Commit Graph

240 Commits

Author SHA1 Message Date
Alan Cox
22cf98d1f3 The intention of r254304 was to scan the active queue continuously.
However, I've observed the active queue scan stopping when there are
frequent free page shortages and the inactive queue is steadily refilled
by other mechanisms, such as the sequential access heuristic in vm_fault()
or madvise(2).  To remedy this problem, record the time of the last active
queue scan, and always scan a number of pages proportional to the time
since the last scan, regardless of whether that last scan was a
timeout-triggered ("pass == 0") or free-page-shortage-triggered ("pass >
0") scan.

Also, on a timeout-triggered scan, allow a full scan of the active queue
when the system is short of inactive pages.

Reviewed by:	kib
MFC after:	6 weeks
Sponsored by:	EMC / Isilon Storage Division
2015-07-08 17:45:59 +00:00
Gleb Smirnoff
e3ed82bcf7 Add flag VM_ALLOC_NOWAIT for vm_page_grab() that prevents sleeping and
allows the function to fail.

Reviewed by:	kib, alc
Sponsored by:	Nginx, Inc.
2014-12-22 09:02:21 +00:00
Gleb Smirnoff
89fc8bdbb6 Document flags of vm_page allocation functions.
Reviewed by:	alc
2014-12-22 08:59:44 +00:00
Konstantin Belousov
afb69e6b3e Adapt vm_page_aflag_set(PGA_WRITEABLE) to the locking of
pmap_enter(PMAP_ENTER_NOSLEEP).  The PGA_WRITEABLE flag can be set
when either the page is busied, or the owner object is locked.

Update comments, move all assertions about page state when
PGA_WRITEABLE flag is set, into new helper
vm_page_assert_pga_writeable().

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-08-09 05:00:34 +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
Alan Cox
dd05fa1945 Add a page size field to struct vm_page. Increase the page size field when
a partially populated reservation becomes fully populated, and decrease this
field when a fully populated reservation becomes partially populated.

Use this field to simplify the implementation of pmap_enter_object() on
amd64, arm, and i386.

On all architectures where we support superpages, the cost of creating a
superpage mapping is roughly the same as creating a base page mapping.  For
example, both kinds of mappings entail the creation of a single PTE and PV
entry.  With this in mind, use the page size field to make the
implementation of vm_map_pmap_enter(..., MAP_PREFAULT_PARTIAL) a little
smarter.  Previously, if MAP_PREFAULT_PARTIAL was specified to
vm_map_pmap_enter(), that function would only map base pages.  Now, it will
create up to 96 base page or superpage mappings.

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2014-06-07 17:12:26 +00:00
Alan Cox
000fb817d8 Since the introduction of the popmap to reservations in r259999, there is
no longer any need for the page's PG_CACHED and PG_FREE flags to be set and
cleared while the free page queues lock is held.  Thus, vm_page_alloc(),
vm_page_alloc_contig(), and vm_page_alloc_freelist() can wait until after
the free page queues lock is released to clear the page's flags.  Moreover,
the PG_FREE flag can be retired.  Now that the reservation system no longer
uses it, its only uses are in a few assertions.  Eliminating these
assertions is no real loss.  Other assertions catch the same types of
misbehavior, like doubly freeing a page (see r260032) or dirtying a free
page (free pages are invalid and only valid pages can be dirtied).

Eliminate an unneeded variable from vm_page_alloc_contig().

Sponsored by:	EMC / Isilon Storage Division
2013-12-31 18:25:15 +00:00
Konstantin Belousov
9eab548476 PG_SLAB no longer serves a useful purpose, since m->object is no
longer abused to store pointer to slab. Remove it.

Reviewed by:    alc
Sponsored by:   The FreeBSD Foundation
Approved by:	re (hrs)
2013-09-17 07:35:26 +00:00
Konstantin Belousov
3846a82284 Remove zero-copy sockets code. It only worked for anonymous memory,
and the equivalent functionality is now provided by sendfile(2) over
posix shared memory filedescriptor.

Remove the cow member of struct vm_page, and rearrange the remaining
members.  While there, make hold_count unsigned.

Requested and reviewed by:	alc
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
Approved by:	re (delphij)
2013-09-16 06:25:54 +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
Jeff Roberson
d9e232109f Improve pageout flow control to wakeup more frequently and do less work while
maintaining better LRU of active pages.

 - Change v_free_target to include the quantity previously represented by
   v_cache_min so we don't need to add them together everywhere we use them.
 - Add a pageout_wakeup_thresh that sets the free page count trigger for
   waking the page daemon.  Set this 10% above v_free_min so we wakeup before
   any phase transitions in vm users.
 - Adjust down v_free_target now that we're willing to accept more pagedaemon
   wakeups.  This means we process fewer pages in one iteration as well,
   leading to shorter lock hold times and less overall disruption.
 - Eliminate vm_pageout_page_stats().  This was a minor variation on the
   PQ_ACTIVE segment of the normal pageout daemon.  Instead we now process
   1 / vm_pageout_update_period pages every second.  This causes us to visit
   the whole active list every 60 seconds.  Previously we would only maintain
   the active LRU when we were short on pages which would mean it could be
   woefully out of date.

Reviewed by:	alc (slight variant of this)
Discussed with:	alc, kib, jhb
Sponsored by:	EMC / Isilon Storage Division
2013-08-13 21:56:16 +00:00
Konstantin Belousov
c325e866f4 Different consumers of the struct vm_page abuse pageq member to keep
additional information, when the page is guaranteed to not belong to a
paging queue.  Usually, this results in a lot of type casts which make
reasoning about the code correctness harder.

Sometimes m->object is used instead of pageq, which could cause real
and confusing bugs if non-NULL m->object is leaked.  See r141955 and
r253140 for examples.

Change the pageq member into a union containing explicitly-typed
members.  Use them instead of type-punning or abusing m->object in x86
pmaps, uma and vm_page_alloc_contig().

Requested and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
2013-08-10 17:36:42 +00:00
John Baldwin
cdc00bf7d2 Revert the addition of VPO_BUSY and instead update vm_page_replace() to
properly unbusy the page.

Submitted by:	alc
2013-08-09 21:14:55 +00:00
David E. O'Brien
5d82a21469 Add missing 'VPO_BUSY' from r254141 to fix kernel build break. 2013-08-09 16:43:50 +00:00
Attilio Rao
e946b94934 On all the architectures, avoid to preallocate the physical memory
for nodes used in vm_radix.
On architectures supporting direct mapping, also avoid to pre-allocate
the KVA for such nodes.

In order to do so make the operations derived from vm_radix_insert()
to fail and handle all the deriving failure of those.

vm_radix-wise introduce a new function called vm_radix_replace(),
which can replace a leaf node, already present, with a new one,
and take into account the possibility, during vm_radix_insert()
allocation, that the operations on the radix trie can recurse.
This means that if operations in vm_radix_insert() recursed
vm_radix_insert() will start from scratch again.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc (older version)
Reviewed by:	jeff
Tested by:	pho, scottl
2013-08-09 11:28:55 +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
Konstantin Belousov
449c2e92c9 Split the pagequeues per NUMA domains, and split pageademon process
into threads each processing queue in a single domain.  The structure
of the pagedaemons and queues is kept intact, most of the changes come
from the need for code to find an owning page queue for given page,
calculated from the segment containing the page.

The tie between NUMA domain and pagedaemon thread/pagequeue split is
rather arbitrary, the multithreaded daemon could be allowed for the
single-domain machines, or one domain might be split into several page
domains, to further increase concurrency.

Right now, each pagedaemon thread tries to reach the global target,
precalculated at the start of the pass.  This is not optimal, since it
could cause excessive page deactivation and freeing.  The code should
be changed to re-check the global page deficit state in the loop after
some number of iterations.

The pagedaemons reach the quorum before starting the OOM, since one
thread inability to meet the target is normal for split queues.  Only
when all pagedaemons fail to produce enough reusable pages, OOM is
started by single selected thread.

Launder is modified to take into account the segments layout with
regard to the region for which cleaning is performed.

Based on the preliminary patch by jeff, sponsored by EMC / Isilon
Storage Division.

Reviewed by:	alc
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
2013-08-07 16:36:38 +00:00
Alan Cox
2051980f97 Revise the interface between vm_object_madvise() and vm_page_dontneed() so
that pointless calls to pmap_is_modified() can be easily avoided when
performing madvise(..., MADV_FREE).

Sponsored by:	EMC / Isilon Storage Division
2013-06-10 01:48:21 +00:00
Alan Cox
da38420832 Update a comment. 2013-06-04 05:44:52 +00:00
Alan Cox
b417181250 Require that the page lock is held, instead of the object lock, when
clearing the page's PGA_REFERENCED flag.  Since we are typically
manipulating the page's act_count field when we are clearing its
PGA_REFERENCED flag, the page lock is already held everywhere that we clear
the PGA_REFERENCED flag.  So, in fact, this revision only changes some
comments and an assertion.  Nonetheless, it will enable later changes to
object locking in the pageout code.

Introduce vm_page_assert_locked(), which completely hides the implementation
details of the page lock from the caller, and use it in
vm_page_aflag_clear().  (The existing vm_page_lock_assert() could not be
used in vm_page_aflag_clear().)  Over the coming weeks, I expect that we'll
either eliminate or replace the various uses of vm_page_lock_assert() with
vm_page_assert_locked().

Reviewed by:	attilio
Sponsored by:	EMC / Isilon Storage Division
2013-06-03 01:22:54 +00:00
Alan Cox
ef5ba5a31d Simplify the definition of vm_page_lock_assert(). There is no compelling
reason to inline the implementation of vm_page_lock_assert() in the
!KLD_MODULES case.  Use the same implementation for both KLD_MODULES and
!KLD_MODULES.

Reviewed by:	kib
2013-05-31 16:00:42 +00:00
Attilio Rao
a15f7df5de The per-page act_count can be made very-easily protected by the
per-page lock rather than vm_object lock, without any further overhead.
Make the formal switch.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc
Tested by:	pho
2013-04-08 20:02:27 +00:00
Attilio Rao
774d251d99 Sync back vmcontention branch into HEAD:
Replace the per-object resident and cached pages splay tree with a
path-compressed multi-digit radix trie.
Along with this, switch also the x86-specific handling of idle page
tables to using the radix trie.

This change is supposed to do the following:
- Allowing the acquisition of read locking for lookup operations of the
  resident/cached pages collections as the per-vm_page_t splay iterators
  are now removed.
- Increase the scalability of the operations on the page collections.

The radix trie does rely on the consumers locking to ensure atomicity of
its operations.  In order to avoid deadlocks the bisection nodes are
pre-allocated in the UMA zone.  This can be done safely because the
algorithm needs at maximum one new node per insert which means the
maximum number of the desired nodes is the number of available physical
frames themselves.  However, not all the times a new bisection node is
really needed.

The radix trie implements path-compression because UFS indirect blocks
can lead to several objects with a very sparse trie, increasing the number
of levels to usually scan.  It also helps in the nodes pre-fetching by
introducing the single node per-insert property.

This code is not generalized (yet) because of the possible loss of
performance by having much of the sizes in play configurable.
However, efforts to make this code more general and then reusable in
further different consumers might be really done.

The only KPI change is the removal of the function vm_page_splay() which
is now reaped.
The only KBI change, instead, is the removal of the left/right iterators
from struct vm_page, which are now reaped.

Further technical notes broken into mealpieces can be retrieved from the
svn branch:
http://svn.freebsd.org/base/user/attilio/vmcontention/

Sponsored by:	EMC / Isilon storage division
In collaboration with:	alc, jeff
Tested by:	flo, pho, jhb, davide
Tested by:	ian (arm)
Tested by:	andreast (powerpc)
2013-03-18 00:25:02 +00:00
Alan Cox
969a0af09d Update a comment to reflect the elimination of the hold queue in r242300. 2012-11-17 04:00:19 +00:00
Konstantin Belousov
43f48b65c0 Move the declaration of vm_phys_paddr_to_vm_page() from vm/vm_page.h
to vm/vm_phys.h, where it belongs.

Requested and reviewed by:	alc
MFC after:	2 weeks
2012-11-16 05:55:56 +00:00
Konstantin Belousov
962b064afe Explicitely state that M_USE_RESERVE requires M_NOWAIT, using assertion.
Reviewed by:	alc
MFC after:	2 weeks
2012-11-16 05:49:56 +00:00
Konstantin Belousov
b32ecf44bc Flip the semantic of M_NOWAIT to only require the allocation to not
sleep, and perform the page allocations with VM_ALLOC_SYSTEM
class. Previously, the allocation was also allowed to completely drain
the reserve of the free pages, being translated to VM_ALLOC_INTERRUPT
request class for vm_page_alloc() and similar functions.

Allow the caller of malloc* to request the 'deep drain' semantic by
providing M_USE_RESERVE flag, now translated to VM_ALLOC_INTERRUPT
class. Previously, it resulted in less aggressive VM_ALLOC_SYSTEM
allocation class.

Centralize the translation of the M_* malloc(9) flags in the single
inline function malloc2vm_flags().

Discussion started by:	"Sears, Steven" <Steven.Sears@netapp.com>
Reviewed by:	alc, mdf (previous version)
Tested by:	pho (previous version)
MFC after:	2 weeks
2012-11-14 20:01:40 +00:00
Alan Cox
8d22020384 Replace the single, global page queues lock with per-queue locks on the
active and inactive paging queues.

Reviewed by:	kib
2012-11-13 02:50:39 +00:00
Attilio Rao
4ceaf45de5 Rework the known mutexes to benefit about staying on their own
cache line in order to avoid manual frobbing but using
struct mtx_padalign.

The sole exception being nvme and sxfge drivers, where the author
redefined CACHE_LINE_SIZE manually, so they need to be analyzed and
dealt with separately.

Reviwed by:	jimharris, alc
2012-10-31 18:07:18 +00:00
Alan Cox
081a488159 Replace the page hold queue, PQ_HOLD, by a new page flag, PG_UNHOLDFREE,
because the queue itself serves no purpose.  When a held page is freed,
inserting the page into the hold queue has the side effect of setting the
page's "queue" field to PQ_HOLD.  Later, when the page is unheld, it will
be freed because the "queue" field is PQ_HOLD.  In other words, PQ_HOLD is
used as a flag, not a queue.  So, this change replaces it with a flag.

To accomodate the new page flag, make the page's "flags" field wider and
"oflags" field narrower.

Reviewed by:	kib
2012-10-29 06:15:04 +00:00
Alan Cox
7ecfabc7bb Move vm_page_requeue() to the only file that uses it.
MFC after:	3 weeks
2012-10-13 20:19:43 +00:00
Konstantin Belousov
b6c00483e9 Do not leave invalid pages in the object after the short read for a
network file systems (not only NFS proper). Short reads cause pages
other then the requested one, which were not filled by read response,
to stay invalid.

Change the vm_page_readahead_finish() interface to not take the error
code, but instead to make a decision to free or to (de)activate the
page only by its validity. As result, not requested invalid pages are
freed even if the read RPC indicated success.

Noted and reviewed by:	alc
MFC after:	1 week
2012-08-14 11:45:47 +00:00
Konstantin Belousov
1c771f9222 After the PHYS_TO_VM_PAGE() function was de-inlined, the main reason
to pull vm_param.h was removed.  Other big dependency of vm_page.h on
vm_param.h are PA_LOCK* definitions, which are only needed for
in-kernel code, because modules use KBI-safe functions to lock the
pages.

Stop including vm_param.h into vm_page.h. Include vm_param.h
explicitely for the kernel code which needs it.

Suggested and reviewed by:	alc
MFC after:    2 weeks
2012-08-05 14:11:42 +00:00
Konstantin Belousov
0055cbd3c5 Reduce code duplication and exposure of direct access to struct
vm_page oflags by providing helper function
vm_page_readahead_finish(), which handles completed reads for pages
with indexes other then the requested one, for VOP_GETPAGES().

Reviewed by:	alc
MFC after:	1 week
2012-08-04 18:16:43 +00:00
Alan Cox
369763e31a Inline vm_page_aflags_clear() and vm_page_aflags_set().
Add comments stating that neither these functions nor the flags that they
are used to manipulate are part of the KBI.
2012-08-03 01:48:15 +00:00
Alan Cox
d26a90a8b2 Eliminate an unneeded declaration. (I should have removed this as part
of r227568.)
2012-07-30 20:38:37 +00:00
Alan Cox
eddc92918e Selectively inline vm_page_dirty(). 2012-06-20 23:25:47 +00:00
Alan Cox
6031c68de4 The page flag PGA_WRITEABLE is set and cleared exclusively by the pmap
layer, but it is read directly by the MI VM layer.  This change introduces
pmap_page_is_write_mapped() in order to completely encapsulate all direct
access to PGA_WRITEABLE in the pmap layer.

Aesthetics aside, I am making this change because amd64 will likely begin
using an alternative method to track write mappings, and having
pmap_page_is_write_mapped() in place allows me to make such a change
without further modification to the MI VM layer.

As an added bonus, tidy up some nearby comments concerning page flags.

Reviewed by:	kib
MFC after:	6 weeks
2012-06-16 18:56:19 +00:00
Konstantin Belousov
b6de32bd9b Add a facility to register a range of physical addresses to be used
for allocation of fictitious pages, for which PHYS_TO_VM_PAGE()
returns proper fictitious vm_page_t. The range should be de-registered
after consumer stopped using it.

De-inline the PHYS_TO_VM_PAGE() since it now carries code to iterate
over registered ranges.

A hash container might be developed instead of range registration
interface, and fake pages could be put automatically into the hash,
were PHYS_TO_VM_PAGE() could look them up later. This should be
considered before the MFC of the commit is done.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
MFC after:	1 month
2012-05-12 20:42:56 +00:00
Konstantin Belousov
e461aae747 Split the code from vm_page_getfake() to initialize the fake page struct
vm_page into new interface vm_page_initfake(). Handle the case of fake
page re-initialization with changed memattr.

Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
MFC after:	1 month
2012-05-12 20:34:22 +00:00
Konstantin Belousov
13a0b7bcc4 Commit the change forgotten in r235356.
Sponsored by:	The FreeBSD Foundation
Reviewed by:	alc
MFC after:	1 month
2012-05-12 20:10:18 +00:00
Alan Cox
1c8279e4e7 Fix mincore(2) so that it reports PG_CACHED pages as resident.
MFC after:	2 weeks
2012-04-08 18:25:12 +00:00
Attilio Rao
d1aa86e151 Staticize vm_page_cache_remove().
Reviewed by:	alc
2012-04-06 20:34:00 +00:00
Nathan Whitehorn
57bd5cce62 Reduce the frequency that the PowerPC/AIM pmaps invalidate instruction
caches, by invalidating kernel icaches only when needed and not flushing
user caches for shared pages.

Suggested by:	kib
MFC after:	2 weeks
2012-04-06 16:03:38 +00:00
Kip Macy
263811f724 exclude kmem_alloc'ed ARC data buffers from kernel minidumps on amd64
excluding other allocations including UMA now entails the addition of
a single flag to kmem_alloc or uma zone create

Reviewed by:	alc, avg
MFC after:	2 weeks
2012-01-27 20:18:31 +00:00
Konstantin Belousov
dc874f9881 Rename vm_page_set_valid() to vm_page_set_valid_range().
The vm_page_set_valid() is the most reasonable name for the m->valid
accessor.

Reviewed by:	attilio, alc
2011-11-30 17:39:00 +00:00
Konstantin Belousov
cf1911a9ad Hide the internals of vm_page_lock(9) from the loadable modules.
Since the address of vm_page lock mutex depends on the kernel options,
it is easy for module to get out of sync with the kernel.

No vm_page_lockptr() accessor is provided for modules. It can be added
later if needed, unless proper KPI is developed to serve the needs.

Reviewed by:	attilio, alc
MFC after:	3 weeks
2011-11-29 13:07:32 +00:00
Alan Cox
fbd80bd047 Refactor the code that performs physically contiguous memory allocation,
yielding a new public interface, vm_page_alloc_contig().  This new function
addresses some of the limitations of the current interfaces, contigmalloc()
and kmem_alloc_contig().  For example, the physically contiguous memory that
is allocated with those interfaces can only be allocated to the kernel vm
object and must be mapped into the kernel virtual address space.  It also
provides functionality that vm_phys_alloc_contig() doesn't, such as wiring
the returned pages.  Moreover, unlike that function, it respects the low
water marks on the paging queues and wakes up the page daemon when
necessary.  That said, at present, this new function can't be applied to all
types of vm objects.  However, that restriction will be eliminated in the
coming weeks.

From a design standpoint, this change also addresses an inconsistency
between vm_phys_alloc_contig() and the other vm_phys_alloc*() functions.
Specifically, vm_phys_alloc_contig() manipulated vm_page fields that other
functions in vm/vm_phys.c didn't.  Moreover, vm_phys_alloc_contig() knew
about vnodes and reservations.  Now, vm_page_alloc_contig() is responsible
for these things.

Reviewed by:	kib
Discussed with:	jhb
2011-11-16 16:46:09 +00:00
Konstantin Belousov
7845becfe8 Remove redundand definitions. The chunk was missed from r227102.
MFC after:	2 weeks
2011-11-05 09:03:18 +00:00
Konstantin Belousov
561cc9fcb5 Provide typedefs for the type of bit mask for the page bits.
Use the defined types instead of int when manipulating masks.
Supposedly, it could fix support for 32KB page size in the
machine-independend VM layer.

Reviewed by:	alc
MFC after:	2 weeks
2011-11-05 08:20:32 +00:00