Date: Mon, 26 Jul 2010 13:27:14 +0530 From: "Jayachandran C." <c.jayachandran@gmail.com> To: Alan Cox <alc@cs.rice.edu> Cc: mips@freebsd.org Subject: Re: svn commit: r210460 - head/sys/mips/include Message-ID: <AANLkTikdC6PkiffMUXqhPWw9WkTLNZ5FsbJ7=6170%2Bzx@mail.gmail.com> In-Reply-To: <4C4D3AC1.8080201@cs.rice.edu> References: <201007250419.o6P4J50q033283@svn.freebsd.org> <4C4BC213.5060001@cs.rice.edu> <AANLkTik%2BBV6u6fNVX8Ntb-G1yF=vEDh6VqB7Xcb5VtD-@mail.gmail.com> <20100725.052629.160100930644600654.imp@bsdimp.com> <4C4D3AC1.8080201@cs.rice.edu>
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On Mon, Jul 26, 2010 at 1:05 PM, Alan Cox <alc@cs.rice.edu> wrote: > M. Warner Losh wrote: >> >> In message: <AANLkTik+BV6u6fNVX8Ntb-G1yF=3DvEDh6VqB7Xcb5VtD-@mail.gmail.= com> >> =A0 =A0 =A0 =A0 =A0 =A0"Jayachandran C." <c.jayachandran@gmail.com> writ= es: >> : 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: >> : >> =A0Get N64 building by defining VM_FREELIST_DIRECT to be >> : >> =A0VM_FREELIST_DEFAULT. =A0I believe this is correct, since KX is s= et in >> : >> =A0n64, 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. =A0Any 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(). =A0There may, however, be s= ome > point to using VM_WAIT in pmap_grow_pte_page_cache(), because > vm_contig_grow_cache() is far more aggressive about paging out dirty page= s > than VM_WAIT is, and VM_WAIT would suffice. Thanks - the 64 bit is the HEAD is still in early development, so I was just trying to understand this better. > For what it's worth, fixing pmap_change_wiring() and > pmap_page_wired_mappings() is almost certainly more important. I had seen the mail on this, but thought I will look at this after the 64 bit support work (if it is not fixed by then). JC.
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