• Yuval Shaia's avatar
    IB/ipoib: Scatter-Gather support in connected mode · c4268778
    Yuval Shaia authored
    By default, IPoIB-CM driver uses 64k MTU. Larger MTU gives better
    performance.
    This MTU plus overhead puts the memory allocation for IP based packets at
    32 4k pages (order 5), which have to be contiguous.
    When the system memory under pressure, it was observed that allocating 128k
    contiguous physical memory is difficult and causes serious errors (such as
    system becomes unusable).
    
    This enhancement resolve the issue by removing the physically contiguous
    memory requirement using Scatter/Gather feature that exists in Linux stack.
    
    With this fix Scatter-Gather will be supported also in connected mode.
    
    This change reverts some of the change made in commit e112373f
    ("IPoIB/cm: Reduce connected mode TX object size").
    
    The ability to use SG in IPoIB CM is possible because the coupling
    between NETIF_F_SG and NETIF_F_CSUM was removed in commit
    ec5f0615 ("net: Kill link between CSUM and SG features.")
    Signed-off-by: default avatarYuval Shaia <yuval.shaia@oracle.com>
    Acked-by: default avatarChristian Marie <christian@ponies.io>
    Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
    c4268778
ipoib_ib.c 27.7 KB