set improves performance and fixes the following problems (description
from John Dyson):
1. Growing swap space problem in both static usage and
in situations with lots of fork/execs in heavy paging
situations.
2. Sparse swap space allocation (internal fragmentation.)
3. General swap_pager slowness.
Additionally, the new swap_pager also provides hooks for multi-page
I/O that is currently being developed (in early testing phases.)
Problem #1 is a result of a problem where objects cannot be collapsed
once a pager has been allocated for them. This problem has been solved
by relaxing the restriction by allowing the pages contained in a shadow
object's pager be copied to the parent object's pager. The copy is
afforded by manipulating pointers to the disk blocks on the swap space.
Since an improved swap_pager has already been developed with the data
structures to support the copy operation, this new swap_pager has been
introduced. Also, shadow object bypass in the collapse code has been
enhanced to support checking for pages on disk. The vm_pageout daemon
has also been modified to defer creation of an object's pager when the
object's shadow is paging. This allows efficient immediate collapsing
of a shadow into a parent object under many circumstances without the
creation of an intermediate pager.
Problem #2 is solved by the allocation data structures and algorithms
in the new swap_pager. Additionally, a newer version of this new swap_pager
is being tested that permits multiple page I/O and mitigation of the
fragmentation problems associated with allocation of large contiguous blocks
of swap space.
Problem #3 is addressed by better algorithms and a fix of a couple of bugs
in the swap_pager. Additionally, this new pager has a growth path allowing
multi-page inputs from disk. Approximately 50% performance improvement can
be expected under certain circumstances when using this pager in the standard
single page mode.
(Actually, I've seen more like twice the speed in my tests. -DLG)
are used or not.
Add .verions to the CLEANFILES+= on those Makefiles that create a version.c
file.
Remove reference to nonexistent file ref_omega.c in one Makefile.
Fix copy of authdes.c.expot so that it works with or without obj directories.
No compiles both with and without obj directories.
can actually write a sane netif device to support one of these. Note that it
was necessary to steal a netisr bit from another protocol; I took the one for
PF_DATAKIT (no great loss).
