Question about buffer size calculation in _php_stream_copy_to_mem_ex

I see the following in _php_stream_copy_to_mem_ex in main/streams/streams.c int step = CHUNK_SIZE; int min_room = CHUNK_SIZE / 4; (..stuff deleted..) /* avoid many reallocs by allocating a good sized chunk to begin with, if * we can. Note that the stream may be filtered, in which case the stat * result may be inaccurate, as the filter may inflate or deflate the * number of bytes that we can read. In order to avoid an upsize followed * by a downsize of the buffer, overestimate by the step size (which is * 2K). */ if (php_stream_stat(src, &ssbuf) == 0 && ssbuf.sb.st_size > 0) { max_len = ssbuf.sb.st_size + step; } else { max_len = step; } According to the comment the intention is to overestimate by 2K, but CHUNK_SIZE = 8192 and that leads quite a bit of over-allocation of memory. Is the following a better setting for max_len in the if block? max_len = (((ssbuf.sb.st_size + min_room)/step) + 1) * step; The following are sample values that show the current vs new size calculation. ssbuf.sb.st_size, max_len (current), max_len (new) ( 100, 8292, 8192) ( 1000, 9192, 8192) ( 5000, 13192, 8192) ( 7000, 15192, 16384) ( 13000, 21192, 16384) ( 22000, 30192, 24576) thanks, arvi