Date: Wed, 28 Jul 2010 23:05:19 -1000 (HST) From: Jeff Roberson <jroberson@jroberson.net> To: Alan Cox <alc@cs.rice.edu> Cc: svn-src-projects@freebsd.org, Jeff Roberson <jeff@FreeBSD.org>, src-committers@freebsd.org Subject: Re: svn commit: r210586 - projects/ofed/head/sys/ofed/include/linux Message-ID: <alpine.BSF.2.00.1007282303220.1414@desktop> In-Reply-To: <4C50FB4A.4000505@cs.rice.edu> References: <201007290212.o6T2CN20099343@svn.freebsd.org> <4C50FB4A.4000505@cs.rice.edu>
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On Wed, 28 Jul 2010, Alan Cox wrote: > Jeff Roberson wrote: >> Author: jeff >> Date: Thu Jul 29 02:12:22 2010 >> New Revision: 210586 >> URL: http://svn.freebsd.org/changeset/base/210586 >> >> Log: >> - Refine various page allocation methods. They all essentially override >> the page object pointer to cache the virtual address after allocation. >> This same trick is used in UMA to store the slab address and so it >> should be safe. >> > > You needn't do this. The virtual address of a kernel_object or kmem_object > page is easily obtained: > > VM_MIN_KERNEL_ADDRESS + IDX_TO_OFF(m->pindex) Ah, of course. I hadn't considered that. Thanks. I'll remove the other hackery. On another note; linux guarantees multipage allocations are aligned on the first power of two size that satisfies the allocation. I can do this with contigmalloc but they also guarantee that the virtual address is similarly aligned. I don't think I've run across anything that requires it, but if I do, do we have any provision for allocating virtually aligned addresses? Thanks, Jeff > > > Regards, > Alan >
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