Date: Mon, 6 Jul 2009 18:43:42 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/amd64/amd64 pmap.c Message-ID: <200907061843.n66Ihr93098760@repoman.freebsd.org>
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alc 2009-07-06 18:43:42 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 pmap.c
Log:
SVN rev 195416 on 2009-07-06 18:43:42Z by alc
When pmap_change_attr() changes the PAT setting on a kernel mapping, it has
to simultaneously change the PAT setting for the same pages within the
direct map region. This may require the demotion of a 2MB page mapping and
the allocation of a page table page. This revision gives the highest
possible priority (VM_ALLOC_INTERRUPT) to this page allocation, so that
pmap_change_attr() is less likely to fail. (In general, kernel page table
page allocations have the highest priority, so this is not creating a new
precedent.)
(Demotion of 1GB page mappings within the direct map already specifies
VM_ALLOC_INTERRUPT to vm_page_alloc(), so only pmap_demote_pde() must be
changed.)
Approved by: re (kib)
Revision Changes Path
1.662 +11 -3 src/sys/amd64/amd64/pmap.c
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