lkml.org 
[lkml]   [2003]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Is there a "make hole" (truncate in middle) syscall?
    On Thu, 11 December 2003 14:32:12 -0600, Rob Landley wrote:
    > On Thursday 11 December 2003 13:48, Jörn Engel wrote:
    > >
    > > If you really do it, please don't add a syscall for it. Simply check
    > > each written page if it is completely filled with zero. (This will be
    > > a very quick check for most pages, as they will contain something
    > > nonzero in the first couple of words)
    >
    > Cache poisoning, streaming writes to large RAID arrays... There are about 8
    > zllion reasons not to do this. Really. (It defeats the whole purpose of
    > DMA, doesn't it?)

    Yes, the obvious and stupid implementation has a ton of problems.
    Most likely the right approach is some sort of background deamon
    (garbage collector, defragmenter, journald, whatever you may call it)
    that does exacly this even after the fact for the last unchecked
    writes. Asyncronous under load, possibly even synchronous when almost
    idle.

    A stupid implementation would still help for some workload (few, while
    hurting many) and already get the code tested, so even a stupid
    implementation helps.

    Jörn

    --
    There's nothing better for promoting creativity in a medium than
    making an audience feel "Hmm ­ I could do better than that!"
    -- Douglas Adams in a slashdot interview
    -
    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: 2005-03-22 13:59    [W:3.215 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site