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author | alc <alc@FreeBSD.org> | 2009-07-18 01:50:05 +0000 |
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committer | alc <alc@FreeBSD.org> | 2009-07-18 01:50:05 +0000 |
commit | 40432bac3b537e4cec296ffff5f03ccc6e206725 (patch) | |
tree | 3735260e5ee08da379a2641b39b41827e7347d4d /sys/i386 | |
parent | 524e45ea991626d48d957b1617e055ac1daa1a75 (diff) | |
download | FreeBSD-src-40432bac3b537e4cec296ffff5f03ccc6e206725.zip FreeBSD-src-40432bac3b537e4cec296ffff5f03ccc6e206725.tar.gz |
An addendum to r195649, "Add support to the virtual memory system for
configuring machine-dependent memory attributes...":
Don't set the memory attribute for a "real" page that is allocated to
a device object in vm_page_alloc(). It is a pointless act, because
the device pager replaces this "real" page with a "fake" page and sets
the memory attribute on that "fake" page.
Eliminate pointless code from pmap_cache_bits() on amd64.
Employ the "Self Snoop" feature supported by some x86 processors to
avoid cache flushes in the pmap.
Approved by: re (kib)
Diffstat (limited to 'sys/i386')
-rw-r--r-- | sys/i386/i386/pmap.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c index adcbd83..6103fd5 100644 --- a/sys/i386/i386/pmap.c +++ b/sys/i386/i386/pmap.c @@ -4420,7 +4420,9 @@ pmap_mapdev_attr(vm_paddr_t pa, vm_size_t size, int mode) pa += PAGE_SIZE; } pmap_invalidate_range(kernel_pmap, va, tmpva); - pmap_invalidate_cache(); + /* If "Self Snoop" is supported, do nothing. */ + if (!(cpu_feature & CPUID_SS)) + pmap_invalidate_cache(); return ((void *)(va + offset)); } @@ -4467,7 +4469,9 @@ pmap_page_set_memattr(vm_page_t m, vm_memattr_t ma) * Flush CPU caches to make sure any data isn't cached that shouldn't * be, etc. */ - pmap_invalidate_cache(); + /* If "Self Snoop" is supported, do nothing. */ + if (!(cpu_feature & CPUID_SS)) + pmap_invalidate_cache(); } int @@ -4526,7 +4530,9 @@ pmap_change_attr(vm_offset_t va, vm_size_t size, int mode) * be, etc. */ pmap_invalidate_range(kernel_pmap, base, tmpva); - pmap_invalidate_cache(); + /* If "Self Snoop" is supported, do nothing. */ + if (!(cpu_feature & CPUID_SS)) + pmap_invalidate_cache(); return (0); } |