4k issue on MD device block size

["bmoon" <bo@anthologysolutions.com>]

Hello,

Please provide me an advice on  the following issues;

I'd like to use 4k block size for both MD super block I/O and regular file
I/O,
which will improve the performance.

Q1: I noticed that it set the "blksize_size" to 4k for MD SB I/O but it use
1K
       for the regular file I/O.  It usually set the size to 1k at system
init by "md-init",
       then it set to 4k for MD SB I/O later. I could not find the place
that set it
      back to 1k.   However, it changes to 1 k????  How?

Q2: I modified md.c to use the 4k blksize_size. It works but sometimes it
crash.
      System "BLOCK_SIZE" is still 1k, and my hd device blksize_size=1k,
too.
      I changed ONLY 1024 to 4096 on every occurences on md.c.

     What am I missing?

Thanks in advance,

Bo