Commit Graph

66 Commits

Author SHA1 Message Date
bryanv
1b4affdd25 Do not use potentially stale thread in kthread_add()
When an existing process is provided, the thread selected to use
to initialize the new thread could have exited and be reaped.
Acquire the proc lock earlier to ensure the thread remains valid.

Reviewed by:	jhb, julian (previous version)
MFC after:	3 days
2013-08-17 17:02:43 +00:00
kib
dcb105721a Stop treating td_sigmask specially for the purposes of new thread
creation. Move it into the copied region of the struct thread.

Update some comments.

Requested by:	bde
X-MFC after:	never
2012-05-26 20:03:47 +00:00
delphij
53e510d1ef Revert previous revision, misunderstood the code :( 2012-05-11 23:43:32 +00:00
delphij
f7e33a4a67 Release proc lock after setting signal queue.
PR:		kern/167727
Submitted by:	Jinjun Gao <gjinjun gmail com>
MFC after:	2 weeks
2012-05-11 23:41:52 +00:00
jhb
4fea355eb2 Add a new sched_clear_name() method to the scheduler interface to clear
the cached name used for KTR_SCHED traces when a thread's name changes.
This way KTR_SCHED traces (and thus schedgraph) will notice when a thread's
name changes, most commonly via execve().

MFC after:	2 weeks
2012-03-08 19:41:05 +00:00
rstone
d657a808e1 Whenever a new kernel thread is spawned, explicitly clear any CPU affinity
set on the new thread.  This prevents the thread from inadvertently
inheriting affinity from a random sibling.

Submitted by:	attilio
Tested by:	pho
MFC after:	1 week
2012-02-04 16:49:29 +00:00
jonathan
5ecd1c9d40 Add experimental support for process descriptors
A "process descriptor" file descriptor is used to manage processes
without using the PID namespace. This is required for Capsicum's
Capability Mode, where the PID namespace is unavailable.

New system calls pdfork(2) and pdkill(2) offer the functional equivalents
of fork(2) and kill(2). pdgetpid(2) allows querying the PID of the remote
process for debugging purposes. The currently-unimplemented pdwait(2) will,
in the future, allow querying rusage/exit status. In the interim, poll(2)
may be used to check (and wait for) process termination.

When a process is referenced by a process descriptor, it does not issue
SIGCHLD to the parent, making it suitable for use in libraries---a common
scenario when using library compartmentalisation from within large
applications (such as web browsers). Some observers may note a similarity
to Mach task ports; process descriptors provide a subset of this behaviour,
but in a UNIX style.

This feature is enabled by "options PROCDESC", but as with several other
Capsicum kernel features, is not enabled by default in GENERIC 9.0.

Reviewed by: jhb, kib
Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc
2011-08-18 22:51:30 +00:00
jhb
59c5693c6f - Properly initialize the base priority (td_base_pri) of thread0 to PVM
to match the desired priority in td_priority.  Otherwise the first time
  thread0 used a borrowed priority it would drop down to PUSER instead of
  PVM.
- Explicitly initialize the starting priority of new kprocs to PVM to
  avoid inheriting some random priority from thread0.

MFC after:	2 weeks
2011-01-06 22:26:00 +00:00
jhb
dd9fb27817 kproc_exit() is already marked __dead2 so a NOTREACHED comment here isn't
needed for lint.

Submitted by:	bde
2011-01-04 13:16:28 +00:00
jhb
22fce0b1c2 Small whitespace nits and add a comment explaining why kthread_exit() can
call kproc_exit() that was lost earlier.
2011-01-03 16:29:00 +00:00
davidxu
841633e7b6 In thr_exit() and kthread_exit(), only remove thread from
hash if it can directly exit, otherwise let exit1() do it.
The change should be in r213950, but for unknown reason,
it was lost.
2010-10-23 13:16:39 +00:00
davidxu
55194e796c Create a global thread hash table to speed up thread lookup, use
rwlock to protect the table. In old code, thread lookup is done with
process lock held, to find a thread, kernel has to iterate through
process and thread list, this is quite inefficient.
With this change, test shows in extreme case performance is
dramatically improved.

Earlier patch was reviewed by: jhb, julian
2010-10-09 02:50:23 +00:00
jhb
b7fc8e97f1 Allow a const char * to be passed as the process name to kproc_kthread_add()
without generating a warning.

MFC after:	1 month
2010-05-21 17:14:36 +00:00
attilio
3138bddc87 Use the cached value within comparison.
Submitted by:	jhb
2010-02-19 15:10:05 +00:00
attilio
d4d3373f23 Fix the grammar.
Submitted by:	Brandon Gooch <bgooch at se dot edu>
2010-02-19 15:03:55 +00:00
attilio
5687771459 Fix a race in regard of p_numthreads.
Submitted by:	Giovanni Trematerra
		<giovanni dot trematerra at gmail dot com>
2010-02-19 14:59:41 +00:00
attilio
a4281bb884 - Fix the kthread_{suspend, resume, suspend_check}() locking.
In the current code, the locking is completely broken and may lead
  easilly to deadlocks. Fix it by using the proc_mtx, linked to the
  suspending thread, as lock for the operation.  Keep using the
  thread_lock for setting and reading the flag even if it is not entirely
  necessary (atomic ops may do it as well, but this way the code is more
  readable).
- Fix a deadlock within kthread_suspend().
  The suspender should not sleep on a different channel wrt the suspended
  thread, or, otherwise, the awaker should wakeup both. Uniform the
  interface to what the kproc_* counterparts do (sleeping on the same
  channel).
- Change the kthread_suspend_check() prototype.
  kthread_suspend_check() always assumes curthread and must only refer to
  it, so skip the thread pointer as it may be easilly mistaken.
  If curthread is not a kthread, the system will panic.

In collabouration with:	jhb
Tested by:		Giovanni Trematerra
			<giovanni dot trematerra at gmail dot com>
MFC:			2 weeks
2010-01-24 15:07:00 +00:00
kib
bae5df8cbb Reintroduce the r196640, after fixing the problem with my testing.
Remove the altkstacks, instead instantiate threads with kernel stack
allocated with the right size from the start. For the thread that has
kernel stack cached, verify that requested stack size is equial to the
actual, and reallocate the stack if sizes differ [1].

This fixes the bug introduced by r173361 that was committed several days
after r173004 and consisted of kthread_add(9) ignoring the non-default
kernel stack size.

Also, r173361 removed the caching of the kernel stacks for a non-first
thread in the process. Introduce separate kernel stack cache that keeps
some limited amount of preallocated kernel stacks to lower the latency
of thread allocation. Add vm_lowmem handler to prune the cache on
low memory condition. This way, system with reasonable amount of the
threads get lower latency of thread creation, while still not exhausting
significant portion of KVA for unused kstacks.

Submitted by:	peter [1]
Discussed with:	jhb, julian, peter
Reviewed by:	jhb
Tested by:	pho (and retested according to new test scenarious)
MFC after:	1 week
2009-09-01 11:41:51 +00:00
kib
d105721a22 Reverse r196640 and r196644 for now. 2009-08-29 21:53:08 +00:00
kib
9e8ade6852 Remove the altkstacks, instead instantiate threads with kernel stack
allocated with the right size from the start. For the thread that has
kernel stack cached, verify that requested stack size is equial to the
actual, and reallocate the stack if sizes differ [1].

This fixes the bug introduced by r173361 that was committed several days
after r173004 and consisted of kthread_add(9) ignoring the non-default
kernel stack size.

Also, r173361 removed the caching of the kernel stacks for a non-first
thread in the process. Introduce separate kernel stack cache that keeps
some limited amount of preallocated kernel stacks to lower the latency
of thread allocation. Add vm_lowmem handler to prune the cache on
low memory condition. This way, system with reasonable amount of the
threads get lower latency of thread creation, while still not exhausting
significant portion of KVA for unused kstacks.

Submitted by:	peter [1]
Discussed with:	jhb, julian, peter
Reviewed by:	jhb
Tested by:	pho
MFC after:	1 week
2009-08-29 13:28:02 +00:00
antoine
4dc3acdf62 Kill a dead variable
PR:		126223
Submitted by:	Mateusz Guzik
2008-08-03 21:07:19 +00:00
julian
2ddf06099d Document the kproc_kthread_add() call
and fix a small detail of its implementation.
MFC after: 1 week
2008-04-29 22:43:15 +00:00
jeff
46f09d5bc3 - Relax requirements for p_numthreads, p_threads, p_swtick, and p_nice from
requiring the per-process spinlock to only requiring the process lock.
 - Reflect these changes in the proc.h documentation and consumers throughout
   the kernel.  This is a substantial reduction in locking cost for these
   fields and was made possible by recent changes to threading support.
2008-03-19 06:19:01 +00:00
jhb
b113160d81 Acquire the process mutex and spin locks before calling thread_exit() in
kthread_exit() to fix panics when using INVARIANTS.
2007-11-15 21:45:17 +00:00
julian
93719028ad Add support for the pre-exisiting module shutdoen handshake.
Fix some comments.
2007-10-27 00:54:16 +00:00
julian
4eb58f88d1 If kthread_exit() is called on the last kthread in a kproc, then
all the work in kproc_exit must be done.
We don't actually have a user of this yet but why leave it to chance.
2007-10-26 22:18:20 +00:00
julian
b6e413a633 kthread_exit needs no stinkin argument. 2007-10-26 17:03:22 +00:00
julian
11e1aa0d18 Introduce a way to make pure kernal threads.
kthread_add() takes the same parameters as the old kthread_create()
plus a pointer to a process structure, and adds a kernel thread
to that process.

kproc_kthread_add() takes the parameters for kthread_add,
plus a process name and a pointer to a pointer to a process instead of just
a pointer, and if the proc * is NULL, it creates the process to the
specifications required, before adding the thread to it.

All other old kthread_xxx() calls return, but act on (struct thread *)
instead of (struct proc *). One reason to change the name is so that
any old kernel modules that are lying around and expect kthread_create()
to make a process will not just accidentally link.

fix top to show  kernel threads by their thread name in -SH mode
add a tdnam formatting option to ps to show thread names.

make all idle threads actual kthreads and put them into their own idled process.
make all interrupt threads kthreads and put them in an interd process
(mainly for aesthetic and accounting reasons)
rename proc 0 to be 'kernel' and it's swapper thread is now 'swapper'

man page fixes to follow.
2007-10-26 08:00:41 +00:00
julian
51d643caa6 Rename the kthread_xxx (e.g. kthread_create()) calls
to kproc_xxx as they actually make whole processes.
Thos makes way for us to add REAL kthread_create() and friends
that actually make theads. it turns out that most of these
calls actually end up being moved back to the thread version
when it's added. but we need to make this cosmetic change first.

I'd LOVE to do this rename in 7.0  so that we can eventually MFC the
new kthread_xxx() calls.
2007-10-20 23:23:23 +00:00
jeff
91d1501790 Commit 14/14 of sched_lock decomposition.
- Use thread_lock() rather than sched_lock for per-thread scheduling
   sychronization.
 - Use the per-process spinlock rather than the sched_lock for per-process
   scheduling synchronization.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
2007-06-05 00:00:57 +00:00
jeff
474b917526 - Remove setrunqueue and replace it with direct calls to sched_add().
setrunqueue() was mostly empty.  The few asserts and thread state
   setting were moved to the individual schedulers.  sched_add() was
   chosen to displace it for naming consistency reasons.
 - Remove adjustrunqueue, it was 4 lines of code that was ifdef'd to be
   different on all three schedulers where it was only called in one place
   each.
 - Remove the long ifdef'd out remrunqueue code.
 - Remove the now redundant ts_state.  Inspect the thread state directly.
 - Don't set TSF_* flags from kern_switch.c, we were only doing this to
   support a feature in one scheduler.
 - Change sched_choose() to return a thread rather than a td_sched.  Also,
   rely on the schedulers to return the idlethread.  This simplifies the
   logic in choosethread().  Aside from the run queue links kern_switch.c
   mostly does not care about the contents of td_sched.

Discussed with:	julian

 - Move the idle thread loop into the per scheduler area.  ULE wants to
   do something different from the other schedulers.

Suggested by:	jhb

Tested on:	x86/amd64 sched_{4BSD, ULE, CORE}.
2007-01-23 08:46:51 +00:00
jhb
c5b2640750 Don't do a PHOLD() in kthread_create() w/o a matching PRELE() in
kthread_exit().  Rather than add the missing PRELE() I chose to just
axe the PHOLD() since it was redundant with the P_SYSTEM flag.

MFC after:	1 week
2006-02-22 17:21:45 +00:00
jhb
db29bc1e15 - Move the wakeup() for exiting kthreads out of exit1() and into
kthread_exit() as that is cleaner and less obscured.  It also does the
  wakeup sooner.
- Add some comments to kthread_exit().
2006-02-06 21:56:13 +00:00
imp
20280f1431 /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 23:35:40 +00:00
julian
e9d9514975 Give setrunqueue() and sched_add() more of a clue as to
where they are coming from and what is expected from them.

MFC after:	2 days
2004-09-01 02:11:28 +00:00
obrien
3b8fff9e4c Use __FBSDID(). 2003-06-11 00:56:59 +00:00
jhb
89a4eb17de - Merge struct procsig with struct sigacts.
- Move struct sigacts out of the u-area and malloc() it using the
  M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
  sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
  that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
  and thread_stopped() are now MP safe.

Reviewed by:	arch@
Approved by:	re (rwatson)
2003-05-13 20:36:02 +00:00
des
8ed712ead1 Instead of recording the Unix time in a process when it starts, record the
uptime.  Where necessary, convert it back to Unix time by adding boottime
to it.  This fixes a potential problem in the accounting code, which would
compute the elapsed time incorrectly if the Unix time was stepped during
the lifetime of the process.
2003-05-01 16:59:23 +00:00
jhb
c94962975b fork1() already sets PS_INMEM, so don't set it again. This lets us push
sched_lock down slightly so that it isn't needed in the RFSTOPPED case.
2003-04-17 22:28:28 +00:00
scottl
3a150bca9c Some kernel threads try to do significant work, and the default KSTACK_PAGES
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create.  Passing the
value 0 prevents the alternate kstack from being created.  Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.

Reviewed by:	jake, peter, jhb
2002-10-02 07:44:29 +00:00
jmallett
7a693db242 Back our kernel support for reliable signal queues.
Requested by:	rwatson, phk, and many others
2002-10-01 17:15:53 +00:00
jmallett
0341f71df1 First half of implementation of ksiginfo, signal queues, and such. This
gets signals operating based on a TailQ, and is good enough to run X11,
GNOME, and do job control.  There are some intricate parts which could be
more refined to match the sigset_t versions, but those require further
evaluation of directions in which our signal system can expand and contract
to fit our needs.

After this has been in the tree for a while, I will make in kernel API
changes, most notably to trapsignal(9) and sendsig(9), to use ksiginfo
more robustly, such that we can actually pass information with our
(queued) signals to the userland.  That will also result in using a
struct ksiginfo pointer, rather than a signal number, in a lot of
kern_sig.c, to refer to an individual pending signal queue member, but
right now there is no defined behaviour for such.

CODAFS is unfinished in this regard because the logic is unclear in
some places.

Sponsored by:	New Gold Technology
Reviewed by:	bde, tjr, jake [an older version, logic similar]
2002-09-30 20:20:22 +00:00
julian
5702a380a5 Completely redo thread states.
Reviewed by:	davidxu@freebsd.org
2002-09-11 08:13:56 +00:00
julian
aa2dc0a5d9 Part 1 of KSE-III
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by:	Almost everyone who counts
	(at various times, peter, jhb, matt, alfred, mini, bernd,
	and a cast of thousands)

	NOTE: this is still Beta code, and contains lots of debugging stuff.
	expect slight instability in signals..
2002-06-29 17:26:22 +00:00
peter
4289b50433 Fix a couple of style bugs introduced (or touched by) previous commit. 2002-02-07 23:06:26 +00:00
julian
b5eb64d6f0 Pre-KSE/M3 commit.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.

Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
2002-02-07 20:58:47 +00:00
peter
12f2610cb5 Use a different mechanism to get the vnlru process to wake up and notice
the shutdown request at reboot/halt time.
Disable the printf 'vnlru process getting nowhere, pausing...' and instead
export the count to the debug.vnlru_nowhere sysctl.
2001-12-19 01:31:12 +00:00
peter
63c937a8f7 Commit the better version that I had a while ago. This has only one
reference to curthread.  (#define curproc (curthread->td_proc)).
2001-11-12 08:53:34 +00:00
dillon
9a4e2a07a8 When curproc is used repeatedly store curproc into a local
variable to reduce generated code.  This is a test case.
2001-11-12 08:42:20 +00:00
julian
5596676e6c KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +00:00