952     * `av': An array of chunks serving as bin headers for consolidated
953        chunks. Each bin is doubly linked.  The bins are approximately
961        The chunks in each bin are maintained in decreasing sorted order by
975        included in any bin, is used only if no other chunk is
979     * `last_remainder': A bin holding only the remainder of the
980        most recently split (non-top) chunk. This bin is checked
1130     malloc_chunk. (This way, the fd/bk offsets for linking bin heads
1136     directly in the code, but instead via bin access macros.
1138     Bin layout:
1146      1 bin  of size what's left
1153     although `top' is never properly linked to its bin since it is
1183    Because top initially points to its own bin with initial
1251    Requests are `small' if both the corresponding and the next bin are small
1260     structure is used for bin-by-bin searching.  `binblocks' is a
1272 /* bin<->block macros */
1490   Linking chunks in bin lists.
1495   Place chunk p of size s in its bin, in size order,
1548 /* Clear the last_remainder bin */
1844       1. The bin corresponding to the request size is scanned, and if
1902   int       idx;                     /* index for bin traversal */  in mALLOc()
1903   mbinptr   bin;                     /* associated bin */  in mALLOc()
1906   int       remainder_index;         /* its bin index */  in mALLOc()
1908   int       startidx;                /* first bin of a traversed block */  in mALLOc()
1924   /* Check for exact match in a bin */  in mALLOc()
1953     idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */  in mALLOc()
1959     bin = bin_at(idx);  in mALLOc()
1961     for (victim = last(bin); victim != bin; victim = victim->bk)  in mALLOc()
2015     /* Else place in bin */  in mALLOc()
2046       q = bin = bin_at(idx);  in mALLOc()
2048       /* For each bin in this block ... */  in mALLOc()
2053         for (victim = last(bin); victim != bin; victim = victim->bk)  in mALLOc()
2082        bin = next_bin(bin);  in mALLOc()
2087            bin = next_bin(bin);  in mALLOc()
2197   int       idx;       /* its bin index */  in fREe()
3211       * malloc: swap order of clean-bin strategy;
3214       * Use bin counts as a guide to preallocation
3215       * Occasionally bin return list chunks in first scan
3219       * faster bin computation & slightly different binning