lkml.org 
[lkml]   [2011]   [Dec]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH RFC] IPv6: Avoid taking write lock for /proc/net/ipv6_route
    From
    On Fri, Dec 30, 2011 at 4:09 PM, David Miller <davem@davemloft.net> wrote:
    > From: Josh Hunt <joshhunt00@gmail.com>
    > Date: Wed, 28 Dec 2011 17:23:07 -0600
    >
    >> lock_stat shows taking the write lock is causing the slowdown. Using
    >> this info I decided to write a version of fib6_clean_all() which
    >> replaces write_lock_bh(&table->tb6_lock) with
    >> read_lock_bh(&table->tb6_lock). With this new function I see the same
    >> results as with my rtnetlink iperf test. I guess my question is what
    >> am I missing? Is there a reason you need to take the write lock when
    >> reading the route table to display to proc?
    >
    > You're not missing anything, it's just an oversight or laziness. :-)
    >
    > I've applied your patch thanks.
    >
    > Longer term we should make the ipv6 tree traversals RCU safe just
    > like net/ipv4/fib_trie.c is.  Then we can do away with even the
    > read locks for read-only traversals.
    >

    Thanks David. Are you aware if anyone has started the work to make
    IPv6 traversals RCU safe?
    --
    Josh
    --
    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: 2011-12-31 20:53    [W:0.024 / U:0.168 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site