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
Code should just use the devtoname() function to obtain the name of a
character device. Also add const keywords to pieces of code that need it
to build properly.
MFC after: 2 weeks
disconnected swap device.
This is quick and imperfect solution, as swap device will still be opened
and GEOM will not be able to destroy it. Proper solution would be to
automatically turn off and close disconnected swap device, but with existing
code it will cause panic if there is at least one page on device, even if
it is unimportant page of the user-level process. It needs some work.
Reviewed by: kib@
MFC after: 1 week
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
flags field. Updates to the atomic flags are performed using the atomic
ops on the containing word, do not require any vm lock to be held, and
are non-blocking. The vm_page_aflag_set(9) and vm_page_aflag_clear(9)
functions are provided to modify afalgs.
Document the changes to flags field to only require the page lock.
Introduce vm_page_reference(9) function to provide a stable KPI and
KBI for filesystems like tmpfs and zfs which need to mark a page as
referenced.
Reviewed by: alc, attilio
Tested by: marius, flo (sparc64); andreast (powerpc, powerpc64)
Approved by: re (bz)
after the conversion of the swap device size to the page size units,
not before. That lifts the limit on the usable swap partition size
from 32GB to 256GB, that is less depressing for the modern systems.
Submitted by: Alexander V. Chernikov <melifaro ipfw ru>
Reviewed by: alc
Approved by: re (bz)
MFC after: 2 weeks
configured swap devices in the Linux-compatible format.
Based on the submission by: Robert Millan <rmh debian org>
PR: kern/159281
Reviewed by: bde
Approved by: re (kensmith)
MFC after: 2 weeks
won't happen before 9.0. This commit adds "#ifdef RACCT" around all the
"PROC_LOCK(p); racct_whatever(p, ...); PROC_UNLOCK(p)" instances, in order
to avoid useless locking/unlocking in kernels built without "options RACCT".
in "struct vm_object". This is required to make it possible to account
for per-jail swap usage.
Reviewed by: kib@
Tested by: pho@
Sponsored by: FreeBSD Foundation
swp_pager_force_pagein(). By dirtying the page, swp_pager_force_pagein()
forces vm_page_dontneed() to insert the page at the head of the inactive
queue, just like vm_page_deactivate() does. Moreover, because the page
was invalid, it can't have been mapped, and thus the other effect of
vm_page_dontneed(), clearing the page's reference bits has no effect. In
summary, there is no reason to call vm_page_dontneed() since its effect
will be identical to calling the simpler vm_page_deactivate().
vm_page_try_to_free(). Consequently, push down the page queues lock into
pmap_enter_quick(), pmap_page_wired_mapped(), pmap_remove_all(), and
pmap_remove_write().
Push down the page queues lock into Xen's pmap_page_is_mapped(). (I
overlooked the Xen pmap in r207702.)
Switch to a per-processor counter for the total number of pages cached.
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
wired. Kstack pages are wired, this change prepares swap pager for handling
of long runs of kstack pages.
Noted and reviewed by: alc
Tested by: pho
MFC after: 2 weeks
either redundant or harmful, depending on the caller. For example, when
called by vm_fault(), it is redundant. However, when called by
vm_thread_swapin(), it is harmful. Specifically, if the thread is later
swapped out, having PG_REFERENCED set on its stack pages leads the page
daemon to reactivate these stack pages and delay their reclamation.
Reviewed by: kib
MFC after: 3 weeks
from tuning(7). One of the descriptions references tuning(7) because
it is too complex to adequatly describe here (it is not a simple
boolean sysctl) and users should be warned to that.
Reviewed by: alc, kib
Approved by: gnn (mentor)
Call priv_check(PRIV_VM_SWAP_NORLIMIT) only when per-uid limit is
actually exceed.
Both changes aim at calling priv_check(9) only for the cases when
privilege is actually exercised by the process.
Reported and tested by: rwatson
Reviewed by: alc
MFC after: 3 days
rlimit RLIMIT_SWAP that limits the amount of swap that may be reserved
for the uid.
The accounting information (charge) is associated with either map entry,
or vm object backing the entry, assuming the object is the first one
in the shadow chain and entry does not require COW. Charge is moved
from entry to object on allocation of the object, e.g. during the mmap,
assuming the object is allocated, or on the first page fault on the
entry. It moves back to the entry on forks due to COW setup.
The per-entry granularity of accounting makes the charge process fair
for processes that change uid during lifetime, and decrements charge
for proper uid when region is unmapped.
The interface of vm_pager_allocate(9) is extended by adding struct ucred *,
that is used to charge appropriate uid when allocation if performed by
kernel, e.g. md(4).
Several syscalls, among them is fork(2), may now return ENOMEM when
global or per-uid limits are enforced.
In collaboration with: pho
Reviewed by: alc
Approved by: re (kensmith)
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.
Discussed with: pjd
pmap_clear_modify() on a page is pointless if that page is not mapped or
it is only mapped for read access. Instead, assert that the page is not
mapped or not mapped for write access as appropriate.
Eliminate unnecessary clearing of a page's dirty mask. Instead, assert
that the page's dirty mask is clear.
into the separate function vm_pageout_oom(). Supply a parameter for
vm_pageout_oom() describing a reason for the call.
Call vm_pageout_oom() from the swp_pager_meta_build() when swap zone
is exhausted.
Reviewed by: alc
Tested by: pho, jhb
MFC after: 2 weeks
for the bio for swapout write. It allows the page allocator to drain
free page list deeper. As result, a deadlock where pageout deamon sleeps
waiting for bio to be allocated for swapout is no more reproducable in
practice.
Alan said that M_USE_RESERVE shall be ressurrected and used there, but
until this is implemented, M_NOWAIT does exactly what is needed.
Tested by: pho, kris
Reviewed by: alc
No objections from: phk
MFC after: 2 weeks (RELENG_7 only)
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.
Manpage and FreeBSD_version will be updated through further commits.
As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.
Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>
assertion hit in swapoff_one() when we un-mount a swap partition. We
should be using curthread where we used thread0 before. This change
also replaces the thread argument with a credential argument, as the
MAC framework only requires the cred.
It should be noted that this allows the machine to be rebooted without
panicing with "cannot differ from curthread or NULL" when MAC is enabled.
Submitted by: rwatson
Reviewed by: attilio
MFC after: 2 weeks
from Mac OS X Leopard--rationalize naming for entry points to
the following general forms:
mac_<object>_<method/action>
mac_<object>_check_<method/action>
The previous naming scheme was inconsistent and mostly
reversed from the new scheme. Also, make object types more
consistent and remove spaces from object types that contain
multiple parts ("posix_sem" -> "posixsem") to make mechanical
parsing easier. Introduce a new "netinet" object type for
certain IPv4/IPv6-related methods. Also simplify, slightly,
some entry point names.
All MAC policy modules will need to be recompiled, and modules
not updates as part of this commit will need to be modified to
conform to the new KPI.
Sponsored by: SPARTA (original patches against Mac OS X)
Obtained from: TrustedBSD Project, Apple Computer
vm_object_terminate() on a device-backed object at the same time that
another processor, call it Pa, is performing dev_pager_alloc() on the
same device. The problem is that vm_pager_object_lookup() should not be
allowed to return a doomed object, i.e., an object with OBJ_DEAD set,
but it does. In detail, the unfortunate sequence of events is: Pt in
vm_object_terminate() holds the doomed object's lock and sets OBJ_DEAD
on the object. Pa in dev_pager_alloc() holds dev_pager_sx and calls
vm_pager_object_lookup(), which returns the doomed object. Next, Pa
calls vm_object_reference(), which requires the doomed object's lock, so
Pa waits for Pt to release the doomed object's lock. Pt proceeds to the
point in vm_object_terminate() where it releases the doomed object's
lock. Pa is now able to complete vm_object_reference() because it can
now complete the acquisition of the doomed object's lock. So, now the
doomed object has a reference count of one! Pa releases dev_pager_sx
and returns the doomed object from dev_pager_alloc(). Pt now acquires
dev_pager_mtx, removes the doomed object from dev_pager_object_list,
releases dev_pager_mtx, and finally calls uma_zfree with the doomed
object. However, the doomed object is still in use by Pa.
Repeating my key point, vm_pager_object_lookup() must not return a
doomed object. Moreover, the test for the object's state, i.e.,
doomed or not, and the increment of the object's reference count
should be carried out atomically.
Reviewed by: kib
Approved by: re (kensmith)
MFC after: 3 weeks
Now, we assume no more sched_lock protection for some of them and use the
distribuited loads method for vmmeter (distribuited through CPUs).
Reviewed by: alc, bde
Approved by: jeff (mentor)
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)
