q3k
/
linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
linux/arch/m68k/atari/stram.c

1248 lines
34 KiB
C
Raw Blame History

This file contains invisible Unicode characters!

This file contains invisible Unicode characters that may be processed differently from what appears below. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to reveal hidden characters.

/*
* 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, &region_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:
*/
Reference in New Issue View Git Blame Copy Permalink