size_classes.cpp

/*
 * Copyright (C) 2019 Ricardo Leite. All rights reserved.
 * Licenced under the MIT licence. See COPYING file in the project root for
 * details.
 */

#include "lrmalloc_internal.h"
#include "size_classes.h"

#include "log.h"

#define SIZE_CLASS_bin_yes(blockSize, pages) { blockSize, pages * PAGE },
#define SIZE_CLASS_bin_no(blockSize, pages)

#define SC(index, lg_grp, lg_delta, ndelta, psz, bin, pgs, lg_delta_lookup) \
    SIZE_CLASS_bin_##bin((1U << lg_grp) + (ndelta << lg_delta), pgs)

SizeClassData SizeClasses[MAX_SZ_IDX] = { { 0, 0 }, SIZE_CLASSES };

size_t SizeClassLookup[MAX_SZ + 1] = { 0 };

void InitSizeClass()
{
    // fill blockNum and cacheBlockNum
    for (size_t scIdx = 1; scIdx < MAX_SZ_IDX; ++scIdx) {
        SizeClassData& sc = SizeClasses[scIdx];
        // blockNum calc
        sc.blockNum = SB_SIZE / sc.blockSize;
        // cacheBlockNum calc
        sc.cacheBlockNum = sc.blockNum * 1;
        ASSERT(sc.blockNum > 0);
        ASSERT(sc.blockNum <= MAX_BLOCK_NUM);
        ASSERT(sc.blockNum >= sc.cacheBlockNum);
    }

    // first size class reserved for large allocations
    size_t lookupIdx = 0;
    for (size_t scIdx = 1; scIdx < MAX_SZ_IDX; ++scIdx) {
        SizeClassData const& sc = SizeClasses[scIdx];
        size_t blockSize = sc.blockSize;
        while (lookupIdx <= blockSize) {
            SizeClassLookup[lookupIdx] = scIdx;
            ++lookupIdx;
        }
    }
}