Re: [ckrm-tech] [PATCH] BC: resource beancounters (v4) (added user memory)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Pavel Emelianov wrote:
Balbir Singh wrote:
Pavel Emelianov wrote:
Balbir Singh wrote:
Dave Hansen wrote:
On Fri, 2006-09-08 at 11:33 +0400, Pavel Emelianov wrote:
I'm afraid we have different understandings of what a "guarantee" is.
It appears so.

Don't we?
Guarantee may be one of

  1. container will be able to touch that number of pages
  2. container will be able to sys_mmap() that number of pages
  3. container will not be killed unless it touches that number of
pages
A "death sentence" guarantee?  I like it. :)

  4. anything else

Let's decide what kind of a guarantee we want.
I think of guarantees w.r.t resources as the lower limit on the
resource.
Guarantees and limits can be thought of as the range (guarantee, limit]
for the usage of the resource.

I think of it as: "I will be allowed to use this many total pages, and
they are guaranteed not to fail."  (1), I think.  The sum of all of
the
system's guarantees must be less than or equal to the amount of free
memory on the machine.
Yes, totally agree.
Such a guarantee is really a limit and this limit is even harder than
BC's one :)

E.g. I have a node with 1Gb of ram and 10 containers with 100Mb
guarantee each.
I want to start one more. What shall I do not to break guarantees?
Don't start the new container or change the guarantees of the existing
ones
to accommodate this one :) The QoS design (done by the administrator)
should
take care of such use-cases. It would be perfectly ok to have a container
that does not care about guarantees to set their guarantee to 0 and set
their limit to the desired value. As Chandra has been stating we need two
parameters (guarantee, limit), either can be optional, but not both.
If I set up 9 groups to have 100Mb limit then I have 100Mb assured (on
1Gb node)
for the 10th one exactly. And I do not have to set up any guarantee as
it won't affect
anything. So what a guarantee parameter is needed for?

This use case works well for providing guarantee to one container. What if
I want guarantees of 100Mb and 200Mb for two containers? How do I setup
the system using limits?

Even I restrict everyone else to 700Mb. With this I cannot be sure that
the remaining 300Mb will be distributed as 100Mb and 200Mb.


--

	Balbir Singh,
	Linux Technology Center,
	IBM Software Labs
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux