1. The pageout daemon used to block under certain
circumstances, and we needed to add new functionality
that would cause the pageout daemon to block more often.
Now, the pageout daemon mostly just gets rid of pages
and kills processes when the system is out of swap.
The swapping, rss limiting and object cache trimming
have been folded into a new daemon called "vmdaemon".
This new daemon does things that need to be done for
the VM system, but can block. For example, if the
vmdaemon blocks for memory, the pageout daemon
can take care of it. If the pageout daemon had
blocked for memory, it was difficult to handle
the situation correctly (and in some cases, was
impossible).
2. The collapse problem has now been entirely fixed.
It now appears to be impossible to accumulate unnecessary
vm objects. The object collapsing now occurs when ref counts
drop to one (where it is more likely to be more simple anyway
because less pages would be out on disk.) The original
fixes were incomplete in that pathological circumstances
could still be contrived to cause uncontrolled growth
of swap. Also, the old code still, under steady state
conditions, used more swap space than necessary. When
using the new code, users will generally notice a
significant decrease in swap space usage, and theoretically,
the system should be leaving fewer unused pages around
competing for memory.
Submitted by: John Dyson
stages of debugging LFS:
* if we can't bmap, use old VOP code
*/
! if (/* (vp->v_mount && vp->v_mount->mnt_stat.f_type == MOUNT_LFS) || */
! VOP_BMAP(vp, foff, &dp, 0, 0)) {
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
--- 804,810 ----
/*
* if we can't bmap, use old VOP code
*/
! if (VOP_BMAP(vp, foff, &dp, 0, 0)) {
Reviewed by: gibbs
Submitted by: John Dyson
Disable the bogus declaration of pmap_bootstrap(). Since its arg list
is machine-dependent, it must be declared in a machine-dependent header.
vm_page.h:
Change `inline' to `__inline' and old-style function parameter lists for
inlined functions to new-style.
`inline' and old-style function parameter lists should never be used in
system headers, even in very machine-dependent ones, because they cause
warnings from gcc -Wreally-all.
fault was at offset 0 in the object. This resulted in more overhead but
was othewise benign. Added incore() check in vnode_pager_has_page()
to work around a problem with LFS...other than slightly higher overhead,
this change has no affect on UFS.
Enabled via REL2_1.
Added support for doing object collapses "on the fly". Enabled via REL2_1a.
Improved object collapses so that they can happen in more cases. Improved
sensing of modified pages to fix an apparant race condition and improve
clustered pageout opportunities. Fixed an "oops" with not restarting page
scan after a potential block in vm_pageout_clean() (not doing this can result
in strange behavior in some cases).
Submitted by: John Dyson & David Greenman
that this is intended for use only in floppy situations and is done at
the sacrifice of performance in that case (in ther words, this is not the
best solution, but works okay for this exceptional situation).
Submitted by: John Dyson
From now on, >all< swapdevices must be activated with "swapon".
If you havn't got it, add this line to /etc/fstab:
/dev/wd0b none swap sw 0 0
ne sec
Reason:
We want our GENERIC* kernels to have a large selection of swap-devices, but
on the other hand, we don't want to use a wd0b as swap when we boot of a
floppy. This way, we will never use a unexpected swapdevice. Nothing else
has changed.
scheme of things, so I've changed them to be more appropriate. page in/ous
are now associated with the pager that did them. Nuked v_fault as the
only fault of interest that wouldn't be already counted in v_trap is a VM
fault, and this is counted seperately.
2) Implemented most of the remaining counters and corrected the counting of
some that were done wrong. They are all almost correct now...just a few
minor ones left to fix.
inadvertantly introduced in pre-1.1.5. This could cause page modifications
to go unnoticed during certain extreme low memory/high paging rate conditions.
Submitted by: John Dyson and David Greenman
