Date: Sat, 6 Sep 2014 15:37:10 -0700 From: Adrian Chadd <adrian@freebsd.org> To: Alan Cox <alc@rice.edu> Cc: Alan Cox <alc@freebsd.org>, Gleb Smirnoff <glebius@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: bug 193400: sfbuf changes on mips32 may have exposed some vm/pmap issues on mips32? Message-ID: <CAJ-Vmo=SuUif97Nm8KtiZ03f=e20TQczQeM3uVh%2B8PQkBbBeuw@mail.gmail.com> In-Reply-To: <540B8AA0.40005@rice.edu> References: <CAJ-Vmo=Y77btZq0iRxROACNj0WDzGrz0Dvx7FExhPOZVyRjKsg@mail.gmail.com> <540B8AA0.40005@rice.edu>
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On 6 September 2014 15:28, Alan Cox <alc@rice.edu> wrote: > On 09/06/2014 17:24, Adrian Chadd wrote: >> Hi! >> >> This bug: >> >> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=193400 >> >> is what I reported to alc a couple weeks ago as breaking on my 128mb >> RAM mipsbe board. >> >> It turns out that the difference between the MIPS32 sfbuf code and the >> new stuff gleb added was the refcounting side of things. With the MIPS >> code, there was no refcounting at all - each sfbuf allocation would >> allocate a new sfbuf. Now, I don't know how correct that is (my >> reading of the code is "not correct!") but it wasn't panicing things. >> >> So I think maybe gleb's patch to sfbuf exposed a MIPS32 pmap/VM bug? >> >> Alan - how would we go about figuring out what could be the issue here? > > I just sent you an email a few minutes ago describing how to restore the > old behavior. > Yup. I've also implemented the local sf_buf map and unmap routines; it seems to fix things. -a
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