lkml.org 
[lkml]   [2007]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Intel-IOMMU 02/10] Library routine for pre-allocat pool handling
    On Mon, 11 Jun 2007 13:44:42 -0700
    "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com> wrote:

    > In the first implementation of ours, we had used mempools api's to
    > allocate memory and we were told that mempools with GFP_ATOMIC is
    > useless and hence in the second implementation we came up with
    > resource pools ( which is preallocate pools) and again as I understand
    > the argument is why create another when we have slab allocation which
    > is similar to this resource pools.

    Odd. mempool with GFP_ATOMIC is basically equivalent to your
    resource-pools, isn't it?: we'll try the slab allocator and if that failed,
    fall back to the reserves.

    It's missing the recharge-from-a-kernel-thread functionality but that can be
    added easily enough if it's useful. It's slightly abusive of the mempool
    philosophy, but it's probably better to do that than to create a new and
    very-similar thing.

    > Hence, can I assume that the conclusion of this
    > discussion is to use kmem_cache_alloc() functions
    > to allocate memory in dma_map_{single|sg} API's?
    >
    > Again, if dma_map_{single|sg} API's fails due to
    > failure to allocate memory, the only thing that can
    > be done is to panic as this is what few of the other
    > IOMMU implementation is doing today.

    If the only option is to panic then something's busted. If it's network IO
    then there should be a way of dropping the frame. If it's disk IO then we
    should report the failure and cause an IO error.

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-06-11 23:17    [W:5.661 / U:0.084 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site