the revived code.
vm pages newly allocated are marked busy (PG_BUSY), thus calling
vm_page_delete before the pages has been freed or unbusied will
cause a deadlock since vm_page_object_page_remove will wait for the
busy flag to be cleared. This can be triggered by calling malloc
with size > PAGE_SIZE and the M_NOWAIT flag on systems low on
physical free memory.
A kernel module that reproduces the problem, written by Logan Gabriel
<logan@mail.2cactus.com>, can be found in the freebsd-hackers mail
archive (12 Apr 2001). The problem was recently noticed again by
Archie Cobbs <archie@dellroad.org>.
Reviewed by: dillon
simply need to prevent switching from another CPU and do not need
interrupts disabled.
- Add a comment to witness_list() about why displaying spin locks for
threads on other CPU's really is just a bad idea and probably shouldn't
be done.
and commenting of NETSMB, NETWMBCRYPTO, and SMBFS. In NOTES, they
had all floated to the bottom of the file with the list of seemingly
random and unclassified kernel options. This change moves them back
up to the network protocol and file system areas, and also documents
the dependencies.
This is belived to be the only place where a soft reference to a vnode
is held with no sort of hard reference, consequently this change should
allow us to free(9) vnodes from the freelist after properly cleaning
them up.
Reviewed by: dillon
it worked- but I ran into a case with a 2204 where commands were being lost
right and left. Best be safe.
For target mode, or things called if we call isp_handle_other response- note
that we might have dropped locks by changing the output pointer so we bail
from the loop. It's the responsibility of the entity dropping the lock to
make sure that we let the f/w know we've read thus far into the response
queue (else we begin processing the same entries again- blech!).
MFC after: 1 day
the upcoming 7.4 family (7xxx controllers).
- improved error reporting and handling
- more diagnostic output
- add extra command packet definitions
- merge sources again with -stable
than the other implementations; we have complete control over the tlb, so we
only demap specific pages. We take advantage of the ranged tlb flush api
to send one ipi for a range of pages, and due to the pm_active optimization
we rarely send ipis for demaps from user pmaps.
Remove now unused routines to load the tlb; this is only done once outside
of the tlb fault handlers.
Minor cleanups to the smp startup code.
This boots multi user with both cpus active on a dual ultra 60 and on a
dual ultra 2.
Due to allocating tlb contexts on the fly, we only ever need to demap the
primary context, non-primary contexts have already been implicitly flushed
by context switching. All we really need to tell is if its a kernel demap
or not, and its easier just to compare against the kernel_pmap which is a
constant.
the context is not actually stolen, as it would be for i386. Instead of
deactivating a user vmspace immediately when switching out, and recycling
its tlb context, wait until the next context switch to a different user
vmspace. In this way we can switch from a user process to any number of
kernel threads and back to the same user process again, without losing any
of its mappings in the tlb that would not already be knocked by the automatic
replacement algorithm. This is not expected to have a measurable performance
improvement on the machines we currently run on, but it sounds cool and makes
the sparc64 port SMPng buzz word compliant.
to exhaust all kmaps. The only reward for setting maxproc
to a value which will cause kmap exhaustion is a panic
during a forkbomb attack.
MFC after: 3 days
