Date: Sun, 21 Jun 2009 14:09:54 -1000 (HST) From: Jeff Roberson <jroberson@jroberson.net> To: Marius Strobl <marius@alchemy.franken.de> Cc: arch@freebsd.org, Peter Grehan <grehan@freebsd.org> Subject: Re: Dynamic pcpu, arm, mips, powerpc, sun, etc. help needed Message-ID: <alpine.BSF.2.00.0906211406300.998@desktop> In-Reply-To: <20090621140312.GC71667@alchemy.franken.de> References: <alpine.BSF.2.00.0906032050220.981@desktop> <20090609201127.GA50903@alchemy.franken.de> <4A2F1148.9090706@freebsd.org> <alpine.BSF.2.00.0906171231540.1025@desktop> <20090621140312.GC71667@alchemy.franken.de>
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On Sun, 21 Jun 2009, Marius Strobl wrote: > On Wed, Jun 17, 2009 at 12:55:52PM -1000, Jeff Roberson wrote: >> >> 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. >> > > The earlier patch worked on sparc64 as long as the kernel > happened to leave enough room in the last 4MB page allocated > for it. > The new version unfortunately doesn't compile on sparc64 as > pmap_bootstrap_alloc() is static to its pmap.c (I think it > should also stay that way). Also the memory allocated with > it isn't safe to be used before we've taken over the trap > table. A kernel built with the sparc64 bits replaced with > the following patch boots fine: > http://people.freebsd.org/~marius/sparc64_dpcpu.diff > Do you have some simple test case for DPCPU which can be > used to verify that it actually works? Thanks very much Marius. I have updated the patch at: http://people.freebsd.org/~jeff/dpcpu.diff I intend to commit this, minus the kern_synch.c diff tomorrow. There was an id in the previous patch that caused each area to be accessed as it was added but you'd have to have done a 'show pcpu' in ddb after boot to access the area. I added a counter in kern_synch.c as a better test. new in this diff: 1) I made each access cheaper by one instruction by making the pc_dynamic pointer relative to the start of the percpu area. 2) I added two helper functions for sysctl ints and quads that can be used for stats. See the temporary kern_synch.c diff for an example. 3) sparc64/sun4v by marius 4) ia64 fixes suggested by marcel. Thanks, Jeff > > Marius >
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