In addition to current one (i.e., don't wast so large part of the page),
- if the header fitsin the page without wasting any items, put it there.
- don't put the header in the page if it may consume rather big item.
For example, on i386, header is now allocated in the page for the pools
like fdescpl or sigapl, and allocated off the page for the pools like
buf1k or buf2k.
kern.proc, kern.proc2, kern.lwp, and kern.buf.
Define more MIB for kern.buf so that specific buffers can be selected
(only all/all is supported right now), and use a 32/64 bit agnostic
structure for communcating buffer information to userland.
Convert systat to the new kern.buf method.
Clean up the vm.buf* handling a little. There's no actual need to
record the dynamically assigned OIDs, since sysctl_data can tell us
what we're looking at.
Oh, and fix a typo in a comment.
and then allocate it on demand. Rename some common symbols (__bss_start,
_edata, _end, __start_link_set_*, __stop_link_set_*) so that ".<module>"
is appended to them. This shrinks an amd64 kernel by 20KB of BSS.
of using on-stack memory, so that this wouldn't eventually cause kernel
panic if the process get swapped out and another process runs kqueue_scan()
problem pointed out in kern/24220 by Stephan Uphoff
called with every buffer written through spec_strategy().
Used by fss(4). Future file-system-internal snapshots will need them too.
Welcome to 1.6ZK
Approved by: Jason R. Thorpe <thorpej@netbsd.org>
so the last change has us comparing pages to bytes instead of pages
to buffers! The consequence was to try to free radically less memory
than UVM wanted us to -- though always at least one buffer, which is
probably why the results weren't dire.
This does suggest that buf_canrelease() could be a *lot* more
conservative about how much to release than "2 * page deficit". In
fact, serious trouble seems to ensue if it's not -- when anything
else on the system demands enough pages, we slam down to the low
water mark nd stay there. I've adjusted it to use min(page defecit,
buffer memory / 16), which still isn't quite right but seems better.
Another change: consider the case of an infinite loop that does
"tar xzf pkgsrc.tar.gz ; rm -rf pkgsrc". Each time the rm runs,
all the dead metadata will go on the AGE list -- and, until we hit
the high-water mark, stay there, at which point it may be slowly
recycled. Two adjustments seem to solve this: 1) whack buf_lotsfree()
to return 0 if there's anything on the AGE list; 2) whack buf_canrelease()
to count the memory used by the AGE list and always return at least
that much.
This basically turns the AGE list into a "delayed free" list, since we
can't entirely eliminate it as we can't free pool items from interrupt
context (e.g. from biodone()).
To consider: with the bookkeeping corrected, should buf_drain() move
back to the _end_ of the pagedaemon, and should the calculation then
try to give back at least the current defecit?
the latter is not a appropriate place to do so and it broke vfork.
- deactivate pmap before calling cpu_exit() to keep a balance of
pmap_activate/deactivate.
and uncontrolled growth.
The key fix is from Dan Carasone, who noticed that buf_canfree() was
counting in _bytes_ but freeing in _buffers_, which caused the instant
drop to lowater observed by some users.
We now control the rate of growth; the probability of getting a new
allocation is inversely proportional to the current size of the
cache. This idea is from a long-ago conversation with Kirk McKusick
and, if memory serves, was used for the file-system cache in some
other BSD variant at some point in history.
With growth and shrinkage more or less dealt with, we return the
default maximum cache size to 15%. The default _minimum_ cache size
is raised from 1/16 of the maximum cache size to 1/8, since 1/16 was
chosen when the maximum size was 30% of memory.
Finally, after observing the behaviour of the pagedaemon and the
buffer cache drainer under pathological workloads (e.g. a benchmark
that steps through 75% of available memory backwards) I have moved
the call to buf_drain() to the beginning of the pagedaemon from the
end; if the pagedaemon bogs down, it still won't get run as often
as it should, but at least this way it will see the state of the
free count and free target _before_ the scan step does its thing.
PR#23470, with minor updates by me. This is only the syscall support
from that PR, for now.
Changes: port over fix from FreeBSD for multicast address generation.
Changed bcopy to memcpy. For now, #ifdef notyet the portions of
kern_uuid.c that are meant to be used by (currently nonexistent) other
things in the kernel. Added syscall to COMPAT_FREEBSD as well, though
that's currently not useful, as any program new enough to use this call
also uses other syscalls we don't (yet) emulate.
tripping over this getting too large, and suffering other performance
problems due to the lack of good backpressure shrinking the bufcache
when other memory is required. Again, this tunable should be
revisited when the backpressure mechanism has been improved.
sysctl vm.bufcache can be used to manually tune those rare machines
that might need more than this.
See comments in rev 1.106 for more detail.
VOP_STRATEGY(bp) is replaced by one of two new functions:
- VOP_STRATEGY(vp, bp) Call the strategy routine of vp for bp.
- DEV_STRATEGY(bp) Call the d_strategy routine of bp->b_dev for bp.
DEV_STRATEGY(bp) is used only for block-to-block device situations.
VOP_STRATEGY(bp) is replaced by one of two new functions:
- VOP_STRATEGY(vp, bp) Call the strategy routine of vp for bp.
- DEV_STRATEGY(bp) Call the d_strategy routine of bp->b_dev for bp.
DEV_STRATEGY(bp) is used only for block-to-block device situations.
From PR kern/13702 from Charles Carvalho. Tested on alpha and
i386 with a Laipac TF10 PPS-capable GPS. The com.c change was
copied wholesale from Charles' z8530tty.c patch.
"rv".
In sysctl_destroyv(), deal with deleting alias nodes, and pass a token
size_t to sysctl_destroy().
In sysctl_free(), check that "node" has not reached "rnode", not that
"pnode" has.
In sysctl_realloc(), don't bother setting sysctl_clen...the value is
unchanged.
- delete ktrsyscall32()
- add a check #ifdef _LP64 to do the conversion if P_32 is set to the
standard ktrsyscall()
- add a couple of similar _LP64/P_32 checks to the systrace code.
this should get systrace working for 32 bit apps as well as complete
ktrace support for "trace_enter/trace_exit" using platforms such as amd64.
XXX: systrace isn't supported on sparc64 currently... (it doesn't use
trace_enter/trace_exit, or have it's own calls to systrace_xxx()...)
jdolecek