Date: Thu, 8 Jan 2015 11:28:42 -0800 From: Adrian Chadd <adrian@freebsd.org> To: =?UTF-8?Q?Ermal_Lu=C3=A7i?= <eri@freebsd.org> Cc: Craig Rodrigues <rodrigc@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, Nikos Vassiliadis <nvass@gmx.com>, Gleb Smirnoff <glebius@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> Subject: Re: svn commit: r276747 - head/sys/netpfil/pf Message-ID: <CAJ-VmokvXJGmWc9bqsJrKcwvryqb4zH_8iwvrLBoEFaSsERi1g@mail.gmail.com> In-Reply-To: <CAPBZQG0Mq5T5NsGoJLmc8aDae6zyvtGwByWW6bQzrrzp8jg=jw@mail.gmail.com> References: <201501060903.t06934qp081875@svn.freebsd.org> <20150107204631.GG15484@FreeBSD.org> <AEFC5AEF-7700-426A-96D3-A14BF68CA9BC@lists.zabbadoz.net> <CAPBZQG0Mq5T5NsGoJLmc8aDae6zyvtGwByWW6bQzrrzp8jg=jw@mail.gmail.com>
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On 8 January 2015 at 00:13, Ermal Lu=C3=A7i <eri@freebsd.org> wrote: > > > On Thu, Jan 8, 2015 at 1:21 AM, Bjoern A. Zeeb > <bzeeb-lists@lists.zabbadoz.net> wrote: >> >> >> > On 07 Jan 2015, at 20:46 , Gleb Smirnoff <glebius@freebsd.org> wrote: >> > >> > On Tue, Jan 06, 2015 at 09:03:04AM +0000, Craig Rodrigues wrote: >> > C> Author: rodrigc >> > C> Date: Tue Jan 6 09:03:03 2015 >> > C> New Revision: 276747 >> > C> URL: https://svnweb.freebsd.org/changeset/base/276747 >> > C> >> > C> Log: >> > C> Instead of creating a purge thread for every vnet, create >> > C> a single purge thread and clean up all vnets from this thread. >> > C> >> > C> PR: 194515 >> > C> Differential Revision: D1315 >> > C> Submitted by: Nikos Vassiliadis <nvass@gmx.com> >> > >> > I am not sure that this is a good idea. The core idea of VNETs >> > is that they are isolated from each other. If we serialize purging, >> > then vnets are strongly affecting each other. >> > >> > AFAIU, from the PR there is some panic fixed. What is the actual bug >> > and why couldn't it be fixed with having per-vnet thread? >> >> You don=E2=80=99t 30000 whatever pf purging threads on a system all runn= ing, >> possibly competing for some resources, e.g., locks? > > > You can tune your system to your load! > > I do not agree with this change as well but just saw it! > > I would have agreed with this if a thread per CPU is created and some > improvements in the locking strategy is performed! > This is a potential issue since on busy system this thread gets very > resource consuming! So the tricksy bit here is once you have things being called via a taskqueue, they're effectively cooperative multitasking bits. A lot of things I've found aren't .. really designed for this. So I'm all for it, and I think it's a good idea in general, but then the pieces need to be reviewed for their suitability for this and may need some reworking so they don't hog CPU. (Yes, it's like writing WIN16 or MACOS code, or maybe network drivers in FreeBSD, but you get the idea.) -adrian
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