Date: Wed, 4 Sep 2013 12:00:55 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: freebsd-geom@freebsd.org, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Alexander Motin <mav@freebsd.org>, Nathan Whitehorn <nwhitehorn@freebsd.org>, Outback Dingo <outbackdingo@gmail.com>, Olivier =?iso-8859-1?q?Cochard-Labb=E9?= <olivier@cochard.me>, FreeBSD SCSI <freebsd-scsi@freebsd.org> Subject: Re: [RFC][CFT] GEOM direct dispatch and fine-grained CAM locking Message-ID: <201309041200.56024.jhb@freebsd.org> In-Reply-To: <52273F90.7020303@freebsd.org> References: <520D4ADB.50209@FreeBSD.org> <CAFMmRNzkL%2BuOsC=2Cq_S4Zm5fkmrQRNYcKfijA8yyYcxvLaXPQ@mail.gmail.com> <52273F90.7020303@freebsd.org>
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On Wednesday, September 04, 2013 10:11:28 am Nathan Whitehorn wrote: > On 09/04/13 08:20, Ryan Stone wrote: > > On Wed, Sep 4, 2013 at 8:45 AM, Nathan Whitehorn <nwhitehorn@freebsd.org> wrote: > >> Could you describe what this macro is supposed to do so that we can do the > >> porting work? > >> -Nathan > > #define GET_STACK_USAGE(total, used) > > > > GET_STACK_USAGE sets the variable passed in total to the total amount > > of stack space available to the current thread. used is set to the > > amount of stack space currently used (this does not have to have > > byte-precision). Netgraph uses this to decide when to stop recursing > > and instead defer to a work queue (to prevent stack overflow). I > > presume that Alexander is using it in a similar way. It looks like > > the amd64 version could be ported to other architectures quite easily > > if you were to account for stacks that grow up and stacks that grow > > down: > > > > http://svnweb.freebsd.org/base/head/sys/amd64/include/proc.h?revision=233291&view=markup > > > > /* Get the current kernel thread stack usage. */ > > #define GET_STACK_USAGE(total, used) do { \ > > struct thread *td = curthread; \ > > (total) = td->td_kstack_pages * PAGE_SIZE; \ > > (used) = (char *)td->td_kstack + \ > > td->td_kstack_pages * PAGE_SIZE - \ > > (char *)&td; \ > > } while (0) > > _______________________________________________ > > freebsd-hackers@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > > I think that should be MI for us anyway. I'm not aware of any > architectures FreeBSD supports with stacks that grow up. I'll give it a > test on PPC. ia64 has the double stack thingie where the register stack spills into a stack that grows up rather than down. Not sure how sparc64 window spills are handled either. -- John Baldwin
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