lkml.org 
[lkml]   [2004]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [BENCHMARK] nproc: netlink access to /proc information
    On Sun, 29 Aug 2004 12:17:07 -0700, William Lee Irwin III wrote:
    >> Introducing another whole-tasklist scan, even if feasible, is probably
    >> not a good idea.

    On Sun, Aug 29, 2004 at 09:49:26PM +0200, Roger Luethi wrote:
    > I'm not sure whether I should participate in that discussion. I'll risk
    > discrediting nproc with wild speculations on a subject I haven't really
    > looked into yet. Ah well...

    There isn't much to speculate about here; reducing the arrival rate to
    tasklist_lock is okay, but it can't be held forever or use unbounded
    allocations or anything like that.


    On Sun, Aug 29, 2004 at 09:49:26PM +0200, Roger Luethi wrote:
    > As far as nproc (and process monitoring) is concerned, we aren't really
    > interested in walking a complete process list. All we care about is
    > which pids exist right now. How about a bit field, maintained by the
    > kernel, to indicate for each pid whether it exists or not? This would
    > amount to 4 KiB by default and 512 KiB for PID_MAX_LIMIT (4 million
    > processes). Maintenance cost would be one atomic bit operation per
    > process creation/deletion. No contested locks.
    > The list for the nproc user could be prepared based on the bit field
    > (or simply memcpy'd), no tasklist_lock or walking linked lists required.
    > What am I missing?

    The pid bitmap could be exported to userspace rather easily.


    -- wli
    -
    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 14:05    [W:3.211 / U:2.352 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site