99 lines
3.0 KiB
C
99 lines
3.0 KiB
C
#define pr_fmt(fmt) "[alloc]: " fmt
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//#define DEBUG
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#include "alloc.h"
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#include "errno.h"
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#include "list.h"
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#include "math.h"
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#include "mem.h"
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#include "vga.h"
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// Slab will contains object from sizeof(void *) to PAGE_SIZE/2 by pow2
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#define SLUB_SIZE (PAGE_SHIFT - 1)
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struct slabDesc *slubArray[SLUB_SIZE];
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int initSlabDesc(struct slabDesc **desc, size_t size);
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static int formatPage(struct slabDesc *desc, size_t size);
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int initSlab(void)
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{
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uint start = log2(sizeof(void *));
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for (uint i = start; i < SLUB_SIZE; i++) {
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if (initSlabDesc(&slubArray[i - start], 1U << i))
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return ENOMEM;
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}
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return 0;
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}
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int initSlabDesc(struct slabDesc **desc, size_t size)
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{
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if (size > PAGE_SIZE)
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return ENOENT;
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paddr_t alloc = allocPhyPage();
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if (alloc == (paddr_t)NULL)
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return ENOMEM;
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if (pageMap((vaddr_t)alloc, alloc, PAGING_MEM_WRITE)) {
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return ENOMEM;
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}
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*desc = (struct slabDesc *)alloc;
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list_singleton(*desc, *desc);
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(*desc)->page = (vaddr_t)alloc;
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(*desc)->full = 0;
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(*desc)->freeEl = (char *)(*desc) + sizeof(struct slabDesc);
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(*desc)->size = size;
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pr_devel("got page %d for size %d first %d", alloc, size, (*desc)->freeEl);
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return formatPage((*desc), size);
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}
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static int formatPage(struct slabDesc *desc, size_t size)
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{
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char *cur = (char *)desc + sizeof(struct slabDesc);
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ulong i;
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for (i = 0; i < ((PAGE_SIZE - sizeof(struct slabDesc)) / size - 1); i++) {
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*((vaddr_t *)cur) = (vaddr_t)cur + size;
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cur += size;
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}
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*((vaddr_t *)cur) = (vaddr_t)NULL;
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pr_devel("last at %d allocated %d\n", cur, i + 1);
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return 0;
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}
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static void *allocFromSlab(struct slabDesc *slab)
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{
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vaddr_t *next = slab->freeEl;
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if (*next == (vaddr_t)NULL) {
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pr_devel("Slab %d full\n", slab);
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slab->full = 1;
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} else {
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slab->freeEl = (void *)(*next);
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}
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return (void *)next;
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}
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void *malloc(size_t size)
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{
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if (size > (1U << SLUB_SIZE)) {
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printf("implement malloc for big size\n");
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return NULL;
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}
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uint slubIdx = 0;
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while (size > slubArray[slubIdx]->size) {
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slubIdx++;
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}
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struct slabDesc *slab;
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int slabIdx;
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list_foreach(slubArray[slubIdx], slab, slabIdx)
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{
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if (!slab->full) {
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pr_devel("found place in slub %d at idx %d \n", slubIdx, slabIdx);
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return allocFromSlab(slab);
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}
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}
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if (!list_foreach_early_break(slubArray[slubIdx], slab, slabIdx)) {
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struct slabDesc *newSlab;
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initSlabDesc(&newSlab, slab->size);
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list_add_head(slubArray[slubIdx], newSlab);
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return allocFromSlab(newSlab);
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}
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return NULL;
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}
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