on a non-blocking pipe in cases where select(2) returns the file
descriptor as ready for write. This in turns causes libc_r, for
one, to busy wait in such cases.
Note: it is a quick performance fix, a more complex fix might be
required in case this turns out to have unexpected side effects.
Reviewed by: silby
MFC after: 3 days
thread's pid to make debugging easier for people who don't want to have to
use the intended tool for these panics (witness).
Indirectly prodded by: kris
use "\n\" instead of "\" at the end of each source line, and don't use
semicolons). Fixed some older style bugs on the same lines (mainly
English errors in comments).
1) The race has to do with zone destruction. From the zone destructor we
would lock the zone, set the working set size to 0, then unlock the zone,
drain it, and then free the structure. Within the window following the
working-set-size set to 0 and unlocking of the zone and the point where
in zone_drain we re-acquire the zone lock, the uma timer routine could
have fired off and changed the working set size to something non-zero,
thereby potentially preventing us from completely freeing slabs before
destroying the zone (and thus leaking them).
2) The leak has to do with zone destruction as well. When destroying a
zone we would take care to free all the buckets cached in the zone, but
although we would drain the pcpu cache buckets, we would not free them.
This resulted in leaking a couple of bucket structures (512 bytes each)
per cpu on SMP during zone destruction.
While I'm here, also silence GCC warnings by turning uma_slab_alloc()
from inline to real function. It's too big to be an inline.
Reviewed by: JeffR
a long-standing mistake in the way a portion of a pipe's KVA is
allocated. Specifically, kmem_alloc_pageable() is inappropriate
for use in the "direct" case because it allows a preceding vm map entry
and vm object to be extended to support the new KVA allocation.
However, the direct case KVA allocation should not have a backing
vm object. This is corrected by using kmem_alloc_nofault().
Submitted by: tegge (with the above explanation by me)
tsb_foreach(), 0 signals to terminate the tsb traversal, so when
tsb_foreach() was used in pmap_protect() (which only happens when
the area to be protected is larger than PMAP_TSB_THRESH = 16MB), only
the first tsb entry in the specified range would be protected.
Reported by: Andrew Belashov <bel@orel.ru>
("UMA Zone") carefully, because it does not have pcpu caches allocated
at all. In the UP case, we did not catch this because one pcpu cache
is always allocated with the zone, but for the MP case, we were getting
bogus stats for this zone.
Tested by: Lukas Ertl <le@univie.ac.at>
the != operator) only when needed.
This change allows me to check out the current version of release/
makefiles only (co -l) to /tmp/release, and use that directory to
build a release (supplying the correct WORLDDIR).
Without this, attempt to "make release" caused an endless fork bomb
while trying to evaluate FIXCRYPTO, and the only way I could get
away from this on a remote box was to "kill -INT 1", thanks to
tcsh(1) and its internal "kill" command.
- In sysctl_vm_zone use the per cpu locks to read the current cache
statistics this makes them more accurate while under heavy load.
Submitted by: tegge
so not only wastes memory but it can also cause a leak in zones that
will be destroyed later. The problem is that the slab allocation code
places newly created slabs on the partially allocated list because it
assumes that the caller will actually allocate some memory from it.
Failure to do so places an otherwise free slab on the partial slab list
where we wont find it later in zone_drain().
Continuously prodded to fix by: phk (Thanks)
with up to date comments. This fixes booting kernels with boot2
(except for loss of the features provided by loader) and is suitable
for MFC. Contrary to the old comments, most loaders don't clear the bss.
biosboot lost clearing of the bss in a code crunch in 1997, and boot2
never did it.
kan didn't notice the problem with gcc-3.3 putting variables that are
initialized to 0 in the bss until after committing gcc-3.3 because he
was already using essentially this patch. Before gcc-3.3, only the
non-critical `bootdev' variable was clobbered by clearing the bss.
MFC after: 3 days
messages are forwarded as netgraph control messages to the node
that is connected to the manage hook. If that hook is not connected,
the event is lost. Flow control events are converted to netgraph
flow control messages and send along the hook that is connected to
the flow controlled VC. ACR change events are converted to control
messages and sent along the hook for the given VC.
