Date: Mon, 27 Jan 2014 01:04:46 +0000 From: Joe Holden <lists@rewt.org.uk> To: freebsd-mips@freebsd.org Subject: Re: More trapframe panics Message-ID: <52E5B0AE.7030106@rewt.org.uk> In-Reply-To: <453F8F8F-41E5-4640-9683-5A8553AB0822@bsdimp.com> References: <52E42A1B.3040907@rewt.org.uk> <CACVs6=--Qy_8poWdHdCXYKqkO22=dvHhW8=Uma8kLR%2BhCoZDxw@mail.gmail.com> <52E524BD.7090106@rlwinm.de> <CACVs6=-_N8aPEeFT5P8aTr1hkpmBWGwCt930wsGzg4YHxr8VKg@mail.gmail.com> <453F8F8F-41E5-4640-9683-5A8553AB0822@bsdimp.com>
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On 26/01/2014 18:54, Warner Losh wrote: > > On Jan 26, 2014, at 9:04 AM, Juli Mallett wrote: > >> On Sun, Jan 26, 2014 at 7:07 AM, Jan Bramkamp <crest@rlwinm.de> wrote: >>> >>> Would increasing KSTACK_PAGES from two to three or four help? What are >>> the trade-offs involved in choosing KSTACK_PAGES for something like the >>> EdgeMax Lite? >> >> >> That's exactly what needs to happen in all 64-bit MIPS kernels. Unlike >> some other architectures, KSTACK_PAGES cannot simply be increased, >> however. All of the code which handles loading the kernel stack and >> keeping it mapped, etc., assumes that it takes up exactly one TLB entry, >> i.e. 2 pages. One could simply double KSTACK_PAGES for 64-bit builds and >> modify the code to support the case of 2 or 4 pages, which would keep the >> code as gross as it is today and not buy much flexibility, but might be >> worthwhile as a short-term fix. Being able to support arbitrary values of >> KSTACK_PAGES (or at least arbitrary multiples of 2 up to the maximum number >> of wired TLB entries times 2) would be better. > > I hacked together a kludge that quadrupled this by going to the next larger page size for stack pages in the TLB, but hit something ugly when I did that... But I've lost that code, so maybe I should try again to see if I'm more clever the second time. > > This is one of the things that makes it hard to have a nice native build server on mips64... > > Warner > I have plenty of hardware (pretty much just spare ERLs) that you can use if you want - unless you can give me some ideas on other mips64 hardware that would be useful in which case I can make that available too.
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