Commit Graph

1946 Commits

Author SHA1 Message Date
Alan Cox
26354d4c08 Remove an unused and unimplemented sysctl. (For the record, it was marked
as unimplemented in revision 1.129 nearly six years ago.)
2004-07-12 17:45:37 +00:00
Alan Cox
790bdd0f2e Increase the scope of the page queues lock in vm_page_alloc() to cover
a diagnostic check that accesses the cache queue count.
2004-07-10 22:12:49 +00:00
Alan Cox
fd2d354908 Micro-optimize vmspace for 64-bit architectures: Colocate vm_refcnt and
vm_exitingcnt so that alignment does not result in wasted space.
2004-07-06 17:35:10 +00:00
Bruce M Simpson
9bd86a9861 Properly brucify a string by outdenting it. 2004-07-06 02:27:30 +00:00
Bosko Milekic
0d0837ee6d Introduce debug.nosleepwithlocks sysctl, 0 by default. If set to 1
and WITNESS is not built, then force all M_WAITOK allocations to
M_NOWAIT behavior (transparently).  This is to be used temporarily
if wierd deadlocks are reported because we still have code paths
that perform M_WAITOK allocations with lock(s) held, which can
lead to deadlock.  If WITNESS is compiled, then the sysctl is ignored
and we ask witness to tell us wether we have locks held, converting
to M_NOWAIT behavior only if it tells us that we do.

Note this removes the previous mbuf.h inclusion as well (only needed
by last revision), and cleans up unneeded [artificial] comparisons
to just the mbuf zones.  The problem described above has nothing to
do with previous mbuf wait behavior; it is a general problem.
2004-07-04 16:07:44 +00:00
Brian Feldman
7a708c3626 Reextend the M_WAITOK-disabling-hack to all three of the mbuf-related
zones, and do it by direct comparison of uma_zone_t instead of strcmp.

The mbuf subsystem used to provide M_TRYWAIT/M_DONTWAIT semantics, but
this is mostly no longer the case.  M_WAITOK has taken over the spot
M_TRYWAIT used to have, and for mbuf things, still may return NULL if
the code path is incorrectly holding a mutex going into mbuf allocation
functions.

The M_WAITOK/M_NOWAIT semantics are absolute; though it may deadlock
the system to try to malloc or uma_zalloc something with a mutex held
and M_WAITOK specified, it is absolutely required to not return NULL
and will result in instability and/or security breaches otherwise.
There is still room to add the WITNESS_WARN() to all cases so that
we are notified of the possibility of deadlocks, but it cannot change
the value of the "badness" variable and allow allocation to actually
fail except for the specialized cases which used to be M_TRYWAIT.
2004-07-04 15:59:25 +00:00
Brian Feldman
cf107c1d1a Limit mbuma damage. Suddenly ALL allocations with M_WAITOK are subject
to failing -- that is, allocations via malloc(M_WAITOK) that are required
to never fail -- if WITNESS is not defined.  While everyone should be
running WITNESS, in any case, zone "Mbuf" allocations are really the only
ones that should be screwed with by this hack.

This hack is crashing people, and would continue to do so with or without
WITNESS.  Things shouldn't be allocating with M_WAITOK with locks held,
but it's not okay just to always remove M_WAITOK when !WITNESS.

Reported by:	Bernd Walter <ticso@cicely5.cicely.de>
2004-07-03 18:11:41 +00:00
John Baldwin
0c0b25ae91 Implement preemption of kernel threads natively in the scheduler rather
than as one-off hacks in various other parts of the kernel:
- Add a function maybe_preempt() that is called from sched_add() to
  determine if a thread about to be added to a run queue should be
  preempted to directly.  If it is not safe to preempt or if the new
  thread does not have a high enough priority, then the function returns
  false and sched_add() adds the thread to the run queue.  If the thread
  should be preempted to but the current thread is in a nested critical
  section, then the flag TDF_OWEPREEMPT is set and the thread is added
  to the run queue.  Otherwise, mi_switch() is called immediately and the
  thread is never added to the run queue since it is switch to directly.
  When exiting an outermost critical section, if TDF_OWEPREEMPT is set,
  then clear it and call mi_switch() to perform the deferred preemption.
- Remove explicit preemption from ithread_schedule() as calling
  setrunqueue() now does all the correct work.  This also removes the
  do_switch argument from ithread_schedule().
- Do not use the manual preemption code in mtx_unlock if the architecture
  supports native preemption.
- Don't call mi_switch() in a loop during shutdown to give ithreads a
  chance to run if the architecture supports native preemption since
  the ithreads will just preempt DELAY().
- Don't call mi_switch() from the page zeroing idle thread for
  architectures that support native preemption as it is unnecessary.
- Native preemption is enabled on the same archs that supported ithread
  preemption, namely alpha, i386, and amd64.

This change should largely be a NOP for the default case as committed
except that we will do fewer context switches in a few cases and will
avoid the run queues completely when preempting.

Approved by:	scottl (with his re@ hat)
2004-07-02 20:21:44 +00:00
John Baldwin
bf0acc273a - Change mi_switch() and sched_switch() to accept an optional thread to
switch to.  If a non-NULL thread pointer is passed in, then the CPU will
  switch to that thread directly rather than calling choosethread() to pick
  a thread to choose to.
- Make sched_switch() aware of idle threads and know to do
  TD_SET_CAN_RUN() instead of sticking them on the run queue rather than
  requiring all callers of mi_switch() to know to do this if they can be
  called from an idlethread.
- Move constants for arguments to mi_switch() and thread_single() out of
  the middle of the function prototypes and up above into their own
  section.
2004-07-02 19:09:50 +00:00
John Baldwin
d202e0cccc - Don't use a variable to point to the user area that we only use once.
Just use p2->p_uarea directly instead.
- Remove an old and mostly bogus assertion regarding p2->p_sigacts.
- Use RANGEOF macro ala fork1() to clean up bzero/bcopy of p_stats.
2004-07-02 03:45:07 +00:00
Tor Egge
9174ca7ba3 Initialize result->backing_object_offset before linking result onto the list of
vm objects shadowing source in vm_object_shadow().  This closes a race where
vm_object_collapse() could be called with a partially uninitialized object
argument causing symptoms that looked like hardware problems, e.g.  signal 6,
10, 11 or a /bin/sh busy-waiting for a nonexistant child process.
2004-06-28 20:26:35 +00:00
Andrew Gallatin
b351299ca3 Use MIN() macro rather than ulmin() inline, and fix stray tab
that snuck in with my last commit.

Submitted by: green
2004-06-28 19:58:39 +00:00
Andrew Gallatin
1dad8fe1ed Fix alpha - the use of min() on longs was loosing the high bits and
returning wrong answers, leading to strange values vm2->vm_{s,t,d}size.
2004-06-28 19:15:40 +00:00
David Schultz
17d9d0d049 Update a stale comment. The heuristic to swap processes out based on
the number of pages already paged out was broken in rev 1.10 and
removed in rev 1.11.
2004-06-27 01:58:12 +00:00
Alan Cox
d9dd6bfb56 Remove an unused field from the vmspace structure. 2004-06-26 19:16:35 +00:00
Brian Feldman
2a7be1b6d1 Correct the tracking of various bits of the process's vmspace and vm_map
when not propogated on fork (due to minherit(2)).  Consistency checks
otherwise fail when the vm_map is freed and it appears to have not been
emptied completely, causing an INVARIANTS panic in vm_map_zdtor().

PR:		kern/68017
Submitted by:	Mark W. Krentel <krentel@dreamscape.com>
Reviewed by:	alc
2004-06-24 22:43:46 +00:00
Alan Cox
5e609009de Call vm_pageout_page_stats() with the page queues lock held. 2004-06-24 04:08:43 +00:00
Alan Cox
1aab16a6b6 Remove spl calls. 2004-06-24 03:13:30 +00:00
Bosko Milekic
cc822cb53e Make uma_mtx MTX_RECURSE. Here's why:
The general UMA lock is a recursion-allowed lock because
there is a code path where, while we're still configured
to use startup_alloc() for backend page allocations, we
may end up in uma_reclaim() which calls zone_foreach(zone_drain),
which grabs uma_mtx, only to later call into startup_alloc()
because while freeing we needed to allocate a bucket.  Since
startup_alloc() also takes uma_mtx, we need to be able to
recurse on it.

This exact explanation also added as comment above mtx_init().

Trace showing recursion reported by: Peter Holm <peter-at-holm.cc>
2004-06-23 21:59:03 +00:00
Bruce M Simpson
0e3fe6e3e6 In swap_pager_getpages(), bp->b_dev can be NULL, particularly for the
case of NFS mounted swap, so do not try to dereference it.

While we're here, brucify the printf() call which happens when we
time out on acquisition of vm_page_queue_mtx.

PR:		kern/67898
Submitted by:	bde (style)
2004-06-23 15:15:07 +00:00
Alan Cox
0a2df4773c Remove spl() calls. Update comments to reflect the removal of spl() calls.
Remove '\n' from panic() format strings.  Remove some blank lines.
2004-06-19 04:19:47 +00:00
Poul-Henning Kamp
f3732fd15b Second half of the dev_t cleanup.
The big lines are:
	NODEV -> NULL
	NOUDEV -> NODEV
	udev_t -> dev_t
	udev2dev() -> findcdev()

Various minor adjustments including handling of userland access to kernel
space struct cdev etc.
2004-06-17 17:16:53 +00:00
Alan Cox
d45f21f31a Do not preset PG_BUSY on VM_ALLOC_NOOBJ pages. Such pages are not
accessible through an object.  Thus, PG_BUSY serves no purpose.
2004-06-17 06:16:58 +00:00
Poul-Henning Kamp
89c9c53da0 Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.
2004-06-16 09:47:26 +00:00
Julian Elischer
fa88511615 Nice, is a property of a process as a whole..
I mistakenly moved it to the ksegroup when breaking up the process
structure. Put it back in the proc structure.
2004-06-16 00:26:31 +00:00
Brian Feldman
408a38478a Make contigmalloc() more reliable:
1. Remove a race whereby contigmalloc() would deadlock against the
   running processes in the system if they kept reinstantiating
   the memory on the active and inactive page queues that it was
   trying to flush out.  The process doing the contigmalloc() would
   sit in "swwrt" forever and the swap pager would be going at full
   force, but never get anywhere.  Instead of doing it until the
   queues are empty, launder for as many iterations as there are
   pages in the queue.
2. Do all laundering to swap synchronously; previously, the vnode
   laundering was synchronous and the swap laundering not.
3. Increase the number of launder-or-allocate passes to three, from
   two, while failing without bothering to do all the laundering on
   the third pass if allocation was not possible.  This effectively
   gives exactly two chances to launder enough contiguous memory,
   helpful with high memory churn where a lot of memory from one pass
   to the next (and during a single laundering loop) becomes dirtied
   again.

I can now reliably hot-plug hardware requiring a 256KB contigmalloc()
without having the kldload/cbb ithread sit around failing to make
progress, while running a busy X session.  Previously, it took killing
X to get contigmalloc() to get further (that is, quiescing the system),
and even then contigmalloc() returned failure.
2004-06-15 01:02:00 +00:00
Poul-Henning Kamp
1930e303cf Deorbit COMPAT_SUNOS.
We inherited this from the sparc32 port of BSD4.4-Lite1.  We have neither
a sparc32 port nor a SunOS4.x compatibility desire these days.
2004-06-11 11:16:26 +00:00
Bosko Milekic
7fd8788213 Backout previous change, I think Julian has a better solution which
does not require type-stable refcnts here.
2004-06-09 20:50:08 +00:00
Bosko Milekic
e66468ea7a Make the slabrefzone, the zone from which we allocated slabs with
internal reference counters, UMA_ZONE_NOFREE.  This way, those slabs
(with their ref counts) will be effectively type-stable, then using
a trick like this on the refcount is no longer dangerous:

        MEXT_REM_REF(m);
        if (atomic_cmpset_int(m->m_ext.ref_cnt, 0, 1)) {
                if (m->m_ext.ext_type == EXT_PACKET) {
                        uma_zfree(zone_pack, m);
                        return;
                } else if (m->m_ext.ext_type == EXT_CLUSTER) {
                        uma_zfree(zone_clust, m->m_ext.ext_buf);
                        m->m_ext.ext_buf = NULL;
                } else {
                        (*(m->m_ext.ext_free))(m->m_ext.ext_buf,
                            m->m_ext.ext_args);
                        if (m->m_ext.ext_type != EXT_EXTREF)
                                free(m->m_ext.ref_cnt, M_MBUF);
                }
        }
        uma_zfree(zone_mbuf, m);

Previously, a second thread hitting the above cmpset might
actually read the refcnt AFTER it has already been freed.  A very
rare occurance.  Now we'll know that it won't be freed, though.

Spotted by: julian, pjd
2004-06-09 19:18:50 +00:00
Alexander Leidinger
b1dabb2606 Remove references to L1 in the comments, according to Alan they are
historical leftovers.

Approved by:	alc
2004-06-07 19:33:05 +00:00
Alan Cox
69c1a910e5 Update stale comments regarding page coloring. 2004-06-05 21:06:42 +00:00
Alan Cox
62326de742 Move the definitions of SWAPBLK_NONE and SWAPBLK_MASK from vm_page.h to
blist.h, enabling the removal of numerous #includes from subr_blist.c.
(subr_blist.c and swap_pager.c are the only users of these definitions.)
2004-06-04 04:03:26 +00:00
Bosko Milekic
b83e441b9f Fix a comment above uma_zsecond_create(), describing its arguments.
It doesn't take 'align' and 'flags' but 'master' instead, which is
a reference to the Master Zone, containing the backing Keg.

Pointed out by: Tim Robbins (tjr)
2004-06-01 01:36:26 +00:00
Bosko Milekic
099a0e588c Bring in mbuma to replace mballoc.
mbuma is an Mbuf & Cluster allocator built on top of a number of
extensions to the UMA framework, all included herein.

Extensions to UMA worth noting:
  - Better layering between slab <-> zone caches; introduce
    Keg structure which splits off slab cache away from the
    zone structure and allows multiple zones to be stacked
    on top of a single Keg (single type of slab cache);
    perhaps we should look into defining a subset API on
    top of the Keg for special use by malloc(9),
    for example.
  - UMA_ZONE_REFCNT zones can now be added, and reference
    counters automagically allocated for them within the end
    of the associated slab structures.  uma_find_refcnt()
    does a kextract to fetch the slab struct reference from
    the underlying page, and lookup the corresponding refcnt.

mbuma things worth noting:
  - integrates mbuf & cluster allocations with extended UMA
    and provides caches for commonly-allocated items; defines
    several zones (two primary, one secondary) and two kegs.
  - change up certain code paths that always used to do:
    m_get() + m_clget() to instead just use m_getcl() and
    try to take advantage of the newly defined secondary
    Packet zone.
  - netstat(1) and systat(1) quickly hacked up to do basic
    stat reporting but additional stats work needs to be
    done once some other details within UMA have been taken
    care of and it becomes clearer to how stats will work
    within the modified framework.

From the user perspective, one implication is that the
NMBCLUSTERS compile-time option is no longer used.  The
maximum number of clusters is still capped off according
to maxusers, but it can be made unlimited by setting
the kern.ipc.nmbclusters boot-time tunable to zero.
Work should be done to write an appropriate sysctl
handler allowing dynamic tuning of kern.ipc.nmbclusters
at runtime.

Additional things worth noting/known issues (READ):
   - One report of 'ips' (ServeRAID) driver acting really
     slow in conjunction with mbuma.  Need more data.
     Latest report is that ips is equally sucking with
     and without mbuma.
   - Giant leak in NFS code sometimes occurs, can't
     reproduce but currently analyzing; brueffer is
     able to reproduce but THIS IS NOT an mbuma-specific
     problem and currently occurs even WITHOUT mbuma.
   - Issues in network locking: there is at least one
     code path in the rip code where one or more locks
     are acquired and we end up in m_prepend() with
     M_WAITOK, which causes WITNESS to whine from within
     UMA.  Current temporary solution: force all UMA
     allocations to be M_NOWAIT from within UMA for now
     to avoid deadlocks unless WITNESS is defined and we
     can determine with certainty that we're not holding
     any locks when we're M_WAITOK.
   - I've seen at least one weird socketbuffer empty-but-
     mbuf-still-attached panic.  I don't believe this
     to be related to mbuma but please keep your eyes
     open, turn on debugging, and capture crash dumps.

This change removes more code than it adds.

A paper is available detailing the change and considering
various performance issues, it was presented at BSDCan2004:
http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf
Please read the paper for Future Work and implementation
details, as well as credits.

Testing and Debugging:
    rwatson,
    brueffer,
    Ketrien I. Saihr-Kesenchedra,
    ...
Reviewed by: Lots of people (for different parts)
2004-05-31 21:46:06 +00:00
Alan Cox
e363785643 Remove a stale comment: PG_DIRTY and PG_FILLED were removed in
revisions 1.17 and 1.12 respectively.
2004-05-30 20:48:15 +00:00
Hiten Pandya
76ce6ff787 Correct typo, vm_page_list_find() is called vm_pageq_find() for quite a
long time, i.e., since the cleanup of the VM Page-queues code done two
years ago.

Reviewed by:	Alan Cox <alc at freebsd.org>,
            	Matthew Dillon <dillon at backplane.com>
2004-05-30 00:42:38 +00:00
Dag-Erling Smørgrav
c53f7ace3a MFS: vm_map.c rev 1.187.2.27 through 1.187.2.29, fix MS_INVALIDATE
semantics but provide a sysctl knob for reverting to old ones.
2004-05-25 18:40:53 +00:00
Dag-Erling Smørgrav
b103b94801 Back out previous commit; it went to the wrong file. 2004-05-25 18:28:52 +00:00
Dag-Erling Smørgrav
9507605f93 MFS: rev 1.187.2.27 through 1.187.2.29, fix MS_INVALIDATE semantics but
provide a sysctl knob for reverting to old ones.
2004-05-25 16:31:49 +00:00
Alan Cox
3ffbc0cd8e Correct two error cases in vm_map_unwire():
1. Contrary to the Single Unix Specification our implementation of
   munlock(2) when performed on an unwired virtual address range has
   returned an error.  Correct this.  Note, however, that the behavior
   of "system" unwiring is unchanged, only "user" unwiring is changed.
   If "system" unwiring is performed on an unwired virtual address
   range, an error is still returned.

2. Performing an errant "system" unwiring on a virtual address range
   that was "user" (i.e., mlock(2)) but not "system" wired would
   incorrectly undo the "user" wiring instead of returning an error.
   Correct this.

Discussed with:  green@
Reviewed by:     tegge@
2004-05-25 05:51:17 +00:00
Alan Cox
4be14af9cf To date, unwiring a fictitious page has produced a panic. The reason
being that PHYS_TO_VM_PAGE() returns the wrong vm_page for fictitious
pages but unwiring uses PHYS_TO_VM_PAGE().  The resulting panic
reported an unexpected wired count.  Rather than attempting to fix
PHYS_TO_VM_PAGE(), this fix takes advantage of the properties of
fictitious pages.  Specifically, fictitious pages will never be
completely unwired.  Therefore, we can keep a fictitious page's wired
count forever set to one and thereby avoid the use of
PHYS_TO_VM_PAGE() when we know that we're working with a fictitious
page, just not which one.

In collaboration with: green@, tegge@
PR: kern/29915
2004-05-22 04:53:51 +00:00
Alan Cox
1bb816d3d1 Restructure vm_page_select_cache() so that adding assertions is easy.
Some of the conditions that caused vm_page_select_cache() to deactivate a
page were wrong.  For example, deactivating an unmanaged or wired page is a
nop.  Thus, if vm_page_select_cache() had ever encountered an unmanaged or
wired page, it would have looped forever.  Now, we assert that the page is
neither unmanaged nor wired.
2004-05-12 04:27:18 +00:00
Alan Cox
f651b12907 Cache queue pages are not mapped. Thus, the pmap_remove_all() by
vm_pageout_scan()'s loop for freeing cache queue pages is unnecessary.
2004-05-12 04:10:35 +00:00
Tim J. Robbins
8eec77b09e To handle orphaned character device vnodes properly in mmap(), check that
v_mount is non-null before dereferencing it. If it's null, behave as if
MNT_NOEXEC was not set on the mount that originally containined it.
2004-05-11 10:26:37 +00:00
Alan Cox
3f39cca96b Cache queue pages are not mapped. Thus, the pmap_remove_all() by
vm_page_alloc() is unnecessary.
2004-05-09 01:00:15 +00:00
Brian Feldman
d9b2500eef In r1.190, vslock() and vsunlock() were bogusly made to do a "user wire"
and a "system unwire."  Make this a "system wire" and "system unwire."

Reviewed by:	alc
2004-05-07 11:43:24 +00:00
Brian Feldman
af7cd0c521 Properly remove MAP_FUTUREWIRE when a vm_map_entry gets torn down.
Previously, mlockall(2) usage would leak MAP_FUTUREWIRE of the process's
vmspace::vm_map and subsequent processes would wire all of their memory.
Coupled with a wired-page leak in vm_fault_unwire(), this would run the
system out of free pages and cause programs to randomly SIGBUS when
faulting in new pages.

(Note that this is not the fix for the latter part; pages are still
 leaked when a wired area is unmapped in some cases.)

Reviewed by:	alc
PR		kern/62930
2004-05-07 00:17:07 +00:00
Alan Cox
5a32489377 Make vm_page's PG_ZERO flag immutable between the time of the page's
allocation and deallocation.  This flag's principal use is shortly after
allocation.  For such cases, clearing the flag is pointless.  The only
unusual use of PG_ZERO is in vfs_bio_clrbuf().  However, allocbuf() never
requests a prezeroed page.  So, vfs_bio_clrbuf() never sees a prezeroed
page.

Reviewed by:	tegge@
2004-05-06 05:03:23 +00:00
Alan Cox
8a3ef85721 Zero the physical page only if it is invalid and not prezeroed. 2004-04-25 07:58:59 +00:00
Alan Cox
e265f05414 Add a VM_OBJECT_LOCK_ASSERT() call. Remove splvm() and splx() calls. Move
a comment.
2004-04-24 23:23:36 +00:00