Date: Sun, 26 Jan 2014 08:04:48 -0800 From: Juli Mallett <jmallett@FreeBSD.org> To: Jan Bramkamp <crest@rlwinm.de> Cc: "freebsd-mips@FreeBSD.org" <freebsd-mips@freebsd.org> Subject: Re: More trapframe panics Message-ID: <CACVs6=-_N8aPEeFT5P8aTr1hkpmBWGwCt930wsGzg4YHxr8VKg@mail.gmail.com> In-Reply-To: <52E524BD.7090106@rlwinm.de> References: <52E42A1B.3040907@rewt.org.uk> <CACVs6=--Qy_8poWdHdCXYKqkO22=dvHhW8=Uma8kLR%2BhCoZDxw@mail.gmail.com> <52E524BD.7090106@rlwinm.de>
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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. Thanks, Juli.
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