[lkml]   [2009]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [patch 016/104] epoll: introduce resource usage limits
On Fri, Jan 23, 2009 at 6:06 PM, Greg KH <> wrote:
> On Fri, Jan 23, 2009 at 08:47:45PM +1100, Bron Gondwana wrote:
>> On Thu, 22 Jan 2009 21:16 -0800, "Greg KH" <> wrote:
>> > > This is a kvm virtual machine running on a reasonably beefy external box, but
>> > > with 2Gb RAM allocated to the mx instance because that's all kvm would let me
>> > > use last time I checked. We're using KVM so the local copy of the database is
>> > > a little further away from the "internet facing side" and so we can build each
>> > > machine with our standard FAI setup.
>> >
>> > I would suggest just changing this default value then, it's a simple
>> > userspace configuration item, and for your boxes, it sounds like a
>> > larger value would be more suitable.
>> Yes - I've pushed it up to 4096 now. Should be plenty!
>> I guess Postfix is a bit of an odd case here. It runs lots of processes, yet
>> uses epoll within many of them as well - sort of a historical design in some ways,
>> but also to enforce maximum privilege separation with many of the daemons able to
>> be run under chroot with limited capabilities.
>> So I guess I have a few questions left:
>> 1) is this value ever supposed to be hit in practice by non-malicious software?
>> If not, it appears 128 is too low.
> It does appear a bit low. What looks to you like a good value to use as
> a default?
>> 2) if we're going to stick with 128, is there any way to query the kernel as to how
>> close to the limit it's getting? As an example, our system checks poll
>> /proc/sys/fs/file-max every 2 minutes, and warn us if its getting "full".
> Good idea, we should report this somewhere for the very reasons you
> suggest. Can you write up a patch to do this? If not, I'll see what I
> can do.

Why not using a ulimit for this kind of stuff ?



 \ /
  Last update: 2009-01-23 18:27    [W:0.207 / U:0.008 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site