Commit Graph

267 Commits

Author SHA1 Message Date
Konstantin Belousov
b76278407d Add kernel option KSTACK_USAGE_PROF to sample the stack depth on
interrupts and report the largest value seen as sysctl
debug.max_kstack_used.  Useful to estimate how close the kernel stack
size is to overflow.

In collaboration with:	Larry Baird <lab@gta.com>
Sponsored by:	The FreeBSD Foundation (kib)
MFC after:	1 week
2014-10-04 18:38:14 +00:00
Konstantin Belousov
70978c93b8 If vm_page_grab() allocates a new page, the page is not inserted into
page queue even when the allocation is not wired.  It is
responsibility of the vm_page_grab() caller to ensure that the page
does not end on the vm_object queue but not on the pagedaemon queue,
which would effectively create unpageable unwired page.

In exec_map_first_page() and vm_imgact_hold_page(), activate the page
immediately after unbusying it, to avoid leak.

In the uiomove_object_page(), deactivate page before the object is
unlocked.  There is no leak, since the page is deactivated after
uiomove_fromphys() finished.  But allowing non-queued non-wired page
in the unlocked object queue makes it impossible to assert that leak
does not happen in other places.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-08-13 05:44:08 +00:00
Attilio Rao
3ae10f7477 - Modify vm_page_unwire() and vm_page_enqueue() to directly accept
the queue where to enqueue pages that are going to be unwired.
- Add stronger checks to the enqueue/dequeue for the pagequeues when
  adding and removing pages to them.

Of course, for unmanaged pages the queue parameter of vm_page_unwire() will
be ignored, just as the active parameter today.
This makes adding new pagequeues quicker.

This change effectively modifies the KPI.  __FreeBSD_version will be,
however, bumped just when the full cache of free pages will be
evicted.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc
Tested by:	pho
2014-06-16 18:15:27 +00:00
Bryan Drewery
44f1c91610 Rename global cnt to vm_cnt to avoid shadowing.
To reduce the diff struct pcu.cnt field was not renamed, so
PCPU_OP(cnt.field) is still used. pc_cnt and pcpu are also used in
kvm(3) and vmstat(8). The goal was to not affect externally used KPI.

Bump __FreeBSD_version_ in case some out-of-tree module/code relies on the
the global cnt variable.

Exp-run revealed no ports using it directly.

No objection from:	arch@
Sponsored by:	EMC / Isilon Storage Division
2014-03-22 10:26:09 +00:00
Konstantin Belousov
5944de8ecd Remove the deprecated VM_ALLOC_RETRY flag for the vm_page_grab(9).
The flag was mandatory since r209792, where vm_page_grab(9) was
changed to only support the alloc retry semantic.

Suggested and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
2013-08-22 07:39:53 +00:00
Attilio Rao
c7aebda8a1 The soft and hard busy mechanism rely on the vm object lock to work.
Unify the 2 concept into a real, minimal, sxlock where the shared
acquisition represent the soft busy and the exclusive acquisition
represent the hard busy.
The old VPO_WANTED mechanism becames the hard-path for this new lock
and it becomes per-page rather than per-object.
The vm_object lock becames an interlock for this functionality:
it can be held in both read or write mode.
However, if the vm_object lock is held in read mode while acquiring
or releasing the busy state, the thread owner cannot make any
assumption on the busy state unless it is also busying it.

Also:
- Add a new flag to directly shared busy pages while vm_page_alloc
  and vm_page_grab are being executed.  This will be very helpful
  once these functions happen under a read object lock.
- Move the swapping sleep into its own per-object flag

The KPI is heavilly changed this is why the version is bumped.
It is very likely that some VM ports users will need to change
their own code.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff, kib
Tested by:	gavin, bapt (older version)
Tested by:	pho, scottl
2013-08-09 11:11:11 +00:00
Jeff Roberson
5df87b21d3 Replace kernel virtual address space allocation with vmem. This provides
transparent layering and better fragmentation.

 - Normalize functions that allocate memory to use kmem_*
 - Those that allocate address space are named kva_*
 - Those that operate on maps are named kmap_*
 - Implement recursive allocation handling for kmem_arena in vmem.

Reviewed by:	alc
Tested by:	pho
Sponsored by:	EMC / Isilon Storage Division
2013-08-07 06:21:20 +00:00
Attilio Rao
be99683637 Revert r253939:
We cannot busy a page before doing pagefaults.
Infact, it can deadlock against vnode lock, as it tries to vget().
Other functions, right now, have an opposite lock ordering, like
vm_object_sync(), which acquires the vnode lock first and then
sleeps on the busy mechanism.

Before this patch is reinserted we need to break this ordering.

Sponsored by:	EMC / Isilon storage division
Reported by:	kib
2013-08-05 08:55:35 +00:00
Attilio Rao
3b6714cacb The page hold mechanism is fast but it has couple of fallouts:
- It does not let pages respect the LRU policy
- It bloats the active/inactive queues of few pages

Try to avoid it as much as possible with the long-term target to
completely remove it.
Use the soft-busy mechanism to protect page content accesses during
short-term operations (like uiomove_fromphys()).

After this change only vm_fault_quick_hold_pages() is still using the
hold mechanism for page content access.
There is an additional complexity there as the quick path cannot
immediately access the page object to busy the page and the slow path
cannot however busy more than one page a time (to avoid deadlocks).

Fixing such primitive can bring to complete removal of the page hold
mechanism.

Sponsored by:	EMC / Isilon storage division
Discussed with:	alc
Reviewed by:	jeff
Tested by:	pho
2013-08-04 21:07:24 +00:00
Andriy Gapon
785797c341 rename scheduler->swapper and SI_SUB_RUN_SCHEDULER->SI_SUB_LAST
Also directly call swapper() at the end of mi_startup instead of
relying on swapper being the last thing in sysinits order.

Rationale:

- "RUN_SCHEDULER" was misleading, scheduling already takes place at that stage
- "scheduler" was misleading, the function swaps in the swapped out processes
- another SYSINIT(SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY) could never be
  invoked depending on its relative order with scheduler; this was not obvious
  and the bug actually used to exist

Reviewed by:	kib (ealier version)
MFC after:	14 days
2013-07-24 09:45:31 +00:00
Attilio Rao
002f377ab2 Complete r251452:
Avoid to busy/unbusy a page in cases where there is no need to drop the
vm_obj lock, more nominally when the page is full valid after
vm_page_grab().

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc
2013-06-06 18:19:26 +00:00
Attilio Rao
89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
Andre Oppermann
25c1e16409 Move the corresponding MTX_SYSINIT() next to their struct mtx declaration
to make their relationship more obvious as done with the other such mutexs.
2012-10-26 17:31:35 +00:00
Andrey Zonov
e145130e71 - Remove accounting of locked memory from vsunlock(9) that I missed in r239818.
Approved by:	kib (mentor)
2012-08-30 08:03:33 +00:00
Andrey Zonov
126a63ce6c - Don't take an account of locked memory for current process in vslock(9).
There are two consumers of vslock(9): sysctl code and drm driver.  These
consumers are using locked memory as transient memory, it doesn't belong
to a process's memory.

Suggested by:	avg
Reviewed by:	alc
Approved by:	kib (mentor)
MFC after:	2 weeks
2012-08-29 11:23:59 +00:00
Konstantin Belousov
e878d99718 Move kstack_cache_entry into the private header, and make the
stack cache list header accessible outside vm_glue.c.

MFC after:	1 week
2011-12-16 10:56:16 +00:00
Edward Tomasz Napierala
afcc55f318 All the racct_*() calls need to happen with the proc locked. Fixing this
won't happen before 9.0.  This commit adds "#ifdef RACCT" around all the
"PROC_LOCK(p); racct_whatever(p, ...); PROC_UNLOCK(p)" instances, in order
to avoid useless locking/unlocking in kernels built without "options RACCT".
2011-07-06 20:06:44 +00:00
John Baldwin
e806d352d2 Fix several places to ignore processes that are not yet fully constructed.
MFC after:	1 week
2011-04-06 17:47:22 +00:00
Edward Tomasz Napierala
1ba5ad4210 Add accounting for most of the memory-related resources.
Sponsored by:	The FreeBSD Foundation
Reviewed by:	kib (earlier version)
2011-04-05 20:23:59 +00:00
Konstantin Belousov
50a57dfbec Move repeated MAXSLP definition from machine/vmparam.h to sys/vmmeter.h.
Update the outdated comments describing MAXSLP and the process
selection algorithm for swap out.

Comments wording and reviewed by:	alc
2011-01-09 12:50:44 +00:00
Alan Cox
eb00b276ab Eliminate page queues locking around most calls to vm_page_free(). 2010-05-06 18:58:32 +00:00
Alan Cox
e3ef0d2fcf Push down the acquisition of the page queues lock into vm_page_unwire().
Update the comment describing which lock should be held on entry to
vm_page_wire().

Reviewed by:	kib
2010-05-05 03:45:46 +00:00
Kip Macy
2965a45315 On Alan's advice, rather than do a wholesale conversion on a single
architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
support in the MI code and have only moved vm_page's hold_count
out from under page queue mutex to page lock. This changes
pmap_extract_and_hold on all pmaps.

Supported by: Bitgravity Inc.

Discussed with: alc, jeffr, and kib
2010-04-30 00:46:43 +00:00
Konstantin Belousov
6fb8c0c117 When doing kstack swapin, read as much pages in one run as possible.
Suggested and reviewed by:	alc (previous version)
Tested by:	pho
MFC after:	2 weeks
2010-04-29 09:59:16 +00:00
Alan Cox
7b7d5b6c58 vm_thread_swapout() can safely dirty the page before rather than after
acquiring the page queues lock.
2010-04-19 00:18:14 +00:00
Juli Mallett
ca596a25f0 o) Add a VM find-space option, VMFS_TLB_ALIGNED_SPACE, which searches the
address space for an address as aligned by the new pmap_align_tlb()
   function, which is for constraints imposed by the TLB. [1]
o) Add a kmem_alloc_nofault_space() function, which acts like
   kmem_alloc_nofault() but allows the caller to specify which find-space
   option to use. [1]
o) Use kmem_alloc_nofault_space() with VMFS_TLB_ALIGNED_SPACE to allocate the
   kernel stack address on MIPS. [1]
o) Make pmap_align_tlb() on MIPS align addresses so that they do not start on
   an odd boundary within the TLB, so that they are suitable for insertion as
   wired entries and do not have to share a TLB entry with another mapping,
   assuming they are appropriately-sized.
o) Eliminate md_realstack now that the kstack will be appropriately-aligned on
   MIPS.
o) Increase the number of guard pages to 2 so that we retain the proper
   alignment of the kstack address.

Reviewed by:	[1] alc
X-MFC-after:	Making sure alc has not come up with a better interface.
2010-04-18 22:32:07 +00:00
Alan Cox
6c68c971cb Simplify vm_thread_swapin(). 2010-04-13 06:48:37 +00:00
Alan Cox
ac45ee97c9 Initialize the virtual memory-related resource limits in a single place.
Previously, one of these limits was initialized in two places to a
different value in each place.  Moreover, because an unsigned int was used
to represent the amount of pageable physical memory, some of these limits
were incorrectly initialized on 64-bit architectures.  (Currently, this
error is masked by login.conf's default settings.)

Make vm_thread_swapin() and vm_thread_swapout() static.

Submitted by:	bde (an earlier version)
Reviewed by:	kib
2010-04-11 16:26:07 +00:00
Marcel Moolenaar
1a4fcaebe3 o Introduce vm_sync_icache() for making the I-cache coherent with
the memory or D-cache, depending on the semantics of the platform.
    vm_sync_icache() is basically a wrapper around pmap_sync_icache(),
    that translates the vm_map_t argumument to pmap_t.
o   Introduce pmap_sync_icache() to all PMAP implementation. For powerpc
    it replaces the pmap_page_executable() function, added to solve
    the I-cache problem in uiomove_fromphys().
o   In proc_rwmem() call vm_sync_icache() when writing to a page that
    has execute permissions. This assures that when breakpoints are
    written, the I-cache will be coherent and the process will actually
    hit the breakpoint.
o   This also fixes the Book-E PMAP implementation that was missing
    necessary locking while trying to deal with the I-cache coherency
    in pmap_enter() (read: mmu_booke_enter_locked).

The key property of this change is that the I-cache is made coherent
*after* writes have been done. Doing it in the PMAP layer when adding
or changing a mapping means that the I-cache is made coherent *before*
any writes happen. The difference is key when the I-cache prefetches.
2009-10-21 18:38:02 +00:00
Konstantin Belousov
8a945d109c 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
Konstantin Belousov
f25fa6abb2 Reverse r196640 and r196644 for now. 2009-08-29 21:53:08 +00:00
Konstantin Belousov
c3cf0b476f 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
Alan Cox
0a2e596a93 Eliminate unnecessary obfuscation when testing a page's valid bits. 2009-06-07 19:38:26 +00:00
Alan Cox
d1a6e42ddd If vm_pager_get_pages() returns VM_PAGER_OK, then there is no need to check
the page's valid bits.  The page is guaranteed to be fully valid.  (For the
record, this is documented in vm/vm_pager.h's comments.)
2009-06-06 20:13:14 +00:00
Alan Cox
7a122777c9 vm_thread_swapin() needn't validate any pages. The pages are already
validated by vm_pager_get_pages().
2009-06-05 17:06:20 +00:00
John Baldwin
da7bbd2c08 If a thread that is swapped out is made runnable, then the setrunnable()
routine wakes up proc0 so that proc0 can swap the thread back in.
Historically, this has been done by waking up proc0 directly from
setrunnable() itself via a wakeup().  When waking up a sleeping thread
that was swapped out (the usual case when waking proc0 since only sleeping
threads are eligible to be swapped out), this resulted in a bit of
recursion (e.g. wakeup() -> setrunnable() -> wakeup()).

With sleep queues having separate locks in 6.x and later, this caused a
spin lock LOR (sleepq lock -> sched_lock/thread lock -> sleepq lock).
An attempt was made to fix this in 7.0 by making the proc0 wakeup use
the ithread mechanism for doing the wakeup.  However, this required
grabbing proc0's thread lock to perform the wakeup.  If proc0 was asleep
elsewhere in the kernel (e.g. waiting for disk I/O), then this degenerated
into the same LOR since the thread lock would be some other sleepq lock.

Fix this by deferring the wakeup of the swapper until after the sleepq
lock held by the upper layer has been locked.  The setrunnable() routine
now returns a boolean value to indicate whether or not proc0 needs to be
woken up.  The end result is that consumers of the sleepq API such as
*sleep/wakeup, condition variables, sx locks, and lockmgr, have to wakeup
proc0 if they get a non-zero return value from sleepq_abort(),
sleepq_broadcast(), or sleepq_signal().

Discussed with:	jeff
Glanced at by:	sam
Tested by:	Jurgen Weber  jurgen - ish com au
MFC after:	2 weeks
2008-08-05 20:02:31 +00:00
Jeff Roberson
8df78c41d6 - Make SCHED_STATS more generic by adding a wrapper to create the
variables and sysctl nodes.
 - In reset walk the children of kern_sched_stats and reset the counters
   via the oid_arg1 pointer.  This allows us to add arbitrary counters to
   the tree and still reset them properly.
 - Define a set of switch types to be passed with flags to mi_switch().
   These types are named SWT_*.  These types correspond to SCHED_STATS
   counters and are automatically handled in this way.
 - Make the new SWT_ types more specific than the older switch stats.
   There are now stats for idle switches, remote idle wakeups, remote
   preemption ithreads idling, etc.
 - Add switch statistics for ULE's pickcpu algorithm.  These stats include
   how much migration there is, how often affinity was successful, how
   often threads were migrated to the local cpu on wakeup, etc.

Sponsored by:	Nokia
2008-04-17 04:20:10 +00:00
Jeff Roberson
374ae2a393 - 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
Robert Watson
237fdd787b In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation.  This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.

MFC after:	1 month
Discussed with:	imp, rink
2008-03-16 10:58:09 +00:00
Jeff Roberson
6617724c5f Remove kernel support for M:N threading.
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential.  Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
2008-03-12 10:12:01 +00:00
Jeff Roberson
c5aa6b581d - Pass the priority argument from *sleep() into sleepq and down into
sched_sleep().  This removes extra thread_lock() acquisition and
   allows the scheduler to decide what to do with the static boost.
 - Change the priority arguments to cv_* to match sleepq/msleep/etc.
   where 0 means no priority change.  Catch -1 in cv_broadcastpri() and
   convert it to 0 for now.
 - Set a flag when sleeping in a way that is compatible with swapping
   since direct priority comparisons are meaningless now.
 - Add a sysctl to ule, kern.sched.static_boost, that defaults to on which
   controls the boost behavior.  Turning it off gives better performance
   in some workloads but needs more investigation.
 - While we're modifying sleepq, change signal and broadcast to both
   return with the lock held as the lock was held on enter.

Reviewed by:	jhb, peter
2008-03-12 06:31:06 +00:00
Konstantin Belousov
89b57fcf01 Fix for the panic("vm_thread_new: kstack allocation failed") and
silent NULL pointer dereference in the i386 and sparc64 pmap_pinit()
when the kmem_alloc_nofault() failed to allocate address space. Both
functions now return error instead of panicing or dereferencing NULL.

As consequence, vmspace_exec() and vmspace_unshare() returns the errno
int. struct vmspace arg was added to vm_forkproc() to avoid dealing
with failed allocation when most of the fork1() job is already done.

The kernel stack for the thread is now set up in the thread_alloc(),
that itself may return NULL. Also, allocation of the first process
thread is performed in the fork1() to properly deal with stack
allocation failure. proc_linkup() is separated into proc_linkup()
called from fork1(), and proc_linkup0(), that is used to set up the
kernel process (was known as swapper).

In collaboration with:	Peter Holm
Reviewed by:	jhb
2007-11-05 11:36:16 +00:00
Jeff Roberson
258853ab1c - Redefine p_swtime and td_slptime as p_swtick and td_slptick. This
changes the units from seconds to the value of 'ticks' when swapped
   in/out.  ULE does not have a periodic timer that scans all threads in
   the system and as such maintaining a per-second counter is difficult.
 - Change computations requiring the unit in seconds to subtract ticks
   and divide by hz.  This does make the wraparound condition hz times
   more frequent but this is still in the range of several months to
   years and the adverse effects are minimal.

Approved by:    re
2007-09-21 05:07:07 +00:00
Jeff Roberson
b61ce5b0e6 - Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
   previously the sched_lock.  These bugs have existed for some time.
 - Allow swapout to try each thread in a process individually and then
   swapin the whole process if any of these fail.  This allows us to move
   most scheduler related swap flags into td_flags.
 - Keep ki_sflag for backwards compat but change all in source tools to
   use the new and more correct location of P_INMEM.

Reported by:	pho
Reviewed by:	attilio, kib
Approved by:	re (kensmith)
2007-09-17 05:31:39 +00:00
Jeff Roberson
982d11f836 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 Roberson
1c4bcd050a - Move rusage from being per-process in struct pstats to per-thread in
td_ru.  This removes the requirement for per-process synchronization in
   statclock() and mi_switch().  This was previously supported by
   sched_lock which is going away.  All modifications to rusage are now
   done in the context of the owning thread.  reads proceed without locks.
 - Aggregate exiting threads rusage in thread_exit() such that the exiting
   thread's rusage is not lost.
 - Provide a new routine, rufetch() to fetch an aggregate of all rusage
   structures from all threads in a process.  This routine must be used
   in any place requiring a rusage from a process prior to it's exit.  The
   exited process's rusage is still available via p_ru.
 - Aggregate tick statistics only on demand via rufetch() or when a thread
   exits.  Tick statistics are kept in the thread and protected by sched_lock
   until it exits.

Initial patch by:	attilio
Reviewed by:		attilio, bde (some objections), arch (mostly silent)
2007-06-01 01:12:45 +00:00
Attilio Rao
2feb50bf7d Revert VMCNT_* operations introduction.
Probabilly, a general approach is not the better solution here, so we should
solve the sched_lock protection problems separately.

Requested by: alc
Approved by: jeff (mentor)
2007-05-31 22:52:15 +00:00
Jeff Roberson
222d01951f - define and use VMCNT_{GET,SET,ADD,SUB,PTR} macros for manipulating
vmcnts.  This can be used to abstract away pcpu details but also changes
   to use atomics for all counters now.  This means sched lock is no longer
   responsible for protecting counts in the switch routines.

Contributed by:		Attilio Rao <attilio@FreeBSD.org>
2007-05-18 07:10:50 +00:00
Jeff Roberson
f0393f063a - 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
Julian Elischer
ad1e7d285a Threading cleanup.. part 2 of several.
Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made things overly complicated.
All code in the scheduler that tried to make threaded programs
fair to unthreaded programs.  Libpthread processes will already
do this to some extent and libthr processes already disable it.

Also:
Since this makes such a big change to the scheduler(s), take the opportunity
to rename some structures and elements that had to be moved anyhow.
This makes the code a lot more readable.

The ULE scheduler compiles again but I have no idea if it works.

The 4bsd scheduler still reqires a little cleaning and some functions that now do
ALMOST nothing will go away, but I thought I'd do that as a separate commit.

Tested by David Xu, and Dan Eischen using libthr and libpthread.
2006-12-06 06:34:57 +00:00