holmeshe

typedef struct {
    unsigned int size;      /* sizes of items */
    unsigned int perslab;   /* how many items per slab */

    void *slots;           /* list of item ptrs */
    unsigned int sl_curr;   /* total free items in list */

    unsigned int slabs;     /* how many slabs were allocated for this class */

    void **slab_list;       /* array of slab pointers */

holmeshe

void slabs_init(const size_t limit, const double factor, const bool prealloc, const uint32_t *slab_sizes) {
...
    mem_limit = limit; // scr: here
...

holmeshe

static size_t mem_limit = 0;
...
  settings.maxbytes = 64 * 1024 * 1024; /* default is 64MB */
...
        case 'm':
            settings.maxbytes = ((size_t)atoi(optarg)) * 1024 * 1024;
            break;
...

holmeshe

...
   bool preallocate = false;
...
        case 'L' :
            if (enable_large_pages() == 0) {
                preallocate = true;
            } else {
                fprintf(stderr, "Cannot enable large pages on this system\n"
                    "(There is no Linux support as of this version)\n");
                return 1;

holmeshe

static int do_slabs_newslab(const unsigned int id) {
    slabclass_t *p = &slabclass[id]; // scr: ----------------------------> 1)
    slabclass_t *g = &slabclass[SLAB_GLOBAL_PAGE_POOL]; // scr: ---------> *)
    int len = settings.slab_reassign ? settings.item_size_max // scr: ---> 2)
        : p->size * p->perslab;
    char *ptr;

    if ((mem_limit && mem_malloced + len > mem_limit && p->slabs > 0 // -> 3)
         && g->slabs == 0)) {
        mem_limit_reached = true;

holmeshe

static int grow_slab_list (const unsigned int id) {
    slabclass_t *p = &slabclass[id];
    if (p->slabs == p->list_size) {
        size_t new_size =  (p->list_size != 0) ? p->list_size * 2 : 16;
        void *new_list = realloc(p->slab_list, new_size * sizeof(void *));
        if (new_list == 0) return 0;
        p->list_size = new_size;
        p->slab_list = new_list;
    }
    return 1;

holmeshe

static void split_slab_page_into_freelist(char *ptr, const unsigned int id) {
    slabclass_t *p = &slabclass[id];
    int x;
    for (x = 0; x < p->perslab; x++) {
        do_slabs_free(ptr, 0, id);
        ptr += p->size;
    }
}

holmeshe

static void do_slabs_free(void *ptr, const size_t size, unsigned int id) {
    slabclass_t *p;
    item *it;
...
    p = &slabclass[id];

    it = (item *)ptr;
    it->it_flags = ITEM_SLABBED; // scr: ---------------> 1)
    it->slabs_clsid = 0;
    it->prev = 0; // scr: ------------------------------> 2)

holmeshe

void slabs_init(const size_t limit, const double factor, const bool prealloc, const uint32_t *slab_sizes) {
...
    if (prealloc) {
        slabs_preallocate(power_largest);
    }
}

holmeshe

static void slabs_preallocate (const unsigned int maxslabs) {
    int i;
    unsigned int prealloc = 0;

    /* pre-allocate a 1MB slab in every size class so people don't get
       confused by non-intuitive "SERVER_ERROR out of memory"
       messages.  this is the most common question on the mailing
       list.  if you really don't want this, you can rebuild without
       these three lines.  */