lkml.org 
[lkml]   [2005]   [May]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: semaphore understanding: sys_semtimedop()
    On Mon, 16 May 2005 22:17:04 +0200 Patrick Plattes wrote:

    | Hello,
    |
    | i have a question about this little code snippet, found in
    | sys_semtimedop() (ipc/sem.c):
    |
    | for (sop = sops; sop < sops + nsops; sop++) {
    | if (sop->sem_num >= max)
    | max = sop->sem_num;
    | if (sop->sem_flg & SEM_UNDO)
    | undos++;
    | if (sop->sem_op < 0)
    | decrease = 1;
    | if (sop->sem_op > 0)
    | alter = 1;
    | }
    | alter |= decrease;
    |
    | The variable decrease will never be used again in this
    | function, so why this intricate code? Isn't this much easier and works
    | also:
    |
    | for (sop = sops; sop < sops + nsops; sop++) {
    | if (sop->sem_num >= max)
    | max = sop->sem_num;
    | if (sop->sem_flg & SEM_UNDO)
    | undos++;
    | if (sop->sem_op != 0)
    | alter = 1;
    | }
    |
    | Maybe i'm totally wrong, so please correct me and don't shoot me up,
    | 'cause i'm not a os developer.

    Looks like a reasonable and correct optimization to me.

    Let's see what Manfred thinks or has to say...

    ---
    ~Randy
    -
    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: 2005-05-22 07:25    [W:0.021 / U:10.296 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site