• Heiko Carstens's avatar
    s390/vmcp: make use of contiguous memory allocator · 3f429842
    Heiko Carstens authored
    
    
    If memory is fragmented it is unlikely that large order memory
    allocations succeed. This has been an issue with the vmcp device
    driver since a long time, since it requires large physical contiguous
    memory ares for large responses.
    
    To hopefully resolve this issue make use of the contiguous memory
    allocator (cma). This patch adds a vmcp specific vmcp cma area with a
    default size of 4MB. The size can be changed either via the
    VMCP_CMA_SIZE config option at compile time or with the "vmcp_cma"
    kernel parameter (e.g. "vmcp_cma=16m").
    
    For any vmcp response buffers larger than 16k memory from the cma area
    will be allocated. If such an allocation fails, there is a fallback to
    the buddy allocator.
    Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    3f429842
kernel-parameters.txt 158 KB