14.12.2017 23:00, Konstantin Belousov wrote: >>>>> Sigh. This would make i386 even less usable for everybody, perhaps >>>>> except you. Because default 3G of UVA is too small for some common tasks >>>>> (thanks clang, but also e.g. pypy), and you reduce the user address >>>>> space even more. >>>> Those who need 3GB of UVA within single process should not use 32 bit >>>> system in first place, should they? >>> Why do you even consider it acceptable to break the configuration just >>> because you are not interested in the workload ? >> I do not consider it is acceptable. I'm trying to find compromise. > If you do not find the proposed change acceptable, why do you propose > it at all ?
I do not consider breakage acceptable but not the change. I am still in doubt and that's why I'm asking questions. I doubt, how average i386 workstation or server can generate 1000+ threads and what is real threshold to get problems because of KVA fragmentation? >>> 386 arch configuration is not perfect but it provides the main intended >>> service of general-purpose workstation, with some limitation caused by >>> 32bit of address space being somewhat low for modern code. Appliance >>> flavoring of the default 386 config is unacceptable. Keep your tweaks >>> local. >> >> Do you think that kstack overflow of general-purpose workstation using NFS >> or IPv6 or WiFi with SCTP is OK? I do not. > > Kernel stack overflow is not 'OK', but two things are equally troublesome: > - papering over the problem of large structures allocated on stack by > increasing the stack size; > - ignoring the explanation why the stack increase is problematic by itself The change was submitted for discussion before any kind of explanation was given. > and generating thread consisting of 50+ content-less messages claiming > that 'it fixes the problem for me'. Not for "me". For average i386 user of IPv6 or SCTP or NFS etc. reporting double faults. > The proper route to fix the issues was already explained more than > several times, and you (and I, and other people) participated in the > ongoing efforts there. If it is so much important to you, wave the flag > and herd the action, by asking relevant people to help with fixes, be it > writing the patches, providing reviews or just finding the place where > the stack is abused. It requires identification and time to think and > develop specific changes for each place, and cannot happen in one day. Exactly. The problem is officialy noted in our docs since 10.2-RELEASE at least. And I doubt we can fix all the code in some foreseeable future and 11.2-RELEASE will still panic same way. And 12.0-RELEASE too, I'm afraid. And that is more important than keeping old defaults for i386 workstation users *unless* there are really lots of applications creating large number of threads/subprocesses. > But it also would not break KVA-starved architectures and provide fixes > relevant to even KVA-ample machines, as you other example shown. > > For the case of extreme use, there is still the tunable (and ZFS on i386 > is extreme). Sadly, we have too many "extreme" cases, as user reports and code analisys shows. That's the problem. _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
