• Steven Whitehouse's avatar
    [GFS2] Reduce inode size by moving i_alloc out of line · 6dbd8224
    Steven Whitehouse authored
    It is possible to reduce the size of GFS2 inodes by taking the i_alloc
    structure out of the gfs2_inode. This patch allocates the i_alloc
    structure whenever its needed, and frees it afterward. This decreases
    the amount of low memory we use at the expense of requiring a memory
    allocation for each page or partial page that we write. A quick test
    with postmark shows that the overhead is not measurable and I also note
    that OCFS2 use the same approach.
    In the future I'd like to solve the problem by shrinking down the size
    of the members of the i_alloc structure, but for now, this reduces the
    immediate problem of using too much low-memory on x86 and doesn't add
    too much overhead.
    Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>