[lkml]   [2006]   [Dec]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [patch 1/2] agpgart - allow user-populated memory types.
    Arjan van de Ven wrote:

    >>A short background:
    >>The current code uses vmalloc only. The potential use of kmalloc was
    >>to save memory and cpu-speed.
    >>All agp drivers expect to see a single memory chunk, so I'm not sure we
    >>want to have an array of pages. That may require rewriting a lot of code.
    >but if it's clearly the right thing.....
    >How hard can it be? there are what.. 5 or 6 AGP drivers in the kernel?
    but we would still waste a lot of memory compared to kmalloc,
    when the amount of memory needed is much less than one page, which tends
    to be
    a very common case.

    Unless we allow the first entry in the array to be the virtual adress to an
    arbitrary-sized (max one page) kmalloc() area, the rest of the entries
    can be pointers
    to pages allocated with __get_free_page().

    This would almost introduce the same level of confusion as the original
    and effectively we'd be doing virtual address translation in software
    for each access.

    >>If it's acceptable I'd like to go for the vmalloc / kmalloc flag, or at
    >>worst keep the current vmalloc only but that's such a _huge_ memory
    >>waste for small buffers. The flag was the original idea, but
    >>unfortunately the agp_memory struct is part of the drm interface, and I
    >>wasn't sure we could add a variable to it.
    >I doubt this is part of the userspace interface so for sure we can
    >change it to be right.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2006-12-19 13:51    [W:0.023 / U:41.900 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site