lkml.org 
[lkml]   [2012]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH for 3.2.34] memcg: do not trigger OOM from add_to_page_cache_locked
    On Mon 10-12-12 02:20:38, azurIt wrote:
    [...]
    > Michal,

    Hi,

    > this was printing so many debug messages to console that the whole
    > server hangs

    Hmm, this is _really_ surprising. The latest patch didn't add any new
    logging actually. It just enahanced messages which were already printed
    out previously + changed few functions to be not inlined so they show up
    in the traces. So the only explanation is that the workload has changed
    or the patches got misapplied.

    > and i had to hard reset it after several minutes :( Sorry
    > but i cannot test such a things in production. There's no problem with
    > one soft reset which takes 4 minutes but this hard reset creates about
    > 20 minutes outage (mainly cos of disk quotas checking).

    Understood.

    > Last logged message:
    >
    > Dec 10 02:03:29 server01 kernel: [ 220.366486] grsec: From 141.105.120.152: bruteforce prevention initiated for the next 30 minutes or until service restarted, stalling each fork 30 seconds. Please investigate the crash report for /usr/lib/apache2/mpm-itk/apache2[apache2:3586] uid/euid:1258/1258 gid/egid:100/100, parent /usr/lib/apache2/mpm-itk/apache2[apache2:2142] uid/euid:0/0 gid/egid:0/0

    This explains why you have seen your machine hung. I am not familiar
    with grsec but stalling each fork 30s sounds really bad.

    Anyway this will not help me much. Do you happen to still have any of
    those logged traces from the last run?

    Apart from that. If my current understanding is correct then this is
    related to transparent huge pages (and leaking charge to the page fault
    handler). Do you see the same problem if you disable THP before you
    start your workload? (echo never > /sys/kernel/mm/transparent_hugepage/enabled)
    --
    Michal Hocko
    SUSE Labs


    \
     
     \ /
      Last update: 2012-12-10 11:21    [W:3.926 / U:0.576 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site