/*synarthsh opoy elegxoyme ean se mia page yparxei kapoio block poy na xoraei to request mas*/
int check_block(struct slob_page *sp, size_t size, int align){
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);
slobidx_t avail ;
/*diatrexoyme thn lista mexri na broyme kapoio block opoy xoraei to request*/
for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
avail = slob_units(cur);
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
if (avail >= units + delta) { /* room enough? */
return(1);
}
/*an einai to teleytaio sth lista bgainei apo thn for */
if(slob_last(cur)){
break;
}
}
return(0);
}
/*
* Allocate a slob block within a given slob_page sp.
*/
static void *slob_page_alloc(struct page *sp, size_t size, int align)
{
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);
for (prev = NULL, cur = sp->freelist; ; prev = cur, cur = slob_next(cur)) {
slobidx_t avail = slob_units(cur);
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
if (avail >= units + delta) { /* room enough? */
slob_t *next;
if (delta) { /* need to fragment head to align? */
next = slob_next(cur);
set_slob(aligned, avail - delta, next);
set_slob(cur, delta, aligned);
prev = cur;
cur = aligned;
avail = slob_units(cur);
}
next = slob_next(cur);
if (avail == units) { /* exact fit? unlink. */
if (prev)
set_slob(prev, slob_units(prev), next);
else
sp->freelist = next;
} else { /* fragment */
if (prev)
set_slob(prev, slob_units(prev), cur + units);
else
sp->freelist = cur + units;
set_slob(cur + units, avail - units, next);
}
sp->units -= units;
if (!sp->units)
clear_slob_page_free(sp);
return cur;
}
if (slob_last(cur))
return NULL;
}
}
/*
* Allocate a slob block within a given slob_page sp.
*/
static void *slob_page_alloc(struct slob_page *sp, size_t size, int align)
{
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);
#ifdef BESTFIT_BLOCK
slob_t *min_cur = NULL,*min_aligned = NULL,*min_prev;
slobidx_t min_avail = 0;
int flag_if = 0 ,min_delta = 0;
slobidx_t avail ;
#endif
#ifdef BESTFIT_BLOCK
if((counter_print%print_iteration) == 0){
printk("\nslob_Request: %d\n",units);
printk("slob_alloc: Candidate blocks size:");
}
/*diatrexoyme thn lista mexri na broyme to best block*/
for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
avail = slob_units(cur);
if((counter_print%print_iteration) == 0){
printk(" %d",avail);
}
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
if (avail >= units + delta) { /* room enough? */
/*arxikopoioyme ta min*/
if(!flag_if){
min_avail = slob_units(cur);
min_cur = cur;
min_aligned = aligned;
min_delta = delta;
min_prev = prev;
flag_if = 1;
}
else {
/*se periptosh poy brethei kalytero block tote allazoyme tis thmes twn min*/
if(min_avail > avail){
min_avail = avail;
min_cur = cur;
min_aligned = aligned;
min_delta = delta;
min_prev = prev;
}
}
}
/*an einai to teleytaio sth lista bgainei apo thn for */
if(slob_last(cur)){
break;
}
}
/*an exei brethei block poy na xoraei to request tote to epilegoume*/
if(min_avail!=0){
slob_t *next;
cur = min_cur;
avail = min_avail;
delta = min_delta;
aligned = min_aligned;
prev = min_prev;
if (delta) { /* need to fragment head to align? */
next = slob_next(cur);
set_slob(aligned, avail - delta, next);
set_slob(cur, delta, aligned);
prev = cur;
cur = aligned;
avail = slob_units(cur);
}
next = slob_next(cur);
if (avail == units) { /* exact fit? unlink. */
if (prev)
set_slob(prev, slob_units(prev), next);
else
sp->free = next;
}
else { /* fragment */
if (prev)
set_slob(prev, slob_units(prev), cur + units);
else
sp->free = cur + units;
set_slob(cur + units, avail - units, next);
}
sp->units -= units;
if (!sp->units)
clear_slob_page_free(sp);
if((counter_print%print_iteration) == 0){
printk("\nslob_alloc: Best Fit: %d\n",min_avail);
}
return cur;
}
else{
if((counter_print%print_iteration) == 0){
printk("\nslob_alloc: Best Fit: None\n");
}
return NULL;
}
#else
if((counter_print%print_iteration) == 0){
printk("\nslob_Request: %d\n",units);
printk("slob_alloc: Candidate blocks size:");
}
for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
slobidx_t avail = slob_units(cur);
if((counter_print%print_iteration) == 0){
printk(" %d",avail);
}
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
if (avail >= units + delta) { /* room enough? */
slob_t *next;
if (delta) { /* need to fragment head to align? */
next = slob_next(cur);
set_slob(aligned, avail - delta, next);
set_slob(cur, delta, aligned);
prev = cur;
cur = aligned;
avail = slob_units(cur);
}
next = slob_next(cur);
if (avail == units) { /* exact fit? unlink. */
if (prev)
set_slob(prev, slob_units(prev), next);
else
sp->free = next;
}
else { /* fragment */
if (prev)
set_slob(prev, slob_units(prev), cur + units);
else
sp->free = cur + units;
set_slob(cur + units, avail - units, next);
}
sp->units -= units;
if (!sp->units)
clear_slob_page_free(sp);
if((counter_print%print_iteration) == 0){
printk("\nslob_alloc: First Fit is the last available\n");
}
return cur;
}
if (slob_last(cur)){
if((counter_print%print_iteration) == 0){
printk("\nslob_alloc: First Fit: None\n");
}
return NULL;
}
}
#endif
}
/*
* Returns true if s is the last free block in its page.
*/
static int slob_last(slob_t *s)
{
return !((unsigned long)slob_next(s) & ~PAGE_MASK);
}
/*
* slob_free: entry point into the slob allocator.
*/
static void slob_free(void *block, int size)
{
struct page *sp;
slob_t *prev, *next, *b = (slob_t *)block;
slobidx_t units;
unsigned long flags;
struct list_head *slob_list;
if (unlikely(ZERO_OR_NULL_PTR(block)))
return;
BUG_ON(!size);
sp = virt_to_page(block);
units = SLOB_UNITS(size);
spin_lock_irqsave(&slob_lock, flags);
if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
/* Go directly to page allocator. Do not pass slob allocator */
if (slob_page_free(sp))
clear_slob_page_free(sp);
spin_unlock_irqrestore(&slob_lock, flags);
__ClearPageSlab(sp);
page_mapcount_reset(sp);
slob_free_pages(b, 0);
return;
}
if (!slob_page_free(sp)) {
/* This slob page is about to become partially free. Easy! */
sp->units = units;
sp->freelist = b;
set_slob(b, units,
(void *)((unsigned long)(b +
SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
if (size < SLOB_BREAK1)
slob_list = &free_slob_small;
else if (size < SLOB_BREAK2)
slob_list = &free_slob_medium;
else
slob_list = &free_slob_large;
set_slob_page_free(sp, slob_list);
goto out;
}
/*
* Otherwise the page is already partially free, so find reinsertion
* point.
*/
sp->units += units;
if (b < (slob_t *)sp->freelist) {
if (b + units == sp->freelist) {
units += slob_units(sp->freelist);
sp->freelist = slob_next(sp->freelist);
}
set_slob(b, units, sp->freelist);
sp->freelist = b;
} else {
prev = sp->freelist;
next = slob_next(prev);
while (b > next) {
prev = next;
next = slob_next(prev);
}
if (!slob_last(prev) && b + units == next) {
units += slob_units(next);
set_slob(b, units, slob_next(next));
} else
set_slob(b, units, next);
if (prev + slob_units(prev) == b) {
units = slob_units(b) + slob_units(prev);
set_slob(prev, units, slob_next(b));
} else
set_slob(prev, slob_units(prev), b);
}
out:
spin_unlock_irqrestore(&slob_lock, flags);
}
static void slob_free(void *block, int size)
{
struct page *sp;
slob_t *prev, *next, *b = (slob_t *)block;
slobidx_t units;
unsigned long flags;
struct list_head *slob_list;
if (unlikely(ZERO_OR_NULL_PTR(block)))
return;
BUG_ON(!size);
sp = slob_page(block);
units = SLOB_UNITS(size);
spin_lock_irqsave(&slob_lock, flags);
if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
if (slob_page_free(sp))
clear_slob_page_free(sp);
spin_unlock_irqrestore(&slob_lock, flags);
clear_slob_page(sp);
free_slob_page(sp);
slob_free_pages(b, 0);
return;
}
if (!slob_page_free(sp)) {
sp->units = units;
sp->freelist = b;
set_slob(b, units,
(void *)((unsigned long)(b +
SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
if (size < SLOB_BREAK1)
slob_list = &free_slob_small;
else if (size < SLOB_BREAK2)
slob_list = &free_slob_medium;
else
slob_list = &free_slob_large;
set_slob_page_free(sp, slob_list);
goto out;
}
sp->units += units;
if (b < (slob_t *)sp->freelist) {
if (b + units == sp->freelist) {
units += slob_units(sp->freelist);
sp->freelist = slob_next(sp->freelist);
}
set_slob(b, units, sp->freelist);
sp->freelist = b;
} else {
prev = sp->freelist;
next = slob_next(prev);
while (b > next) {
prev = next;
next = slob_next(prev);
}
if (!slob_last(prev) && b + units == next) {
units += slob_units(next);
set_slob(b, units, slob_next(next));
} else
set_slob(b, units, next);
if (prev + slob_units(prev) == b) {
units = slob_units(b) + slob_units(prev);
set_slob(prev, units, slob_next(b));
} else
set_slob(prev, slob_units(prev), b);
}
out:
spin_unlock_irqrestore(&slob_lock, flags);
}
/*
* Allocate a slob block within a given slob_page sp.
*
* We modified the slob_page_alloc function to find the
* best block on a given page. We understand that it is
* searching through a page's free blocks twice (once
* from the helper, and a second time for this function).
* We make a best version of all the variables in the
* function to keep track of the best block. Then we go
* through the entire block list and return the best block.
*/
static void *slob_page_alloc(struct slob_page *sp, size_t size, int align)
{
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);
slob_t *best_prev = NULL, *best_cur = NULL, *best_aligned = NULL;
int best_delta = 0;
slobidx_t best_fit = 0;
for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
slobidx_t avail = slob_units(cur);
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
#ifdef SLOB_BEST_FIT_ALG
if (avail >= units + delta && (best_cur == NULL || avail - (units + delta) < best_fit) ) { /* room enough? */
#else
if (avail >= units + delta) { /* room enough? */
#endif
best_prev = prev;
best_cur = cur;
best_aligned = aligned;
best_delta = delta;
best_fit = avail - (units + delta);
#ifdef SLOB_BEST_FIT_ALG
}
if (slob_last(cur)) {
if (best_cur != NULL) {
#endif
slob_t *best_next = NULL;
slobidx_t best_avail = slob_units(best_cur);
if (best_delta) { /* need to fragment head to align? */
best_next = slob_next(best_cur);
set_slob(best_aligned, best_avail - best_delta, best_next);
set_slob(best_cur, best_delta, best_aligned);
best_prev = best_cur;
best_cur = best_aligned;
best_avail = slob_units(best_cur);
}
best_next = slob_next(best_cur);
if (best_avail == units) { /* exact fit? unlink. */
if (best_prev)
set_slob(best_prev, slob_units(best_prev), best_next);
else
sp->free = best_next;
} else { /* fragment */
if (best_prev)
set_slob(best_prev, slob_units(best_prev), best_cur + units);
else
sp->free = best_cur + units;
set_slob(best_cur + units, best_avail - units, best_next);
}
sp->units -= units;
if (!sp->units)
clear_slob_page_free(sp);
return best_cur;
#ifdef SLOB_BEST_FIT_ALG
}
#else
}
if (slob_last(cur)) {
#endif
return NULL;
}
}
}
/*
* The helper function, slob_page_best_fit_check, goes
* through the page's list of blocks and returns a number.
* The number will either be -1, 0, or some positive integer. -1
* means that there is no big enough block. 0 means a perfect
* fitted block. Any positive integer represents the amount
* that will be left over in the block if allocation happens. We
* either want this number to be 0 or as low as possible for
* best-fit algorithm.
*/
static int slob_page_best_fit_check(struct slob_page *sp, size_t size, int align)
{
slob_t *prev, *cur, *aligned = NULL;
int delta = 0, units = SLOB_UNITS(size);
slob_t *best_cur = NULL;
slobidx_t best_fit = 0;
for (prev = NULL, cur = sp->free; ; prev = cur, cur = slob_next(cur)) {
slobidx_t avail = slob_units(cur);
if (align) {
aligned = (slob_t *)ALIGN((unsigned long)cur, align);
delta = aligned - cur;
}
if (avail >= units + delta && (best_cur == NULL || avail - (units + delta) < best_fit) ) { /* room enough? */
best_cur = cur;
best_fit = avail - (units + delta);
if(best_fit == 0)
return 0;
}
if (slob_last(cur)) {
if (best_cur != NULL)
return best_fit;
return -1;
}
}
}
