22:44:44 UTC
Linux 2.6.13-rc4
Linux 2.6.13-rc4
Tip revision: 6395352
stram.c
/*
* 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:
*/
