lkml.org 
[lkml]   [2000]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Overcommitable memory??
On Mon, 20 Mar 2000, James Sutherland wrote:
>On Mon, 20 Mar 2000 05:39:48 -0600, you wrote:
>>On Sun, 19 Mar 2000, David Whysong wrote:
>
>Just send SIGTERM. This gives them an opportunity to exit gracefully.
>If they ignore it, SIGKILL them.
>
>>>Once we are OOM, you can't give user-space any choices.
>>
>>YOU ARN'T OOM - a specific user is out of resources, not a catastrophic
>>failure.

A user being out of (memory) resources shares many of the same problems of
a system that is OOM. You still need to kill one or more user processes,
and you can't give the user the choice, because the user might decide to
keep on running.

>SOMETHING (the user, the process, the system, the cluster, whatever)
>is out of resources, so something has to give. Which unit has run out
>of resources doesn't matter - the issue is how we handle running out
>of resources in some category.

Precisely.

>>>I don't like resource limits. Using resource limits is similar to not
>>>having memory overcommit -- you waste a lot of system resources "just in
>>>case", the kernel needs to do a lot more accounting, and it's just
>>>horribly inefficient.
>>
>>Resource limits CAN prevent the OOM condition if
>> 1. the sum of all concurrent users is <= total resources
>> 2. users are not allowed to exceed their quota
>
>That's an extremely restrictive approach, but appropriate in some
>cases. We need those resource limits - but what's this got to do with
>overcommit??

Preventing system OOM using resource limits is equivalent to disabling
overcommit. You have to restrict each of N users to 1/N of the total
system memory.


Dave

David Whysong dwhysong@physics.ucsb.edu
Astrophysics graduate student University of California, Santa Barbara
My public PGP keys are on my web page - http://www.physics.ucsb.edu/~dwhysong
DSS PGP Key 0x903F5BD6 : FE78 91FE 4508 106F 7C88 1706 B792 6995 903F 5BD6
D-H PGP key 0x5DAB0F91 : BC33 0F36 FCCD E72C 441F 663A 72ED 7FB7 5DAB 0F91


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:57    [W:0.140 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site