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slab: deallocation

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Matheus
2023-04-18 23:48:41 -03:00
parent 81a50399af
commit f5c76c5ff8
1 changed files with 77 additions and 1 deletions
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kernel-src/mm/slab.c
+77 -1
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@@ -76,15 +76,54 @@ static void *takeobject(scache_t *cache, slab_t *slab) {
if (slab->free == NULL)
return NULL;
void *objend = slab->free;
void **objend = slab->free;
slab->free = *slab->free;
slab->used += 1;
*objend = NULL;
if (cache->size < SLAB_INDIRECT_CUTOFF)
return (void *)((uintptr_t)objend - cache->size);
else
return (void *)((uintptr_t)slab->base + ((uintptr_t)objend - ROUND_DOWN((uintptr_t)slab, PAGE_SIZE)) / sizeof(void **) * cache->truesize);
}
// frees an object and returns the slab the object belongs to
static slab_t *returnobject(scache_t *cache, void *obj) {
slab_t *slab = NULL;
void **freeptr = NULL;
if (cache->size < SLAB_INDIRECT_CUTOFF) {
slab = (slab_t *)(ROUND_DOWN((uintptr_t)obj, PAGE_SIZE) + SLAB_PAGE_OFFSET);
freeptr = (void **)((uintptr_t)obj + cache->size);
__assert(*freeptr == NULL);
} else {
slab = cache->full;
bool partial = false;
while (slab) {
void *top = (void *)((uintptr_t)slab->base + cache->slabobjcount * cache->truesize);
if (obj >= slab->base && obj < top)
break;
if (slab->next == NULL && partial == false) {
slab = cache->partial;
partial = true;
} else {
slab = slab->next;
}
}
__assert(slab);
uintmax_t objn = ((uintptr_t)obj - (uintptr_t)slab->base) / cache->truesize;
void **base = (void **)ROUND_DOWN((uintptr_t)obj, PAGE_SIZE);
freeptr = &base[objn];
}
if (cache->dtor)
cache->dtor(cache, obj);
*freeptr = slab->free;
slab->free = freeptr;
--slab->used;
return slab;
}
void *slab_allocate(scache_t *cache) {
// TODO lock
slab_t *slab = NULL;
@@ -106,12 +145,20 @@ void *slab_allocate(scache_t *cache) {
if (slab == cache->empty) {
cache->empty = slab->next;
if (slab->prev)
slab->prev->next = slab->next;
if (slab->next)
slab->next->prev = slab->prev;
slab->next = cache->partial;
cache->partial = slab;
}
if (slab->used == cache->slabobjcount) {
cache->partial = slab->next;
if (slab->prev)
slab->prev->next = slab->next;
if (slab->next)
slab->next->prev = slab->prev;
slab->next = cache->full;
cache->full = slab;
}
@@ -121,6 +168,35 @@ void *slab_allocate(scache_t *cache) {
return ret;
}
void slab_free(scache_t *cache, void *addr) {
// TODO lock
slab_t *slab = returnobject(cache, addr);
__assert(slab);
if (slab->used == 0) {
cache->partial = slab->next;
if (slab->prev)
slab->prev->next = slab->next;
if (slab->next)
slab->next->prev = slab->prev;
slab->next = cache->empty;
cache->empty = slab;
}
if (slab->used == cache->slabobjcount - 1) {
cache->full = slab->next;
if (slab->prev)
slab->prev->next = slab->next;
if (slab->next)
slab->next->prev = slab->prev;
slab->next = cache->empty;
cache->empty = slab;
}
// TODO unlock
}
scache_t *slab_newcache(size_t size, size_t alignment, void (*ctor)(scache_t *, void *), void (*dtor)(scache_t *, void *)) {
if (alignment == 0)
alignment = 8;