Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hello, On 15.6.2018 г. 22:07 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 08:40:02PM +0300, Ivan Zahariev wrote: The lazy pids accounting + modern fast CPUs makes the "pids.current" metric practically unusable for resource limiting in our case. For a test, when we started and ended one single

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hello, On 15.6.2018 г. 22:07 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 08:40:02PM +0300, Ivan Zahariev wrote: The lazy pids accounting + modern fast CPUs makes the "pids.current" metric practically unusable for resource limiting in our case. For a test, when we started and ended one single

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, Ivan. On Fri, Jun 15, 2018 at 08:40:02PM +0300, Ivan Zahariev wrote: > The lazy pids accounting + modern fast CPUs makes the "pids.current" > metric practically unusable for resource limiting in our case. For a > test, when we started and ended one single process very quickly, we > saw

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, Ivan. On Fri, Jun 15, 2018 at 08:40:02PM +0300, Ivan Zahariev wrote: > The lazy pids accounting + modern fast CPUs makes the "pids.current" > metric practically unusable for resource limiting in our case. For a > test, when we started and ended one single process very quickly, we > saw

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hello, On 15.6.2018 г. 19:16 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 07:07:27PM +0300, Ivan Zahariev wrote: I understand all concerns and design decisions. However, having RLIMIT_NPROC support combined with "cgroups" hierarchy would be very handy. Does it make sense that you introduce

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hello, On 15.6.2018 г. 19:16 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 07:07:27PM +0300, Ivan Zahariev wrote: I understand all concerns and design decisions. However, having RLIMIT_NPROC support combined with "cgroups" hierarchy would be very handy. Does it make sense that you introduce

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, On Fri, Jun 15, 2018 at 07:07:27PM +0300, Ivan Zahariev wrote: > I understand all concerns and design decisions. However, having > RLIMIT_NPROC support combined with "cgroups" hierarchy would be very > handy. > > Does it make sense that you introduce "nproc.current" and > "nproc.max"

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, On Fri, Jun 15, 2018 at 07:07:27PM +0300, Ivan Zahariev wrote: > I understand all concerns and design decisions. However, having > RLIMIT_NPROC support combined with "cgroups" hierarchy would be very > handy. > > Does it make sense that you introduce "nproc.current" and > "nproc.max"

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hi, Thank you for the quick and insightful reply. I have one suggestion below: On 15.6.2018 г. 18:41 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 05:26:04PM +0300, Ivan Zahariev wrote: The standard RLIMIT_NPROC does not suffer from such accounting discrepancies at any time. They seem

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
Hi, Thank you for the quick and insightful reply. I have one suggestion below: On 15.6.2018 г. 18:41 ч., Tejun Heo wrote: On Fri, Jun 15, 2018 at 05:26:04PM +0300, Ivan Zahariev wrote: The standard RLIMIT_NPROC does not suffer from such accounting discrepancies at any time. They seem

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, On Fri, Jun 15, 2018 at 05:26:04PM +0300, Ivan Zahariev wrote: > The standard RLIMIT_NPROC does not suffer from such accounting > discrepancies at any time. RLIMIT_NPROC uses a dedicated atomic counter which is updated when the process is getting reaped; however, that doesn't actually

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Tejun Heo
Hello, On Fri, Jun 15, 2018 at 05:26:04PM +0300, Ivan Zahariev wrote: > The standard RLIMIT_NPROC does not suffer from such accounting > discrepancies at any time. RLIMIT_NPROC uses a dedicated atomic counter which is updated when the process is getting reaped; however, that doesn't actually

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
On 14.6.2018 г. 18:06 ч., Tejun Heo wrote: On Thu, Jun 14, 2018 at 02:56:00PM +0300, Ivan Zahariev wrote: I posted a kernel bug about this a month ago but it did not receive any attention: https://bugzilla.kernel.org/show_bug.cgi?id=199713 Here is a copy of the bug report and I hope that this

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-15 Thread Ivan Zahariev
On 14.6.2018 г. 18:06 ч., Tejun Heo wrote: On Thu, Jun 14, 2018 at 02:56:00PM +0300, Ivan Zahariev wrote: I posted a kernel bug about this a month ago but it did not receive any attention: https://bugzilla.kernel.org/show_bug.cgi?id=199713 Here is a copy of the bug report and I hope that this

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-14 Thread Aleksa Sarai
On 2018-06-15, Aleksa Sarai wrote: > > I've tested this on 4.14.27 and 4.4.0-124-generic Ubuntu. > > > > If I start a couple of processes which exit very quickly (like a simple Bash > > script with many commands in it), the reported value in "pids.current" is > > not updated immediately when

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-14 Thread Aleksa Sarai
On 2018-06-15, Aleksa Sarai wrote: > > I've tested this on 4.14.27 and 4.4.0-124-generic Ubuntu. > > > > If I start a couple of processes which exit very quickly (like a simple Bash > > script with many commands in it), the reported value in "pids.current" is > > not updated immediately when

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-14 Thread Aleksa Sarai
On 2018-06-14, Ivan Zahariev wrote: > I posted a kernel bug about this a month ago but it did not receive any > attention: https://bugzilla.kernel.org/show_bug.cgi?id=199713 I believe that very few people watch the kernel bugzilla -- it's almost always better to send a mail to LKML (speaking of

Re: Cgroups "pids" controller does not update "pids.current" count immediately

2018-06-14 Thread Aleksa Sarai
On 2018-06-14, Ivan Zahariev wrote: > I posted a kernel bug about this a month ago but it did not receive any > attention: https://bugzilla.kernel.org/show_bug.cgi?id=199713 I believe that very few people watch the kernel bugzilla -- it's almost always better to send a mail to LKML (speaking of