• David Chinner's avatar
    [XFS] Radix tree based inode caching · da353b0d
    David Chinner authored
    One of the perpetual scaling problems XFS has is indexing it's incore
    inodes. We currently uses hashes and the default hash sizes chosen can
    only ever be a tradeoff between memory consumption and the maximum
    realistic size of the cache.
    As a result, anyone who has millions of inodes cached on a filesystem
    needs to tunes the size of the cache via the ihashsize mount option to
    allow decent scalability with inode cache operations.
    A further problem is the separate inode cluster hash, whose size is based
    on the ihashsize but is smaller, and so under certain conditions (sparse
    cluster cache population) this can become a limitation long before the
    inode hash is causing issues.
    The following patchset removes the inode hash and cluster hash and
    replaces them with radix trees to avoid the scalability limitations of the
    hashes. It also reduces the size of the inodes by 3 pointers....
    SGI-PV: 969561
    SGI-Modid: xfs-linux-melb:xfs-kern:29481a
    Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
    Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
    Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
xfs_trans_extfree.c 3.62 KB