Date: Tue, 18 Feb 2003 19:01:14 -0800 From: "Mooneer Salem" <mooneer@translator.cx> To: "FreeBSD Hackers" <freebsd-hackers@freebsd.org> Subject: RE: Per-jail CPU limits? Message-ID: <FHEMJMOKKMJDGKFOHHEPMEEBFAAA.mooneer@translator.cx> In-Reply-To: <FHEMJMOKKMJDGKFOHHEPKEDKFAAA.mooneer@translator.cx>
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Hello,
An update:
* I changed a block of code in kse_reassign() to the following:
if ((td = kg->kg_last_assigned)) {
do {
td = TAILQ_NEXT(td, td_runq);
} while (td && jail_check_cpu(td));
} else {
td = TAILQ_FIRST(&kg->kg_runq);
}
* jail_check_cpu() has been placed in kern_jail.c and looks like the
following:
int
jail_check_cpu(td)
struct thread *td;
{
struct prison *pr = td->td_ucred->cr_prison;
u_int totalcpu = td->td_ksegrp->kg_estcpu;
if (!pr) {
/* Not in jail; don't care about its CPU. */
return 0;
}
printf("cpu debug: %d\n", totalcpu);
/* By default, return 0. */
return 0;
}
jail_check_cpu() is a passthrough function that accepts by default and is
supposed
to print the total CPU used to the console. After recompiling the kernel and
rebooting,
I tried to start a jail. Unfortunately, I didn't see the message that should
have
been printed.
I believe kse_reassign() might only be called under certain circumstances
(e.g. when
SMP is involved). If that's the case, another function will need to be found
to
insert the code in.
Thanks,
--
Mooneer Salem
GPLTrans: http://www.translator.cx/
lifeafterking.org: http://www.lifeafterking.org/
-----Original Message-----
From: owner-freebsd-hackers@FreeBSD.ORG
[mailto:owner-freebsd-hackers@FreeBSD.ORG]On Behalf Of Mooneer Salem
Sent: Tuesday, February 18, 2003 5:07 PM
To: FreeBSD Hackers
Subject: Per-jail CPU limits?
Hello,
I've been looking at the kernel source, in particular the scheduler
in the past few weeks. I found a place in kern_switch.c where per-jail
CPU controls could be added (in particular, in the kse_reassign() function).
>From looking at that function, I could loop through td_runq until I either:
1. Found a thread that isn't jailed,
2. Found a jailed thread, but determine it's safe to let it run because
it does not go over sysctl-defined limits, or
3. Find no usable thread, in which case the KSE would theoretically switch
over to the idle process until it's time to repeat the process again.
This should allow the use of the standard FreeBSD scheduler, except for
the jail limits. The question is, how do we determine the total CPU used
by the jail? I found the kg_estcpu entry in struct ksegrp, which the thread
has a pointer to, but would that be enough? Is there a different approach we
could take that would solve this problem?
Thanks,
--
Mooneer Salem
GPLTrans: http://www.translator.cx/
lifeafterking.org: http://www.lifeafterking.org/
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