On 02/07/2012 06:15 AM, Serge Hallyn wrote:
Quoting atp (Andrew.Phillips@xxxxxxxx):
Hello,
Apologies if I'm about to ask a frequently asked question - I did
check back over the last couple of months.
Is anyone working on cpu shielding for processes inside a cpu cgroup?
We would like to run Java in containers, and unfortunately it likes to
know how many processors there are in the system - to initialise thread
pools and such like.
I was thinking along these lines;
--- fs/proc/stat.c.orig 2010-05-21 11:32:32.941258466 +0000
+++ fs/proc/stat.c 2010-05-21 11:40:47.681259133 +0000
@@ -39,7 +39,9 @@
getboottime(&boottime);
jif = boottime.tv_sec;
- for_each_possible_cpu(i) {
+// for_each_possible_cpu(i) {
+// // refer to the visible cpus.
+ for_each_cpu_and(i,cpu_possible_mask,(¤t->cpus_allowed)) {
user = cputime64_add(user, kstat_cpu(i).cpustat.user);
nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);
system = cputime64_add(system, kstat_cpu(i).cpustat.system);
@@ -78,7 +80,10 @@
(unsigned long long)cputime64_to_clock_t(steal),
(unsigned long long)cputime64_to_clock_t(guest),
(unsigned long long)cputime64_to_clock_t(guest_nice));
- for_each_online_cpu(i) {
+
+// for_each_online_cpu(i) {
+// // cgroup.
+ for_each_cpu_and(i,cpu_online_mask,(¤t->cpus_allowed)) {
/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
user = kstat_cpu(i).cpustat.user;
I'm sure that there are nicer ways of doing this, but Serge Hallyn
suggested a while ago that I post here. Even though it says 2010, the
patch above looks like it will go against 3.2.4 ok.
Thanks,
Andy
I'm afraid I haven't been following recent upstream discussions on
this, but there are other people who want proc to show cgroup-limited
information. See for instance http://lwn.net/Articles/460310/ . Glauber
has also brought this up since then. I'd recommend pinging him.
I'm all for /proc showing cgroup-filtered information, unconditionally.
Hi.
I have a patchset pending for review that deals with some part of that.
(http://lwn.net/Articles/479624/)
The way I see it, there are two parts of the problem: One of them is
keeping all those information consistently in the cgroup. I don't really
like your patch, btw, because it takes the process as the main entity,
and that is not really proc's idea. I'd go to the route of trying to
devise a cpumask from the cgroup, and then expose this. That said, I
believe anything in this area is far from a consensus.
Another problem is how to effectively display such data, after you
gathered it. I am not essentially opposed to unconditionally displaying
cgroup-filtered data as well, and I've sent a couple of patches trying
to achieve that. But there are some problems with this approach that are
preventing consensus now.
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