Rather than not redirting the bp when we get ENXIO, only redirty it
when the error is EIO. This catches a much larger class of errors
that are unlikely to succeed if retried.

Submitted by: bde

A partial solution to some of the 'pull the umass device with a
mounted FS' problems. These are more along the lines of 'avoiding an
avoidable panic' than a complete solution to removable devices.

A partial solution to some of the 'pull the umass device with a
mounted FS' problems. These are more along the lines of 'avoiding an
avoidable panic' than a complete solution to removable devices. We
now close the barn door after the horse has gotten lose and has been
hit by a truck, as it were. The barn no longer catches fire in this
case, but the horse is still dead :-).

The vfs_bio.c fix causes us not to put a failed write back into the
dirty pool if the error returned was ENXIO. In that case, the buffer
is treated like any other clean buffer that's being retured. ENXIO
means the device isn't there anymore and will never be there again in
the future, so retrying is futile.

The vfs_mount.c fix treats 'ENXIO' as success for unmounting a file
system. If the device is gone, retrying later won't help and we'll
never be able to unmount the device.

These two are part of a larger patch set submitted by the author. The
other patches will be forth coming. I added comments to these two
patches.

Submitted by: Henrik Gulbrandsen
Reviewed by: phk@
PR: usb/46176 (partial)

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Eliminate vfs_page_set_valid()'s unused argument.

Rename the kthread_xxx (e.g. kthread_create()) calls
to kproc_xxx as they actually make whole processes.
Thos makes way for us to add REAL kthread_create() and friends
that actually make theads. it t

Rename the kthread_xxx (e.g. kthread_create()) calls
to kproc_xxx as they actually make whole processes.
Thos makes way for us to add REAL kthread_create() and friends
that actually make theads. it turns out that most of these
calls actually end up being moved back to the thread version
when it's added. but we need to make this cosmetic change first.

I'd LOVE to do this rename in 7.0 so that we can eventually MFC the
new kthread_xxx() calls.

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Fix the description of the formula used to autosize the number of
buffers in the buffer cache.

Approved by: re (kensmith)

Change the management of cached pages (PQ_CACHE) in two fundamental
ways:

(1) Cached pages are no longer kept in the object's resident page
splay tree and memq. Instead, they are kept in a separate

Change the management of cached pages (PQ_CACHE) in two fundamental
ways:

(1) Cached pages are no longer kept in the object's resident page
splay tree and memq. Instead, they are kept in a separate per-object
splay tree of cached pages. However, access to this new per-object
splay tree is synchronized by the _free_ page queues lock, not to be
confused with the heavily contended page queues lock. Consequently, a
cached page can be reclaimed by vm_page_alloc(9) without acquiring the
object's lock or the page queues lock.

This solves a problem independently reported by tegge@ and Isilon.
Specifically, they observed the page daemon consuming a great deal of
CPU time because of pages bouncing back and forth between the cache
queue (PQ_CACHE) and the inactive queue (PQ_INACTIVE). The source of
this problem turned out to be a deadlock avoidance strategy employed
when selecting a cached page to reclaim in vm_page_select_cache().
However, the root cause was really that reclaiming a cached page
required the acquisition of an object lock while the page queues lock
was already held. Thus, this change addresses the problem at its
root, by eliminating the need to acquire the object's lock.

Moreover, keeping cached pages in the object's primary splay tree and
memq was, in effect, optimizing for the uncommon case. Cached pages
are reclaimed far, far more often than they are reactivated. Instead,
this change makes reclamation cheaper, especially in terms of
synchronization overhead, and reactivation more expensive, because
reactivated pages will have to be reentered into the object's primary
splay tree and memq.

(2) Cached pages are now stored alongside free pages in the physical
memory allocator's buddy queues, increasing the likelihood that large
allocations of contiguous physical memory (i.e., superpages) will
succeed.

Finally, as a result of this change long-standing restrictions on when
and where a cached page can be reclaimed and returned by
vm_page_alloc(9) are eliminated. Specifically, calls to
vm_page_alloc(9) specifying VM_ALLOC_INTERRUPT can now reclaim and
return a formerly cached page. Consequently, a call to malloc(9)
specifying M_NOWAIT is less likely to fail.

Discussed with: many over the course of the summer, including jeff@,
Justin Husted @ Isilon, peter@, tegge@
Tested by: an earlier version by kris@
Approved by: re (kensmith)

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Work around an integer overflow in expression `3 * maxbufspace / 4',
when maxbufspace is larger than INT_MAX / 3. The overflow causes a
hard hang on ia64 when physical memory is sufficiently large (8

Work around an integer overflow in expression `3 * maxbufspace / 4',
when maxbufspace is larger than INT_MAX / 3. The overflow causes a
hard hang on ia64 when physical memory is sufficiently large (8GB).

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In getblk(), before gbincore(), use BO_LOCK directly when locking
the bufobj, rather than using VI_LOCK, like what was done with
revision 1.453.

- 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

- 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)

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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 b

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)

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- 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 sc

- 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>

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Disable nesting of BOP_BDFLUSH(). VOP_FSYNC() call in bdwrite() could
result in bdwrite() being reentered, thus causing infinite recursion.

Reported and tested by: Peter Holm
Reviewed by: tegge
MFC

Disable nesting of BOP_BDFLUSH(). VOP_FSYNC() call in bdwrite() could
result in bdwrite() being reentered, thus causing infinite recursion.

Reported and tested by: Peter Holm
Reviewed by: tegge
MFC after: 2 weeks

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vm_map_delete should be used only internally, by the VM subsystem. Replace
it with vm_map_remove, which not only embeds additional check, but also
takes care of locking.

Reviewed by: alc
Approved by

vm_map_delete should be used only internally, by the VM subsystem. Replace
it with vm_map_remove, which not only embeds additional check, but also
takes care of locking.

Reviewed by: alc
Approved by: alc, cognet (mentor)

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Correct a comment typo

Instead of doing comparisons using the pcpu area to see if
a thread is an idle thread, just see if it has the IDLETD
flag set. That flag will probably move to the pflags word
as it's permenent and ne

Instead of doing comparisons using the pcpu area to see if
a thread is an idle thread, just see if it has the IDLETD
flag set. That flag will probably move to the pflags word
as it's permenent and never chenges for the life of the
system so it doesn't need locking.

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Use LIST_EMPTY() instead of unrolled version (LIST_FIRST() [!=]= NULL)

Cylinder group bitmaps and blocks containing inode for a snapshot
file are after snaplock, while other ffs device buffers are before
snaplock in global lock order. By itself, this could cause deadloc

Cylinder group bitmaps and blocks containing inode for a snapshot
file are after snaplock, while other ffs device buffers are before
snaplock in global lock order. By itself, this could cause deadlock
when bdwrite() tries to flush dirty buffers on snapshotted ffs. If,
during the flush, COW activity for snapshot needs to allocate block
and ffs_alloccg() selects the cylinder group that is being written
by bdwrite(), then kernel would panic due to recursive buffer lock
acquision.

Avoid dealing with buffers in bdwrite() that are from other side of
snaplock divisor in the lock order then the buffer being written. Add
new BOP, bop_bdwrite(), to do dirty buffer flushing for same vnode in
the bdwrite(). Default implementation, bufbdflush(), refactors the code
from bdwrite(). For ffs device buffers, specialized implementation is
used.

Reviewed by: tegge, jeff, Russell Cattelan (cattelan xfs org, xfs changes)
Tested by: Peter Holm
X-MFC after: 3 weeks (if ever: it changes ABI)

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In rev. 1.514, iodone on async buffer may happen before code checks the
vnode v_flag. For cluster buffers this would result in dereferencing NULL
b_vp. To prevent the panic, cache relevant vnode flag

In rev. 1.514, iodone on async buffer may happen before code checks the
vnode v_flag. For cluster buffers this would result in dereferencing NULL
b_vp. To prevent the panic, cache relevant vnode flag before calling
bstrategy.

Reported by: Peter Holm, kris
Tested by: Peter Holm
Reviewed by: tegge
Pointy hat to: kib

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Resolve two deadlocks that could be caused by busy md device backed
by vnode. Allow for md thread and the thread that owns lock on vnode
backing the md device to do the write even when runningbufspac

Resolve two deadlocks that could be caused by busy md device backed
by vnode. Allow for md thread and the thread that owns lock on vnode
backing the md device to do the write even when runningbufspace is
exhausted.

Tested by: Peter Holm
Reviewed by: tegge
MFC after: 2 weeks

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Refactor vfs_setdirty(), creating vfs_setdirty_locked_object().

Call vfs_setdirty_locked_object() from vfs_busy_pages() instead of
vfs_setdirty(), thereby eliminating a second acquisition and releas

Refactor vfs_setdirty(), creating vfs_setdirty_locked_object().

Call vfs_setdirty_locked_object() from vfs_busy_pages() instead of
vfs_setdirty(), thereby eliminating a second acquisition and release
of the same vm object lock.

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In bufdone_finish() restrict the acquisition and release of the page
queues lock to BIO_READ operations. Recent changes to the implementation
of the per-page flags have eliminated the need for the p

In bufdone_finish() restrict the acquisition and release of the page
queues lock to BIO_READ operations. Recent changes to the implementation
of the per-page flags have eliminated the need for the page queues lock
in the other cases.

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Replace PG_BUSY with VPO_BUSY. In other words, changes to the page's
busy flag, i.e., VPO_BUSY, are now synchronized by the per-vm object
lock instead of the global page queues lock.

If the buffer lock has waiters after the buffer has changed identity then
getnewbuf() needs to drop the buffer in order to wake waiters that might
sleep on the buffer in the context of the old identi

If the buffer lock has waiters after the buffer has changed identity then
getnewbuf() needs to drop the buffer in order to wake waiters that might
sleep on the buffer in the context of the old identity.

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Introduce a field to struct vm_page for storing flags that are
synchronized by the lock on the object containing the page.

Transition PG_WANTED and PG_SWAPINPROG to use the new field,
eliminating th

Introduce a field to struct vm_page for storing flags that are
synchronized by the lock on the object containing the page.

Transition PG_WANTED and PG_SWAPINPROG to use the new field,
eliminating the need for holding the page queues lock when setting
or clearing these flags. Rename PG_WANTED and PG_SWAPINPROG to
VPO_WANTED and VPO_SWAPINPROG, respectively.

Eliminate the assertion that the page queues lock is held in
vm_page_io_finish().

Eliminate the acquisition and release of the page queues lock
around calls to vm_page_io_finish() in kern_sendfile() and
vfs_unbusy_pages().

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Reduce the scope of the page queues lock in vfs_busy_pages() now that
vm_page_sleep_if_busy() no longer requires the caller to hold the page
queues lock.