• Roger Pau Monne's avatar
    xen-blkback: use balloon pages for all mappings · c6cc142d
    Roger Pau Monne authored
    Using balloon pages for all granted pages allows us to simplify the
    logic in blkback, especially in the xen_blkbk_map function, since now
    we can decide if we want to map a grant persistently or not after we
    have actually mapped it. This could not be done before because
    persistent grants used ballooned pages, whereas non-persistent grants
    used pages from the kernel.
    
    This patch also introduces several changes, the first one is that the
    list of free pages is no longer global, now each blkback instance has
    it's own list of free pages that can be used to map grants. Also, a
    run time parameter (max_buffer_pages) has been added in order to tune
    the maximum number of free pages each blkback instance will keep in
    it's buffer.
    Signed-off-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
    Cc: xen-devel@lists.xen.org
    Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    c6cc142d
xenbus.c 19.5 KB