Date: Mon, 26 Jul 2010 02:35:29 -0500 From: Alan Cox <alc@cs.rice.edu> To: "M. Warner Losh" <imp@bsdimp.com> Cc: mips@freebsd.org Subject: Re: svn commit: r210460 - head/sys/mips/include Message-ID: <4C4D3AC1.8080201@cs.rice.edu> In-Reply-To: <20100725.052629.160100930644600654.imp@bsdimp.com> References: <201007250419.o6P4J50q033283@svn.freebsd.org> <4C4BC213.5060001@cs.rice.edu> <AANLkTik%2BBV6u6fNVX8Ntb-G1yF=vEDh6VqB7Xcb5VtD-@mail.gmail.com> <20100725.052629.160100930644600654.imp@bsdimp.com>
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M. Warner Losh wrote: > In message: <AANLkTik+BV6u6fNVX8Ntb-G1yF=vEDh6VqB7Xcb5VtD-@mail.gmail.com> > "Jayachandran C." <c.jayachandran@gmail.com> writes: > : On Sun, Jul 25, 2010 at 10:18 AM, Alan Cox <alc@cs.rice.edu> wrote: > : > Warner Losh wrote: > : >> > : >> Author: imp > : >> Date: Sun Jul 25 04:19:05 2010 > : >> New Revision: 210460 > : >> URL: http://svn.freebsd.org/changeset/base/210460 > : >> > : >> Log: > : >> Get N64 building by defining VM_FREELIST_DIRECT to be > : >> VM_FREELIST_DEFAULT. I believe this is correct, since KX is set in > : >> n64, and thus all RAM can be direct mapped. > : > : Thanks, this is something I missed in my MIPS page table changes. > : > : > > : > Yes, it is. > : > : In MIPS 64bit, whole physical memory is direct mapped thru a XKPHYS > : region. We can use vm_page_alloc() for pmap_alloc_pte_page() and > : VM_WAIT for pmap_grow_pte_page_cache(), is this something we should > : consider? > > Likely. Any idea what kind of performance difference this would buy > us? > As long as n64 has a single free list, there is no point in changing pmap_alloc_pte_page() to use vm_page_alloc(). There may, however, be some point to using VM_WAIT in pmap_grow_pte_page_cache(), because vm_contig_grow_cache() is far more aggressive about paging out dirty pages than VM_WAIT is, and VM_WAIT would suffice. For what it's worth, fixing pmap_change_wiring() and pmap_page_wired_mappings() is almost certainly more important. Alan
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