- For privileged processes safe two mutex operations.
We may want to consider if this is good idea to use SUSER_ALLOWJAIL here,
but for now I didn't wanted to change the original behaviour.
Reviewed by: rwatson
all of the module event handlers are MP safe yet, so always acquire Giant
for now when invoking module event handlers. Eventually we can add an
MPSAFE flag or some such and add appropriate locking to all module event
handlers.
in 1999, and there are changes to the sysctl names compared to PR,
according to that discussion. The description is in sys/conf/NOTES.
Lines in the GENERIC files are added in commented-out form.
I'll attach the test script I've used to PR.
PR: kern/14584
Submitted by: babkin
protect all linker-related data structures including the contents of
linker file objects and the any linker class data as well. Considering how
rarely the linker is used I just went with the simple solution of
single-threading the whole thing rather than expending a lot of effor on
something more fine-grained and complex. Giant is still explicitly
acquired while registering and deregistering sysctl's as well as in the
elf linker class while calling kmupetext(). The rest of the linker runs
without Giant unless it has to acquire Giant while loading files from a
non-MPSAFE filesystem.
- Add a new function linker_release_module() as a more intuitive complement
to linker_reference_module() that wraps linker_file_unload().
linker_release_module() can either take the module name and version info
passed to linker_reference_module() or it can accept the linker file
object returned by linker_reference_module().
file objects calling a user-specified predicate function on each object.
The iteration terminates either when the entire list has been iterated
over or the predicate function returns a non-zero value.
linker_file_foreach() returns the value returned by the last invocation
of the predicate function. It also accepts a void * context pointer that
is passed to the predicate function as well. Using an iterator function
avoids exposing linker internals to the rest of the kernel making locking
simpler.
- Use linker_file_foreach() instead of walking the list of linker files
manually to lookup ndis files in ndis(4).
- Use linker_file_foreach() to implement linker_hwpmc_list_objects().
in setsockopt so that they can be compared correctly against negative
values. Passing in a negative value had a rather negative effect
on our socket code, making it impossible to open new sockets.
PR: 98858
Submitted by: James.Juran@baesystems.com
MFC after: 1 week
It is similar to debug.kdb.trap, except for it tries to cause a page fault
via a call to an invalid pointer. This can highlight differences between
a fault on data access vs. a fault on code call some CPUs might have.
This appeared as a test for a work \
Sponsored by: RiNet (Cronyx Plus LLC)
basically always violated) invariannts of soreceive(), which assume
that the first mbuf pointer in a receive socket buffer can't change
while the SB_LOCK sleepable lock is held on the socket buffer,
which is precisely what these functions do. No current protocols
invoke these functions, and removing them will help discourage them
from ever being used. I should have removed them years ago, but
lost track of it.
MFC after: 1 week
Prodded almost by accident by: peter
frequency, quality and current value of each available time counter.
At the moment all of these are read-only, but it might make sense to
make some of these read-write in the future.
MFC after: 3 months
filesystem agnostic. We are not touching any file system specific functions
in this code path. Since we have a cache lock, there is really no need to
keep Giant around here.
This eliminates Giant acquisitions for any syscall which is auditing pathnames.
Discussed with: jeff
yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal run-
queues, a timesharing thread which calls yield() syscall should be
moved to inactive queue.
KASSERT(ke->ke_runq == NULL) panic when the sched_add is recursively
called by maybe_preempt.
Reported by: Wojciech A. Koszek < dunstan at freebsd dot czest dot pl >
we intend for the user to be able to unload them later via kldunload(2)
instead of calling linker_load_module() and then directly adjusting the
ref count on the linker file structure. This makes the resulting
consumer code simpler and cleaner and better hides the linker internals
making it possible to sanely lock the linker.
Giant down in it.
- Push Giant down in kern_kldunload() and reorganize it slightly to avoid
using gotos. Also, expose this function to the rest of the kernel.
- Use a 'struct kld_file_stat' on the stack to read data under the lock
and then do one copyout() w/o holding the lock at the end to push the
data out to userland.
linker_file_unload() instead of in the middle of a bunch of code for
the case of dropping the last reference to improve readability and sanity.
While I'm here, remove pointless goto's that were just jumping to a
return statement.
sockets:
1) A sender sends SCM_CREDS message to a reciever, struct cmsgcred;
2) A reciever sets LOCAL_CREDS socket option and gets sender
credentials in control message, struct sockcred.
Both methods use the same control message type SCM_CREDS with the
same control message level SOL_SOCKET, so they are indistinguishable
for the receiver. A difference in struct cmsgcred and struct sockcred
layouts may lead to unwanted effects.
Now for sockets with LOCAL_CREDS option remove all previous linked
SCM_CREDS control messages and then add a control message with
struct sockcred so the process specifically asked for the peer
credentials by LOCAL_CREDS option always gets struct sockcred.
PR: kern/90800
Submitted by: Andrey Simonenko
Regres. tests: tools/regression/sockets/unix_cmsg/
MFC after: 1 month
I picked it up again. The scheduler is forked from ULE, but the
algorithm to detect an interactive process is almost completely
different with ULE, it comes from Linux paper "Understanding the
Linux 2.6.8.1 CPU Scheduler", although I still use same word
"score" as a priority boost in ULE scheduler.
Briefly, the scheduler has following characteristic:
1. Timesharing process's nice value is seriously respected,
timeslice and interaction detecting algorithm are based
on nice value.
2. per-cpu scheduling queue and load balancing.
3. O(1) scheduling.
4. Some cpu affinity code in wakeup path.
5. Support POSIX SCHED_FIFO and SCHED_RR.
Unlike scheduler 4BSD and ULE which using fuzzy RQ_PPQ, the scheduler
uses 256 priority queues. Unlike ULE which using pull and push, the
scheduelr uses pull method, the main reason is to let relative idle
cpu do the work, but current the whole scheduler is protected by the
big sched_lock, so the benefit is not visible, it really can be worse
than nothing because all other cpu are locked out when we are doing
balancing work, which the 4BSD scheduelr does not have this problem.
The scheduler does not support hyperthreading very well, in fact,
the scheduler does not make the difference between physical CPU and
logical CPU, this should be improved in feature. The scheduler has
priority inversion problem on MP machine, it is not good for
realtime scheduling, it can cause realtime process starving.
As a result, it seems the MySQL super-smack runs better on my
Pentium-D machine when using libthr, despite on UP or SMP kernel.
