imported from https://holmeshe.me/understanding-memcached-source-code-I/

slabs_init@slabs.c

void slabs_init(const size_t limit, const double factor, const bool prealloc, const uint32_t *slab_sizes) {
    int i = POWER_SMALLEST /* scr: 1 */ - 1;
    unsigned int size = sizeof(item) + settings.chunk_size; // scr: ---------> b 1)
...
    memset(slabclass, 0, sizeof(slabclass));

    while (++i < MAX_NUMBER_OF_SLAB_CLASSES-1) {
        if (slab_sizes != NULL) { // scr: -----------------------------------> a 1)
            if (slab_sizes[i-1] == 0)
                break;
            size = slab_sizes[i-1];
        } else if (size >= settings.item_size_max / factor) {
            break;
        }
        /* Make sure items are always n-byte aligned */
        if (size % CHUNK_ALIGN_BYTES) // scr: ---------------------------------> 2)
            size += CHUNK_ALIGN_BYTES - (size % CHUNK_ALIGN_BYTES);

        slabclass[i].size = size;
        slabclass[i].perslab = settings.item_size_max / slabclass[i].size; // -> 3)
        if (slab_sizes == NULL)
            size *= factor; // scr: -----------------------------------------> b 4)
        if (settings.verbose > 1) {
            fprintf(stderr, "slab class %3d: chunk size %9u perslab %7u\n",
                    i, slabclass[i].size, slabclass[i].perslab);
        }
    }
    // scr: -------------------------------------------------------------------> 5)
    power_largest = i;
    slabclass[power_largest].size = settings.item_size_max;
    slabclass[power_largest].perslab = 1;
...
}