Date: Wed, 17 Jun 2009 21:03:18 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: jroberson@jroberson.net Cc: arch@FreeBSD.org, grehan@FreeBSD.org, marius@alchemy.franken.de Subject: Re: Dynamic pcpu, arm, mips, powerpc, sun, etc. help needed Message-ID: <20090617.210318.1878034641.imp@bsdimp.com> In-Reply-To: <alpine.BSF.2.00.0906171231540.1025@desktop> References: <20090609201127.GA50903@alchemy.franken.de> <4A2F1148.9090706@freebsd.org> <alpine.BSF.2.00.0906171231540.1025@desktop>
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In message: <alpine.BSF.2.00.0906171231540.1025@desktop>
Jeff Roberson <jroberson@jroberson.net> writes:
:
: On Tue, 9 Jun 2009, Peter Grehan wrote:
:
: >> As for sparc64 allocating the storage for the dynamic area
: >> from end probably isn't a good idea as the pmap code assumes
: >> that the range from KERNBASE to end is covered by the pages
: >> allocated by and locked into the TLB for the kernel by the
: >> loader
: >
: > Ditto for ppc. It's possible to get the additional space from within or
: > after return from pmap_bootstrap() (like thread0's kstack, or the msgbuf).
:
: http://people.freebsd.org/~jeff/dpcpu.diff
:
: I have updated this patch based on feedback relating to various
: architectures md code. I tried to model most architectures after the way
: msgbuf memory was taken. I have no capacity to test anything other than
: i386 and amd64. ARM is reported to work with one minor diff. Apparently
: sparc64 worked with the earlier diff but this should be cleaner. If
: anyone can report back on sparc64, mips, or powerpc, I'd appreciate it.
I don't understand this part of the patch:
Index: mips/mips/mp_machdep.c
===================================================================
--- mips/mips/mp_machdep.c (revision 194275)
+++ mips/mips/mp_machdep.c (working copy)
@@ -224,12 +224,15 @@ static int
smp_start_secondary(int cpuid)
{
struct pcpu *pcpu;
+ void *dpcpu;
int i;
if (bootverbose)
printf("smp_start_secondary: starting cpu %d\n", cpuid);
+ dpcpu = (void *)kmem_alloc(kernel_map, DPCPU_SIZE);
pcpu_init(&__pcpu[cpuid], cpuid, sizeof(struct pcpu));
+ dpcpu_init(dpcpu, cpuid);
if (bootverbose)
printf("smp_start_secondary: cpu %d started\n", cpuid);
So were adding a dynamic per-cpu area, in addition to the fixed part?
Warner
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