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mirror of https://git.FreeBSD.org/src.git synced 2025-01-01 12:19:28 +00:00
freebsd/sys/amd64
Alan Cox 0d2e1c3e39 Clearing a page table entry's accessed bit (PG_A) and setting the
page's PG_REFERENCED flag in pmap_protect() can't really be justified.
In contrast to pmap_remove() or pmap_remove_all(), the mapping is not
being destroyed, so the notion that the page was accessed is not lost.
Moreover, clearing the page table entry's accessed bit and setting the
page's PG_REFERENCED flag can throw off the page daemon's activity
count calculation.  Finally, in my tests, I found that 15% of the
atomic memory operations being performed by pmap_protect() were only
to clear PG_A, and not change protection.  This could, by itself, be
fixed, but I don't see the point given the above argument.

Remove a comment from pmap_protect_pde() that is no longer meaningful
after the above change.
2010-04-25 20:40:45 +00:00
..
acpica Use the same policy for rejecting / not-reject ACPI tables with incorrect 2010-03-19 12:43:18 +00:00
amd64 Clearing a page table entry's accessed bit (PG_A) and setting the 2010-04-25 20:40:45 +00:00
compile
conf Change USB_DEBUG to #ifdef and allow it to be turned off. Previously this had 2010-04-22 21:31:34 +00:00
ia32 As was done in r155238 for i386 and in r155239 for amd64, clear the carry 2010-04-21 11:17:16 +00:00
include Move the constants specifying the size of struct kinfo_proc into 2010-04-24 12:49:52 +00:00
linux32 Rename st_*timespec fields to st_*tim for POSIX 2008 compliance. 2010-03-28 13:13:22 +00:00
pci number of cleanups in i386 and amd64 pci md code 2009-09-24 07:11:23 +00:00
Makefile Adjustments to make a tags file a bit more suitable to amd64. 2008-12-01 14:15:10 +00:00