Files
zinnia/mem/amap.c
T
2026-10-25 17:07:40 +01:00

113 lines
2.8 KiB
C

// SPDX-License-Identifier: ISC
#include <zinnia/alloc.h>
#include <zinnia/amap.h>
#include <zinnia/utils.h>
#include <string.h>
errno_t anon_new(struct page* src, struct vm_anon** out) {
struct vm_anon* anon = mem_alloc(sizeof(struct vm_anon), 0);
if (!anon)
return ENOMEM;
struct page* page;
errno_t status = page_alloc(src ? ALLOC_NOZERO : 0, &page);
if (status) {
mem_free(anon);
return status;
}
if (src)
memcpy(HHDM_PTR(vm_page_addr(page)), HHDM_PTR(vm_page_addr(src)), arch_mem_page_size());
atomic_fetch_or(&page->flags, PAGE_ANON, ATOMIC_RELAXED);
page->obj.owner = anon;
atomic_store(&anon->rc, 1, ATOMIC_RELAXED);
anon->page = page;
*out = anon;
return 0;
}
void anon_ref(struct vm_anon* anon) {
atomic_fetch_add(&anon->rc, 1, ATOMIC_RELAXED);
}
void anon_unref(struct vm_anon* anon) {
if (atomic_fetch_sub(&anon->rc, 1, ATOMIC_RELEASE) != 1)
return;
atomic_fence(ATOMIC_ACQUIRE);
page_unhold(anon->page);
mem_free(anon);
}
errno_t amap_new(struct amap** out) {
struct amap* amap = mem_alloc(sizeof(struct amap), 0);
if (!amap)
return ENOMEM;
refcount_init(&amap->rc);
mutex_init(&amap->lock);
radix_init(&amap->anons);
*out = amap;
return 0;
}
void amap_ref(struct amap* amap) {
refcount_inc(&amap->rc);
}
void amap_unref(struct amap* amap) {
if (!refcount_dec(&amap->rc))
return;
struct vm_anon* batch[32];
uint64_t slots[32];
size_t found;
while ((found = radix_gang_lookup(&amap->anons, 0, ARRAY_SIZE(batch), (void**)batch, slots)) != 0) {
for (size_t i = 0; i < found; i++) {
radix_remove(&amap->anons, slots[i]);
anon_unref(batch[i]);
}
}
radix_destroy(&amap->anons);
mem_free(amap);
}
bool amap_is_shared(struct amap* amap) {
return atomic_load(&amap->rc.count, ATOMIC_ACQUIRE) != 1;
}
errno_t amap_copy(struct amap* src, size_t offset, size_t num_slots, struct amap** out) {
struct amap* copy;
errno_t status = amap_new(&copy);
if (status)
return status;
struct vm_anon* batch[32];
uint64_t slots[32];
uint64_t next = offset;
mutex_lock(&src->lock);
while (status == 0) {
const size_t found = radix_gang_lookup(&src->anons, next, ARRAY_SIZE(batch), (void**)batch, slots);
if (found == 0)
break;
for (size_t i = 0; i < found && status == 0; i++) {
if (slots[i] >= offset + num_slots)
goto done;
status = radix_insert(&copy->anons, slots[i] - offset, batch[i]);
if (!status)
anon_ref(batch[i]);
}
next = slots[found - 1] + 1;
}
done:
mutex_unlock(&src->lock);
if (status) {
amap_unref(copy);
return status;
}
*out = copy;
return 0;
}