Remove sysctl vm.max_proc_mmap used to protect from KVA space exhaustion.
As it was pointed out by Alan Cox, that no longer serves its purpose with
the modern UMA allocator compared to the old one us

Remove sysctl vm.max_proc_mmap used to protect from KVA space exhaustion.
As it was pointed out by Alan Cox, that no longer serves its purpose with
the modern UMA allocator compared to the old one used in 4.x days.

The removal of sysctl eliminates max_proc_mmap type overflow leading to
the broken mmap(2) seen with large amount of physical memory on arches
with factually unbound KVA space (such as amd64). It was found that
slightly less than 256GB of physmem was enough to trigger the overflow.

Reviewed by: alc, kib
Approved by: avg (mentor)
MFC after: 2 months

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Sync: merge r216133 through r216338 from ^/head.

svn+ssh://svn.freebsd.org/base/head@216199

Fix comment intentation.

Sync: merge r215319 through r215395 from ^/head, so ports can actually
build! :)

Do not use __FreeBSD_version prefix for the special osrel version.
The ports/Mk/bsd.port.mk uses sys/param.h to fetch osrel, and cannot
grok several constants with the prefix.

Reported and tested by

Do not use __FreeBSD_version prefix for the special osrel version.
The ports/Mk/bsd.port.mk uses sys/param.h to fetch osrel, and cannot
grok several constants with the prefix.

Reported and tested by: swell.k gmail com
MFC after: 1 week

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Sync: merge r215273 through r215318 from ^/head.

Use symbolic names instead of hardcoding values for magic p_osrel constants.

MFC after: 1 week

Merge svn+ssh://svn.freebsd.org/base/head@214309

Allow a POSIX shared memory object that is opened for read but not for
write to nonetheless be mapped PROT_WRITE and MAP_PRIVATE, i.e.,
copy-on-write.

(This is a regression in the new implementation

Allow a POSIX shared memory object that is opened for read but not for
write to nonetheless be mapped PROT_WRITE and MAP_PRIVATE, i.e.,
copy-on-write.

(This is a regression in the new implementation of POSIX shared memory
objects that is used by HEAD and RELENG_8. This bug does not exist in
RELENG_7's user-level, file-based implementation.)

PR: 150260
MFC after: 3 weeks

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Fix a typo in r212281. uintptr -> uintptr_t

Pointy hat to: rstone

Approved by: emaste (mentor)
MFC after: 2 weeks

In munmap() downgrade the vm_map_lock to a read lock before taking a read
lock on the pmc-sx lock. This prevents a deadlock with
pmc_log_process_mappings, which has an exclusive lock on pmc-sx and t

In munmap() downgrade the vm_map_lock to a read lock before taking a read
lock on the pmc-sx lock. This prevents a deadlock with
pmc_log_process_mappings, which has an exclusive lock on pmc-sx and tries
to get a read lock on a vm_map. Downgrading the vm_map_lock in munmap
allows pmc_log_process_mappings to continue, preventing the deadlock.

Without this change I could cause a deadlock on a multicore 8.1-RELEASE
system by having one thread constantly mmap'ing and then munmap'ing a
PROT_EXEC mapping in a loop while I repeatedly invoked and stopped pmcstat
in system-wide sampling mode.

Reviewed by: fabient
Approved by: emaste (mentor)
MFC after: 2 weeks

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Add the MAP_PREFAULT_READ option to mmap(2).

Reviewed by: jhb, kib

Merge svn+ssh://svn.freebsd.org/base/head@211344

Add new make_dev_p(9) flag MAKEDEV_ETERNAL to inform devfs that created
cdev will never be destroyed. Propagate the flag to devfs vnodes as
VV_ETERNVALDEV. Use the flags to avoid acquiring devmtx and

Add new make_dev_p(9) flag MAKEDEV_ETERNAL to inform devfs that created
cdev will never be destroyed. Propagate the flag to devfs vnodes as
VV_ETERNVALDEV. Use the flags to avoid acquiring devmtx and taking a
thread reference on such nodes.

In collaboration with: pho
MFC after: 1 month

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Fix commented out resource limit check in mlockall(2). It's still racy,
but at least less misleading.

Merge svn+ssh://svn.freebsd.org/base/head@208879

Push down page queues lock acquisition in pmap_enter_object() and
pmap_is_referenced(). Eliminate the corresponding page queues lock
acquisitions from vm_map_pmap_enter() and mincore(), respectively

Push down page queues lock acquisition in pmap_enter_object() and
pmap_is_referenced(). Eliminate the corresponding page queues lock
acquisitions from vm_map_pmap_enter() and mincore(), respectively. In
mincore(), this allows some additional cases to complete without ever
acquiring the page queues lock.

Assert that the page is managed in pmap_is_referenced().

On powerpc/aim, push down the page queues lock acquisition from
moea*_is_modified() and moea*_is_referenced() into moea*_query_bit().
Again, this will allow some additional cases to complete without ever
acquiring the page queues lock.

Reorder a few statements in vm_page_dontneed() so that a race can't lead
to an old reference persisting. This scenario is described in detail by a
comment.

Correct a spelling error in vm_page_dontneed().

Assert that the object is locked in vm_page_clear_dirty(), and restrict the
page queues lock assertion to just those cases in which the page is
currently writeable.

Add object locking to vnode_pager_generic_putpages(). This was the one
and only place where vm_page_clear_dirty() was being called without the
object being locked.

Eliminate an unnecessary vm_page_lock() around vnode_pager_setsize()'s call
to vm_page_clear_dirty().

Change vnode_pager_generic_putpages() to the modern-style of function
definition. Also, change the name of one of the parameters to follow
virtual memory system naming conventions.

Reviewed by: kib

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Merge svn+ssh://svn.freebsd.org/base/head@208557

Roughly half of a typical pmap_mincore() implementation is machine-
independent code. Move this code into mincore(), and eliminate the
page queues lock from pmap_mincore().

Push down the page queue

Roughly half of a typical pmap_mincore() implementation is machine-
independent code. Move this code into mincore(), and eliminate the
page queues lock from pmap_mincore().

Push down the page queues lock into pmap_clear_modify(),
pmap_clear_reference(), and pmap_is_modified(). Assert that these
functions are never passed an unmanaged page.

Eliminate an inaccurate comment from powerpc/powerpc/mmu_if.m:
Contrary to what the comment says, pmap_mincore() is not simply an
optimization. Without a complete pmap_mincore() implementation,
mincore() cannot return either MINCORE_MODIFIED or MINCORE_REFERENCED
because only the pmap can provide this information.

Eliminate the page queues lock from vfs_setdirty_locked_object(),
vm_pageout_clean(), vm_object_page_collect_flush(), and
vm_object_page_clean(). Generally speaking, these are all accesses
to the page's dirty field, which are synchronized by the containing
vm object's lock.

Reduce the scope of the page queues lock in vm_object_madvise() and
vm_page_dontneed().

Reviewed by: kib (an earlier version)

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Merge svn+ssh://svn.freebsd.org/base/head@207793

Final update to current version of head in preparation for reintegration.

On Alan's advice, rather than do a wholesale conversion on a single
architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
s

On Alan's advice, rather than do a wholesale conversion on a single
architecture from page queue lock to a hashed array of page locks
(based on a patch by Jeff Roberson), I've implemented page lock
support in the MI code and have only moved vm_page's hold_count
out from under page queue mutex to page lock. This changes
pmap_extract_and_hold on all pmaps.

Supported by: Bitgravity Inc.

Discussed with: alc, jeffr, and kib

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Update to current version of head.

Resurrect pmap_is_referenced() and use it in mincore(). Essentially,
pmap_ts_referenced() is not always appropriate for checking whether or
not pages have been referenced because it clears any refer

Resurrect pmap_is_referenced() and use it in mincore(). Essentially,
pmap_ts_referenced() is not always appropriate for checking whether or
not pages have been referenced because it clears any reference bits
that it encounters. For example, in mincore(), clearing the reference
bits has two negative consequences. First, it throws off the activity
count calculations performed by the page daemon. Specifically, a page
on which mincore() has called pmap_ts_referenced() looks less active
to the page daemon than it should. Consequently, the page could be
deactivated prematurely by the page daemon. Arguably, this problem
could be fixed by having mincore() duplicate the activity count
calculation on the page. However, there is a second problem for which
that is not a solution. In order to clear a reference on a 4KB page,
it may be necessary to demote a 2/4MB page mapping. Thus, a mincore()
by one process can have the side effect of demoting a superpage
mapping within another process!

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