Commit Graph

124 Commits

Author SHA1 Message Date
Mateusz Guzik
1c0b34417b Move vmmeter atomic counters into dedicated cache lines
Prior to the change they were subject to extreme false sharing.
In particular this change shaves about 3 seconds real time of -j 80 buildkernel.

Reviewed by:	alc, markj
Differential Revision:	https://reviews.freebsd.org/D12281
2017-09-10 19:00:38 +00:00
Konstantin Belousov
be10b9d5d7 Emulate pre-r317061 ABI.
This restores 32bit-sized accesses to vmcnt sysctls, making old
binaries like top(1), systat(8) and reboot(8) mostly functional on
newer kernel.

Reviewed by:	bde
Sponsored by:	The FreeBSD Foundation
2017-05-02 18:40:41 +00:00
Gleb Smirnoff
83c9dea1ba - Remove 'struct vmmeter' from 'struct pcpu', leaving only global vmmeter
in place.  To do per-cpu stats, convert all fields that previously were
  maintained in the vmmeters that sit in pcpus to counter(9).
- Since some vmmeter stats may be touched at very early stages of boot,
  before we have set up UMA and we can do counter_u64_alloc(), provide an
  early counter mechanism:
  o Leave one spare uint64_t in struct pcpu, named pc_early_dummy_counter.
  o Point counter(9) fields of vmmeter to pcpu[0].pc_early_dummy_counter,
    so that at early stages of boot, before counters are allocated we already
    point to a counter that can be safely written to.
  o For sparc64 that required a whole dummy pcpu[MAXCPU] array.

Further related changes:
- Don't include vmmeter.h into pcpu.h.
- vm.stats.vm.v_swappgsout and vm.stats.vm.v_swappgsin changed to 64-bit,
  to match kernel representation.
- struct vmmeter hidden under _KERNEL, and only vmstat(1) is an exclusion.

This is based on benno@'s 4-year old patch:
https://lists.freebsd.org/pipermail/freebsd-arch/2013-July/014471.html

Reviewed by:	kib, gallatin, marius, lidl
Differential Revision:	https://reviews.freebsd.org/D10156
2017-04-17 17:34:47 +00:00
Warner Losh
fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00
Konstantin Belousov
8b590e9506 Remove redundancy in vmtotal().
There are two instances of inlined unlocks + continue in vmtotal()
switch statements, which are ordinary expressed with break from the
switch case and code after the switch.  Also, the combination of
continue and break statement is redundand.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2016-12-26 19:29:04 +00:00
Mark Johnston
90458813cd Conditionalize PG_CACHE sysctls on COMPAT_FREEBSD11.
Reviewed by:	glebius, imp, jhb
Differential Revision:	https://reviews.freebsd.org/D8736
2016-12-09 18:55:27 +00:00
Mark Johnston
43482f897b Use the official spelling for NULL arguments to typed sysctl handlers.
Reported by:	bde
2016-12-07 01:15:10 +00:00
Mark Johnston
77edd8fa00 Provide dummy sysctls for v_cache_count and v_tcached.
Some utilities (notably top(1)) exit if any of their input sysctls don't
exist, and the removal of the above-mentioned PG_CACHE-related sysctls
makes it difficult to run such utilities on different versions of the
kernel without recompiling.

Requested by:	bde
2016-12-06 22:52:45 +00:00
Alan Cox
bba39b9ae3 Remove PG_CACHED-related fields from struct vmmeter, because they are no
longer used.  More precisely, they are always zero because the code that
decremented and incremented them no longer exists.

Bump __FreeBSD_version to mark this change.

Reviewed by:	kib, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8583
2016-11-22 18:13:46 +00:00
Alan Cox
ebcddc7217 Introduce a new page queue, PQ_LAUNDRY, for storing unreferenced, dirty
pages, specificially, dirty pages that have passed once through the inactive
queue.  A new, dedicated thread is responsible for both deciding when to
launder pages and actually laundering them.  The new policy uses the
relative sizes of the inactive and laundry queues to determine whether to
launder pages at a given point in time.  In general, this leads to more
intelligent swapping behavior, since the laundry thread will avoid pageouts
when the marginal benefit of doing so is low.  Previously, without a
dedicated queue for dirty pages, the page daemon didn't have the information
to determine whether pageout provides any benefit to the system.  Thus, the
previous policy often resulted in small but steadily increasing amounts of
swap usage when the system is under memory pressure, even when the inactive
queue consisted mostly of clean pages.  This change addresses that issue,
and also paves the way for some future virtual memory system improvements by
removing the last source of object-cached clean pages, i.e., PG_CACHE pages.

The new laundry thread sleeps while waiting for a request from the page
daemon thread(s).  A request is raised by setting the variable
vm_laundry_request and waking the laundry thread.  We request launderings
for two reasons: to try and balance the inactive and laundry queue sizes
("background laundering"), and to quickly make up for a shortage of free
pages and clean inactive pages ("shortfall laundering").  When background
laundering is requested, the laundry thread computes the number of page
daemon wakeups that have taken place since the last laundering.  If this
number is large enough relative to the ratio of the laundry and (global)
inactive queue sizes, we will launder vm_background_launder_target pages at
vm_background_launder_rate KB/s.  Otherwise, the laundry thread goes back
to sleep without doing any work.  When scanning the laundry queue during
background laundering, reactivated pages are counted towards the laundry
thread's target.

In contrast, shortfall laundering is requested when an inactive queue scan
fails to meet its target.  In this case, the laundry thread attempts to
launder enough pages to meet v_free_target within 0.5s, which is the
inactive queue scan period.

A laundry request can be latched while another is currently being
serviced.  In particular, a shortfall request will immediately preempt a
background laundering.

This change also redefines the meaning of vm_cnt.v_reactivated and removes
the functions vm_page_cache() and vm_page_try_to_cache().  The new meaning
of vm_cnt.v_reactivated now better reflects its name.  It represents the
number of inactive or laundry pages that are returned to the active queue
on account of a reference.

In collaboration with:	markj
Reviewed by:	kib
Tested by:	pho
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D8302
2016-11-09 18:48:37 +00:00
Mark Johnston
dbbaf04f1e Remove support for idle page zeroing.
Idle page zeroing has been disabled by default on all architectures since
r170816 and has some bugs that make it seemingly unusable. Specifically,
the idle-priority pagezero thread exacerbates contention for the free page
lock, and yields the CPU without releasing it in non-preemptive kernels. The
pagezero thread also does not behave correctly when superpage reservations
are enabled: its target is a function of v_free_count, which includes
reserved-but-free pages, but it is only able to zero pages belonging to the
physical memory allocator.

Reviewed by:	alc, imp, kib
Differential Revision:	https://reviews.freebsd.org/D7714
2016-09-03 20:38:13 +00:00
Konstantin Belousov
d3b9828d0d The vmtotal sysctl handler marks active vm objects to calculate
statistics.  Marking is done by setting the OBJ_ACTIVE flag.  The
flags change is locked, but the problem is that many parts of system
assume that vm object initialization ensures that no other code could
change the object, and thus performed lockless.  The end result is
corrupted flags in vm objects, most visible is spurious OBJ_DEAD flag,
causing random hangs.

Avoid the active object marking, instead provide equally inexact but
immutable is_object_alive() definition for the object mapped state.

Avoid iterating over the processes mappings altogether by using
arguably improved definition of the paging thread as one which sleeps
on the v_free_count.

PR:	204764
Diagnosed by:	pho
Tested by:	pho (previous version)
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Approved by:	re (gjb)
2016-06-21 17:49:33 +00:00
Mark Johnston
d73ce4c698 Remove the v_cache_min and v_cache_max sysctls. They are unused and have
no effect.

Reviewed by:	alc
Sponsored by:	EMC / Isilon Storage Division
2015-09-11 03:00:20 +00:00
John Baldwin
e735691b61 Place VM objects on the object list when created and never remove them.
This is ok since objects come from a NOFREE zone and allows objects to
be locked while traversing the object list without triggering a LOR.

Ensure that objects on the list are marked DEAD while free or stillborn,
and that they have a refcount of zero.  This required updating most of
the pagers to explicitly mark an object as dead when deallocating it.
(Only the vnode pager did this previously.)

Differential Revision:	https://reviews.freebsd.org/D2423
Reviewed by:	alc, kib (earlier version)
MFC after:	2 weeks
Sponsored by:	Norse Corp, Inc.
2015-05-08 19:43:37 +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
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
Andrey Zonov
b3a01bdf1f - Add system wide page faults requiring I/O counter.
Reviewed by:	alc
MFC after:	2 weeks
2013-01-28 12:54:53 +00:00
Alan Cox
2863482058 In the past four years, we've added two new vm object types. Each time,
similar changes had to be made in various places throughout the machine-
independent virtual memory layer to support the new vm object type.
However, in most of these places, it's actually not the type of the vm
object that matters to us but instead certain attributes of its pages.
For example, OBJT_DEVICE, OBJT_MGTDEVICE, and OBJT_SG objects contain
fictitious pages.  In other words, in most of these places, we were
testing the vm object's type to determine if it contained fictitious (or
unmanaged) pages.

To both simplify the code in these places and make the addition of future
vm object types easier, this change introduces two new vm object flags
that describe attributes of the vm object's pages, specifically, whether
they are fictitious or unmanaged.

Reviewed and tested by:	kib
2012-12-09 00:32:38 +00:00
Eitan Adler
33fd7c5628 - The previous commit (r228449) accidentally moved the vm.stats.vm.* sysctls
to vm.stats.sys.  Move them back.

Noticed by:		pho
Reviewed by:	bde (earlier version)
Approved by:	bz
MFC after:		1 week
Pointy hat to:	me
2011-12-14 13:25:00 +00:00
Eitan Adler
3eb9ab5255 Document a large number of currently undocumented sysctls. While here
fix some style(9) issues and reduce redundancy.

PR:		kern/155491
PR:		kern/155490
PR:		kern/155489
Submitted by:	Galimov Albert <wtfcrap@mail.ru>
Approved by:	bde
Reviewed by:	jhb
MFC after:	1 week
2011-12-13 00:38:50 +00:00
John Baldwin
8e6fa660f2 Fix some locking nits with the p_state field of struct proc:
- Hold the proc lock while changing the state from PRS_NEW to PRS_NORMAL
  in fork to honor the locking requirements.  While here, expand the scope
  of the PROC_LOCK() on the new process (p2) to avoid some LORs.  Previously
  the code was locking the new child process (p2) after it had locked the
  parent process (p1).  However, when locking two processes, the safe order
  is to lock the child first, then the parent.
- Fix various places that were checking p_state against PRS_NEW without
  having the process locked to use PROC_LOCK().  Every place was already
  locking the process, just after the PRS_NEW check.
- Remove or reduce the use of PROC_SLOCK() for places that were checking
  p_state against PRS_NEW.  The PROC_LOCK() alone is sufficient for reading
  the current state.
- Reorder fill_kinfo_proc() slightly so it only acquires PROC_SLOCK() once.

MFC after:	1 week
2011-03-24 18:40:11 +00:00
Juli Mallett
6edf6104a9 Use CPU_FOREACH rather than expecting CPUs 0 through mp_ncpus-1 to be present.
Don't micro-optimize the uniprocessor case; use the same loop there.

Submitted by:	Bhanu Prakash
Reviewed by:	kib, jhb
2011-02-12 02:10:08 +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
John Baldwin
013818111a Add a new type of VM object: OBJT_SG. An OBJT_SG object is very similar to
a device pager (OBJT_DEVICE) object in that it uses fictitious pages to
provide aliases to other memory addresses.  The primary difference is that
it uses an sglist(9) to determine the physical addresses for a given offset
into the object instead of invoking the d_mmap() method in a device driver.

Reviewed by:	alc
Approved by:	re (kensmith)
MFC after:	2 weeks
2009-07-24 13:50:29 +00:00
John Baldwin
8a7ef10b71 - Mark all standalone INT/LONG/QUAD sysctl's MPSAFE. This is done
inside the SYSCTL() macros and thus does not need to be done for
  all of the nodes scattered across the source tree.
- Mark the name-cache related sysctl's (including debug.hashstat.*) MPSAFE.
- Mark vm.loadavg MPSAFE.
- Remove GIANT_REQUIRED from vmtotal() (everything in this routine already
  has sufficient locking) and mark vm.vmtotal MPSAFE.
- Mark the vm.stats.(sys|vm).* sysctls MPSAFE.
2009-01-23 22:49:23 +00:00
Julian Elischer
ac957cd271 A bunch of formatting fixes brough to light by, or created by the Vimage commit
a few days ago.
2008-08-20 01:05:56 +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
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
Alan Cox
eaa29f1ce4 Add a counter for the total number of pages cached and support for
reporting the value of this counter in the program "vmstat".

Approved by:	re (rwatson)
2007-07-27 20:01:22 +00:00
Alan Cox
e99a797492 Eliminate dead code.
Approved by:	re (hrs)
2007-07-12 22:23:28 +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
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
Ruslan Ermilov
ef1b7c4804 Remove a redundant pointer-type variable. 2006-11-20 08:33:55 +00:00
Ruslan Ermilov
276096bb3e When counting vm totals, skip unreferenced objects, including
vnodes representing mounted file systems.

Reviewed by:	alc
MFC after:	3 days
2006-11-20 00:16:00 +00:00
Alan Cox
2cf139527c Retire debug.mpsafevm. None of the architectures supported in CVS require
it any longer.
2006-07-21 23:22:49 +00:00
Alan Cox
ff5ff76116 Set debug.mpsafevm to true on PowerPC. (Now, by default, all architectures
in CVS have debug.mpsafevm set to true.)

Tested by: grehan@
2006-07-10 07:08:05 +00:00
Alan Cox
e4c7a7b169 Enable debug.mpsafevm on arm by default.
Tested by: cognet@
2006-06-10 05:29:37 +00:00
Tor Egge
57051fdc4b Close race between vmspace_exitfree() and exit1() and races between
vmspace_exitfree() and vmspace_free() which could result in the same
vmspace being freed twice.

Factor out part of exit1() into new function vmspace_exit().  Attach
to vmspace0 to allow old vmspace to be freed earlier.

Add new function, vmspace_acquire_ref(), for obtaining a vmspace
reference for a vmspace belonging to another process.  Avoid changing
vmspace refcount from 0 to 1 since that could also lead to the same
vmspace being freed twice.

Change vmtotal() and swapout_procs() to use vmspace_acquire_ref().

Reviewed by:	alc
2006-05-29 21:28:56 +00:00
Marcel Moolenaar
23110bedcd Enable debug_mpsafevm on ia64 due to the severe functional regression
caused by recent locking changes when it's off. Revert the logic to
trim down the conditional.

Clued-in by: alc@
2005-05-08 23:56:16 +00:00
John Baldwin
9fd0669542 Tidy vcnt() by moving a duplicated line above #ifdef and removing a useless
variable.
2005-04-12 23:15:28 +00:00
John Baldwin
a5c7ea5b9e Flip the switch and turn mpsafevm on by default for sparc64.
Approved by:	alc
2005-04-04 20:59:02 +00:00
Poul-Henning Kamp
7fbdc92113 sysctl node vm.stats can not be static (for ia64 reasons). 2005-02-11 16:34:14 +00:00
Poul-Henning Kamp
39a79f0c01 Make three SYSCTL_NODEs static 2005-02-10 12:18:36 +00:00
Warner Losh
60727d8b86 /* -> /*- for license, minor formatting changes 2005-01-07 02:29:27 +00:00
Alan Cox
06c98c5dcc Enable debug.mpsafevm by default on alpha. 2004-12-17 17:17:36 +00:00
Peter Wemm
a7bc3102c4 Put on my peril sensitive sunglasses and add a flags field to the internal
sysctl routines and state.  Add some code to use it for signalling the need
to downconvert a data structure to 32 bits on a 64 bit OS when requested by
a 32 bit app.

I tried to do this in a generic abi wrapper that intercepted the sysctl
oid's, or looked up the format string etc, but it was a real can of worms
that turned into a fragile mess before I even got it partially working.

With this, we can now run 'sysctl -a' on a 32 bit sysctl binary and have
it not abort.  Things like netstat, ps, etc have a long way to go.

This also fixes a bug in the kern.ps_strings and kern.usrstack hacks.
These do matter very much because they are used by libc_r and other things.
2004-10-11 22:04:16 +00:00
Alan Cox
b102e653ad Enable debug.mpsafevm by default on amd64 and i386. This enables copy-on-
write and zero-fill faults to run without holding Giant.  It is still
possible to disable Giant-free operation by setting debug.mpsafevm to 0 in
loader.conf.
2004-09-04 05:51:54 +00:00
Alan Cox
c1fbc251cd - Introduce and use a new tunable "debug.mpsafevm". At present, setting
"debug.mpsafevm" results in (almost) Giant-free execution of zero-fill
   page faults.  (Giant is held only briefly, just long enough to determine
   if there is a vnode backing the faulting address.)

   Also, condition the acquisition and release of Giant around calls to
   pmap_remove() on "debug.mpsafevm".

   The effect on performance is significant.  On my dual Opteron, I see a
   3.6% reduction in "buildworld" time.

 - Use atomic operations to update several counters in vm_fault().
2004-08-16 06:16:12 +00:00
Warner Losh
05eb3785e7 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core
2004-04-06 20:15:37 +00:00