Commit Graph

267 Commits

Author SHA1 Message Date
Warner Losh
60727d8b86 /* -> /*- for license, minor formatting changes 2005-01-07 02:29:27 +00:00
Alan Cox
df2e33bf42 Revise the part of vm_pageout_scan() that moves pages from the cache
queue to the free queue.  With this change, if a page from the cache
queue belongs to a locked object, it is simply skipped over rather
than moved to the inactive queue.
2005-01-06 20:22:36 +00:00
Alan Cox
34d9e6fdae During traversal of the inactive queue, try locking the page's containing
object before accessing the page's flags or the object's reference count.
2004-11-05 06:24:05 +00:00
Alan Cox
d19ef81437 The synchronization provided by vm object locking has eliminated the
need for most calls to vm_page_busy().  Specifically, most calls to
vm_page_busy() occur immediately prior to a call to vm_page_remove().
In such cases, the containing vm object is locked across both calls.
Consequently, the setting of the vm page's PG_BUSY flag is not even
visible to other threads that are following the synchronization
protocol.

This change (1) eliminates the calls to vm_page_busy() that
immediately precede a call to vm_page_remove() or functions, such as
vm_page_free() and vm_page_rename(), that call it and (2) relaxes the
requirement in vm_page_remove() that the vm page's PG_BUSY flag is
set.  Now, the vm page's PG_BUSY flag is set only when the vm object
lock is released while the vm page is still in transition.  Typically,
this is when it is undergoing I/O.
2004-11-03 20:17:31 +00:00
Alan Cox
b86e6ec007 During traversal of the active queue by vm_pageout_page_stats(), try
locking the page's containing object before accessing the page's flags.
2004-10-30 23:30:53 +00:00
Alan Cox
4b8a5c4095 Add an assignment statement that I omitted from the previous revision. 2004-10-30 07:09:46 +00:00
Alan Cox
b08abf6cc0 During traversal of the active queue, try locking the page's containing
object before accessing the page's flags or the object's reference count.
If the trylock fails, handle the page as though it is busy.
2004-10-27 18:29:17 +00:00
Alan Cox
3e36afbe27 Remove the GIANT_REQUIRED preceding pmap_remove() in
vm_pageout_map_deactivate_pages().
2004-07-18 04:38:11 +00:00
Alan Cox
3d2e54c317 Push down the acquisition and release of the page queues lock into
pmap_protect() and pmap_remove().  In general, they require the lock in
order to modify a page's pv list or flags.  In some cases, however,
pmap_protect() can avoid acquiring the lock.
2004-07-15 18:00:43 +00:00
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
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
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
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
Bruce Evans
dcbcd518e0 Minor style fixes. In vm_daemon(), don't fetch the rss limit long before
it is needed.
2004-03-04 09:36:46 +00:00
Alan Cox
9ea8d1a67c Eliminate the second, unnecessary call to pmap_page_protect() near the end
of vm_pageout_flush().  Instead, assert that the page is still write
protected.

Discussed with:	tegge
2004-02-21 23:32:00 +00:00
Alan Cox
84d98bf699 - Correct a long-standing race condition in vm_page_try_to_cache() that
could result in a panic "vm_page_cache: caching a dirty page, ...":
   Access to the page must be restricted or removed before calling
   vm_page_cache().  This race condition is identical in nature to that
   which was addressed by vm_pageout.c's revision 1.251.
 - Simplify the code surrounding the fix to this same race condition
   in vm_pageout.c's revision 1.251.  There should be no behavioral
   change.  Reviewed by: tegge

MFC after:	7 days
2004-02-14 08:54:37 +00:00
Alan Cox
a3dfacb51c Correct a long-standing race condition in the inactive queue scan. (See
the added comment for low-level details.)  The effect of this race
condition is a panic "vm_page_cache: caching a dirty page, ..."

Reviewed by:	tegge
MFC after:	7 days
2004-02-10 18:34:27 +00:00
John Baldwin
91d5354a2c Locking for the per-process resource limits structure.
- struct plimit includes a mutex to protect a reference count.  The plimit
  structure is treated similarly to struct ucred in that is is always copy
  on write, so having a reference to a structure is sufficient to read from
  it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
  limits from a process to keep the limit structure from changing out from
  under you while reading from it.
- Various global limits that are ints are not protected by a lock since
  int writes are atomic on all the archs we support and thus a lock
  wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
  behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
  either an rlimit, or the current or max individual limit of the specified
  resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
  other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
  (it didn't used the stackgap when it should have) but uses lim_rlimit()
  and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
  but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits.  It
  also no longer uses the stackgap for accessing sysctl's for the
  ibcs2_sysconf() syscall but uses kernel_sysctl() instead.  As a result,
  ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.

Submitted by:	mtm (mostly, I only did a few cleanups and catchups)
Tested on:	i386
Compiled on:	alpha, amd64
2004-02-04 21:52:57 +00:00
Alan Cox
2e3b314d3a - Push down Giant from vm_pageout() to vm_pageout_scan(), freeing
vm_pageout_page_stats() from Giant.
 - Modify vm_pager_put_pages() and vm_pager_page_unswapped() to expect the
   vm object to be locked on entry.  (All of the pager routines now expect
   this.)
2003-10-24 06:43:04 +00:00
Alan Cox
ab42316c2f - Retire vm_pageout_page_free(). Instead, use vm_page_select_cache() from
vm_pageout_scan().  Rationale: I don't like leaving a busy page in the
   cache queue with neither the vm object nor the vm page queues lock held.
 - Assert that the page is active in vm_pageout_page_stats().
2003-10-22 18:41:32 +00:00
Alan Cox
d3c09dd7db - Assert that every page found in the active queue is an active page. 2003-10-22 03:08:24 +00:00
Alan Cox
7a93508274 - Increase the object lock's scope in vm_contig_launder() so that access
to the object's type field and the call to vm_pageout_flush() are
   synchronized.
 - The above change allows for the eliminaton of the last parameter
   to vm_pageout_flush().
 - Synchronize access to the page's valid field in vm_pageout_flush()
   using the containing object's lock.
2003-10-18 21:09:21 +00:00
Alan Cox
6989c456b3 - Synchronize access to a vm page's valid field using the containing
vm object's lock.
 - Release the vm object and vm page queues locks around vput().
2003-10-17 05:07:17 +00:00
Alan Cox
45ae1d9147 Merge vm_pageout_free_page_calc() into vm_pageout(), eliminating some
unneeded code.
2003-09-19 05:03:45 +00:00
Alan Cox
4b5f553179 When calling vget() on a vnode-backed vm object, acquire the vnode
interlock before releasing the vm object's lock.
2003-09-17 06:55:42 +00:00
Alan Cox
3562af1215 - Add vm object locking to the part of vm_pageout_scan() that launders
dirty pages.
 - Remove some unused variables.
2003-08-31 00:00:46 +00:00
Alan Cox
3e1b578a28 Extend the scope of the page queues lock in vm_pageout_scan() to cover
the traversal of the PQ_INACTIVE queue.
2003-08-15 05:13:36 +00:00
Poul-Henning Kamp
8f60c087e6 Change the layout policy of the swap_pager from a hardcoded width
striping to a per device round-robin algorithm.

Because of the policy of not attempting to retain previous swap
allocation on page-out, this means that a newly added swap device
almost instantly takes its 1/N share of the I/O load but it takes
somewhat longer for it to assume it's 1/N share of the pages if there
is plenty of space on the other devices.

Change the 8G total swapspace limitation to 8G per device instead
by using a per device blist rather than one global blist.  This
reduces the memory footprint by 75% (typically a couple hundred
kilobytes) for the common case with one swapdevice but NSWAPDEV=4.

Remove the compile time constant limit of number of swap devices,
there is no limit now.  Instead of a fixed size array, store the
per swapdev structure in a TAILQ.

Total swap space is still addressed by a 32 bit page number and
therefore the upper limit is now 2^42 bytes = 16TB (for i386).

We still do not allocate the first page of each device in order to
give some amount of protection to any bsdlabel at the start of the
device.

A new device is appended after the existing devices in the swap space,
no attempt is made to fill in holes left behind by swapoff (this can
trivially be changed should it ever become a problem).

The sysctl vm.nswapdev now reflects the number of currently configured
swap devices.

Rename vm_swap_size to swap_pager_avail for consistency with other
exported names.

Change argument type for vm_proc_swapin_all() and swap_pager_isswapped()
to be a struct swdevt pointer rather than an index.

Not changed: we are still using blists to manage the free space,
but since the swapspace is no longer fragmented by the striping
different resource managers might fare better.
2003-08-03 13:35:31 +00:00
Alan Cox
ecf6279f00 - Complete the vm object locking in vm_pageout_object_deactivate_pages().
- Change vm_pageout_object_deactivate_pages()'s first parameter from a
   vm_map_t to a pmap_t.
 - Change vm_pageout_object_deactivate_pages()'s and
   vm_pageout_map_deactivate_pages()'s last parameter from a vm_pindex_t
   to a long.  Since the number of pages in an address space doesn't
   require 64 bits on an i386, vm_pindex_t is overkill.
2003-07-07 07:16:29 +00:00
Alan Cox
0774dfb376 Add vm object locking to vm_pageout_map_deactivate_pages(). 2003-06-29 19:51:24 +00:00
Alan Cox
5163584c7e - Add vm object locking to vm_pageout_clean(). 2003-06-28 20:07:54 +00:00
David E. O'Brien
874651b13c Use __FBSDID(). 2003-06-11 23:50:51 +00:00
David Schultz
e92686d065 If we seem to be out of VM, don't allow the pagedaemon to kill
processes in the first pass.  Among other things, this will give
us a chance to launder vnode-backed pages before concluding that
we need more swap.  This is particularly useful for systems that
have no swap.

While here, update a comment and remove some long-unused code.

Reported by:	Lucky Green <shamrock@cypherpunks.to>
Suggested by:	dillon
Approved by:	re (rwatson)
2003-05-19 00:51:07 +00:00
Alan Cox
c4a1d732a3 Avoid a lock-order reversal and implement vm_object locking
in vm_pageout_page_free().
2003-05-04 06:56:27 +00:00
Alan Cox
85b1dc89b6 Eliminate an unused parameter from vm_pageout_object_deactivate_pages(). 2003-04-30 03:08:16 +00:00
Alan Cox
b6e48e0372 - Acquire the vm_object's lock when performing vm_object_page_clean().
- Add a parameter to vm_pageout_flush() that tells vm_pageout_flush()
   whether its caller has locked the vm_object.  (This is a temporary
   measure to bootstrap vm_object locking.)
2003-04-24 04:31:25 +00:00
John Baldwin
897ecacd64 Lock the proc to check p_flag and several other related tests in
vm_daemon().  We don't need to hold sched_lock as long now as a result.
2003-04-22 20:03:08 +00:00
Alan Cox
72ba747d16 - Lock the vm_object when performing vm_object_pip_wakeup().
- Merge two identical cases in a switch statement.
2003-04-20 20:37:14 +00:00
Alan Cox
d22bc7101c - Lock the vm_object when performing vm_object_pip_add(). 2003-04-20 03:41:21 +00:00
Wes Peters
f4cf2141f6 Add a facility allowing processes to inform the VM subsystem they are
critical and should not be killed when pageout is looking for more
memory pages in all the wrong places.

Reviewed by:	arch@
Sponsored by:	St. Bernard Software
2003-03-31 21:09:57 +00:00
David Schultz
72d97679ff - When the VM daemon is out of swap space and looking for a
process to kill, don't block on a map lock while holding the
  process lock.  Instead, skip processes whose map locks are held
  and find something else to kill.
- Add vm_map_trylock_read() to support the above.

Reviewed by:	alc, mike (mentor)
2003-03-12 23:13:16 +00:00
Alan Cox
6b4b77ad34 Add a comment describing how pagedaemon_wakeup() should be used and
synchronized.

Suggested by:	tegge
2003-02-09 20:40:36 +00:00
Alan Cox
a1c0a78518 - It's more accurate to say that vm_paging_needed() returns TRUE
than a positive number.
 - In pagedaemon_wakeup(), set vm_pages_needed to 1 rather than
   incrementing it to accomplish the same.
2003-02-02 07:16:40 +00:00
Alan Cox
8e1d8de578 - Convert vm_pageout()'s tsleep()s to msleep()s with the page queue lock. 2003-02-02 01:11:21 +00:00
Alan Cox
8b24576748 - Remove (some) unnecessary explicit initializations to zero.
- Style changes to vm_pageout(): declarations and white-space.
2003-02-01 21:55:30 +00:00
Alan Cox
b0ef8c5fe4 - Update vm_pageout_deficit using atomic operations. It's a simple
counter outside the scope of existing locks.
 - Eliminate a redundant clearing of vm_pageout_deficit.
2003-01-14 06:57:03 +00:00
Alan Cox
ff2023a5df Make vm_pageout_page_free() static. 2003-01-14 02:28:39 +00:00
Poul-Henning Kamp
c410df597b Avoid extern decls in .c files by putting them in the vm/swap_pager.h
include file where they belong.
Share the dmmax_mask variable.
2003-01-03 14:30:46 +00:00
Matthew Dillon
40bb4f4bcf vm_pager_put_pages() takes VM_PAGER_* flags, not OBJPC_* flags. It just
so happens that OBJPC_SYNC has the same value as VM_PAGER_PUT_SYNC so no
harm done.  But fix it :-)

No operational changes.

MFC after:	1 day
2002-12-28 21:15:39 +00:00