Commit Graph

3270 Commits

Author SHA1 Message Date
Konstantin Belousov
a36f55322c Make MAP_NOSYNC handling in the vm_fault() read-locked object path
compatible with write-locked path.  Test for MAP_ENTRY_NOSYNC and set
VPO_NOSYNC for pages with dirty mask zero (this does not exclude a
possibility that the page is dirty, e.g. due to read fault on
writeable mapping and consequent write; the same issue exists in the
slow path).

Use helper vm_fault_dirty() to unify fast and slow path handling of
VPO_NOSYNC and setting the dirty mask.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
2014-10-10 19:27:36 +00:00
Bryan Venteicher
111fbcd5ed Change the UMA mutex into a rwlock
Acquire the lock in read mode when just needed to ensure the stability
of the keg list. The UMA lock may be held for a long time (relatively
speaking) in uma_reclaim() on machines with lots of zones/kegs. If the
uma_timeout() would fire during that period, subsequent callouts on that
CPU may be significantly delayed.

Reviewed by:	jhb
2014-10-05 21:34:56 +00:00
Bryan Venteicher
6e5254e0d7 Remove stray uma_mtx lock/unlock in zone_drain_wait()
Callers of zone_drain_wait(M_WAITOK) do not need to hold (and were not)
the uma_mtx, but we would attempt to unlock and relock the mutex if we
had to sleep because the zone was already draining. The M_NOWAIT callers
may hold the uma_mtx, but we do not sleep in that case.

Reviewed by:	jhb
MFC after:	3 days
2014-10-05 03:18:30 +00:00
Konstantin Belousov
b76278407d Add kernel option KSTACK_USAGE_PROF to sample the stack depth on
interrupts and report the largest value seen as sysctl
debug.max_kstack_used.  Useful to estimate how close the kernel stack
size is to overflow.

In collaboration with:	Larry Baird <lab@gta.com>
Sponsored by:	The FreeBSD Foundation (kib)
MFC after:	1 week
2014-10-04 18:38:14 +00:00
Steven Hartland
14a0d74ea8 Refactor ZFS ARC reclaim checks and limits
Remove previously added kmem methods in favour of defines which
allow diff minimisation between upstream code base.

Rebalance ARC free target to be vm_pageout_wakeup_thresh by default
which eliminates issue where ARC gets minimised instead of balancing
with VM pageout. The restores the target point prior to r270759.

Bring in missing upstream only changes which move unused code to
further eliminate code differences.

Add additional DTRACE probe to aid monitoring of ARC behaviour.

Enable upstream i386 code paths on platforms which don't define
UMA_MD_SMALL_ALLOC.

Fix mixture of byte an page values in arc_memory_throttle i386 code
path value assignment of available_memory.

PR:		187594
Review:		D702
Reviewed by:	avg
MFC after:	1 week
X-MFC-With:	r270759 & r270861
Sponsored by:	Multiplay
2014-10-03 20:34:55 +00:00
Steven Hartland
f721133eb9 Fix ticks wrap issue of lowmem test in vm_pageout_scan
Reviewed by:	jhb (D818)
MFC after:	3 days
Sponsored by:	Multiplay
2014-09-24 14:35:08 +00:00
Konstantin Belousov
54432196db vm_map_pmap_enter() and pmap_enter_object() are currently not aware of
the wired attribute of the mapping.  As result, some pmap
implementations clear the wired state of the page table entries, which
breaks invariants and allows the entries to be lost.  Avoid calling
vm_map_pmap_enter() for the MADV_WILLNEED on the wired entry, the
pages must be already mapped.

Noted and reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
2014-09-23 18:54:23 +00:00
Konstantin Belousov
10204535af The vm_mmap_cdev() explicitely converts absence of both MAP_SHARED and
MAP_PRIVATE flags to MAP_SHARED.  Apparently, some code in tree, in
particular, libgeom, relied on this behaviour, see r271721.  For
regular file types, the absence of the flags is interpreted as
MAP_PRIVATE, and libc nlist used this (fixed in r271723).

Allow the implicit flags for legacy binaries.  Bump __FreeBSD_version
to get the ABI note on new binaries to check for in mmap code.

Remove the test for presence of one of the MAP_ANON, MAP_SHARED or
MAP_PRIVATE flags before fget_mmap().  For MAP_ANON, we already verify
that passed fd == -1.  For fd != -1, test after fget_mmap() (for newer
binaries) covers the case.

Reported by:	bdrewery, pho
Reviewed by:	jhb
Sponsored by:	The FreeBSD Foundation
2014-09-17 21:04:50 +00:00
John Baldwin
8bafac5444 Permit MAP_RENAME and MAP_NORESERVE for now. These flags should be removed, but at least
Chromium and OpenJDK use MAP_NORESERVE.
2014-09-16 17:21:06 +00:00
John Baldwin
5fd3f8b3b6 Add stricter checking of some mmap() arguments:
- Fail with EINVAL if an invalid protection mask is passed to mmap().
- Fail with EINVAL if an unknown flag is passed to mmap().
- Fail with EINVAL if both MAP_PRIVATE and MAP_SHARED are passed to mmap().
- Require one of either MAP_PRIVATE or MAP_SHARED for non-anonymous
  mappings.

Reviewed by:	alc, kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D698
2014-09-15 17:20:13 +00:00
Alan Cox
a7fecb4d3a Three improvements to vnode_pager_generic_getpages():
Eliminate an exclusive object lock acquisition and release on the expected
execution path.

Do page zeroing before the object lock is acquired rather than during the
time that the object lock is held.

Use vm_pager_free_nonreq() to eliminate duplicated code.

Reviewed by:	kib
MFC after:	6 weeks
Sponsored by:	EMC / Isilon Storage Division
2014-09-15 17:14:09 +00:00
Gleb Smirnoff
be58a555d2 Remove redundant declaration. vnode.h should be included before vnode_pager.h. 2014-09-15 15:49:29 +00:00
Konstantin Belousov
d15b55c554 Provide the unique implementation for the VOP_GETPAGES() method used
by ffs and ext2fs.  Remove duplicated call to vm_page_zero_invalid(),
done by VOP and by vm_pager_getpages().  Use vm_pager_free_nonreq().

Reviewed by:	alc (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	6 weeks (after r271596)
2014-09-15 12:28:29 +00:00
Alan Cox
396b3e34b4 Avoid an exclusive acquisition of the object lock on the expected execution
path through the NFS clients' getpages functions.

Introduce vm_pager_free_nonreq().  This function can be used to eliminate
code that is duplicated in many getpages functions.  Also, in contrast to
the code that currently appears in those getpages functions,
vm_pager_free_nonreq() avoids acquiring an exclusive object lock in one
case.

Reviewed by:	kib
MFC after:	6 weeks
Sponsored by:	EMC / Isilon Storage Division
2014-09-14 18:07:55 +00:00
Konstantin Belousov
33cad9e936 Fix mis-spelling of bits and types names in the vnode_pager_putpages().
The changes should not modify the generated code.

The pager->pgo_putpages() method takes int flags as its fourth
argument, while vnode_pager_putpages() used boolean_t (which is
typedef'ed to int).  The flags are from VM_PAGER_* namespace, while
vnode_pager_putpages() passed TRUE and OBJPC_SYNC to VOP_PUTPAGES(),
which both are numerically equal to VM_PAGER_PUT_SYNC.

Noted and reviewed by:	alc (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-09-14 10:27:36 +00:00
Alan Cox
81a065058c Update a stale comment. 2014-09-11 03:16:57 +00:00
Gleb Smirnoff
27ad26d8c7 Remove unused arguments for VOP_GETPAGES(), VOP_PUTPAGES(). 2014-09-10 12:36:41 +00:00
Alan Cox
64f096eeb2 Fix a boundary case error in vm_reserv_alloc_contig(): If a reservation
isn't being allocated for the last of the requested pages, because a
reservation won't fit in the gap between allocated pages, then the
reservation structure shouldn't be initialized.

While I'm here, improve the nearby comments.

Reported by:	jeff, pho
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
2014-09-10 05:52:30 +00:00
Alan Cox
0afcd3af8b Oops. vm_map_simplify_entry() is used by mac_proc_vm_revoke_recurse(), so
it can't be static.
2014-09-08 02:25:01 +00:00
Alan Cox
077ec27cd6 Make two functions static and eliminate an unused #define. 2014-09-08 00:19:03 +00:00
John Baldwin
1a83a822d2 Fix a typo. 2014-08-29 21:20:36 +00:00
Steven Hartland
4d19f4ad1f Refactor ZFS ARC reclaim logic to be more VM cooperative
Prior to this change we triggered ARC reclaim when kmem usage passed 3/4
of the total available, as indicated by vmem_size(kmem_arena, VMEM_ALLOC).

This could lead large amounts of unused RAM e.g. on a 192GB machine with
ARC the only major RAM consumer, 40GB of RAM would remain unused.

The old method has also been seen to result in extreme RAM usage under
certain loads, causing poor performance and stalls.

We now trigger ARC reclaim when the number of free pages drops below the
value defined by the new sysctl vfs.zfs.arc_free_target, which defaults
to the value of vm.v_free_target.

Credit to Karl Denninger for the original patch on which this update was
based.

PR:		191510 and 187594
Tested by:	dteske
MFC after:	1 week
Relnotes:	yes
Sponsored by:	Multiplay
2014-08-28 19:50:08 +00:00
Alan Cox
9452b5eda9 Back in the days when the kernel was single threaded, testing
"vm_paging_target() > 0" was a reasonable way of determining if the
inactive queue scan met its target.  However, now that other threads
can be allocating pages while the inactive queue scan is running, it's
an unreliable method.  The effect of it being unreliable is that we
can start swapping out processes when we didn't intend to.

This issue has existed since the kernel was multithreaded, but the
changes to the inactive queue target in 10.0-RELEASE have made its
effects visible.

This change introduces a more direct method for determining if the
inactive queue scan met its target that is not affected by the actions
of other threads.

Reported by:	Steve Polyack
Tested by:	pho, Steve Polyack (an earlier version)
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
2014-08-26 16:40:20 +00:00
Alan Cox
b9ce8cc2d7 Relax one of the conditions for mapping a page on the fast path.
Reviewed by:	kib
X-MFC with:	r270011
Sponsored by:	EMC / Isilon Storage Division
2014-08-23 05:24:31 +00:00
Konstantin Belousov
afe55ca373 Implement 'fast path' for the vm page fault handler. Or, it could be
called a scalable path.  When several preconditions hold, the vm
object lock for the object containing the faulted page is taken in
read mode, instead of write, which allows parallel faults processing
in the region.

Namely, the fast path is taken when the faulted page already exists
and does not need copy on write, is already fully valid, and not busy.
For technical reasons, fast path is avoided when the fault is the
first write on the vnode object, or when the fault is for wiring or
debugger read or write.

On the fast path, pmap_enter(9) is passed the PMAP_ENTER_NOSLEEP flag,
since object lock is kept.  Pmap might fail to create the entry, in
which case the fallback to slow path is performed.

Reviewed by:	alc
Tested by:	pho (previous version)
Hardware provided and hosted by:	The FreeBSD Foundation and
	 Sentex Data Communications
Sponsored by:	The FreeBSD Foundation
MFC after:	2 week
2014-08-15 07:30:14 +00:00
Alan Cox
9f746b66df Avoid pointless (but harmless) actions on unmanaged pages.
Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2014-08-14 15:46:15 +00:00
Konstantin Belousov
70978c93b8 If vm_page_grab() allocates a new page, the page is not inserted into
page queue even when the allocation is not wired.  It is
responsibility of the vm_page_grab() caller to ensure that the page
does not end on the vm_object queue but not on the pagedaemon queue,
which would effectively create unpageable unwired page.

In exec_map_first_page() and vm_imgact_hold_page(), activate the page
immediately after unbusying it, to avoid leak.

In the uiomove_object_page(), deactivate page before the object is
unlocked.  There is no leak, since the page is deactivated after
uiomove_fromphys() finished.  But allowing non-queued non-wired page
in the unlocked object queue makes it impossible to assert that leak
does not happen in other places.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-08-13 05:44:08 +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
Konstantin Belousov
39ffa8c138 Change pmap_enter(9) interface to take flags parameter and superpage
mapping size (currently unused).  The flags includes the fault access
bits, wired flag as PMAP_ENTER_WIRED, and a new flag
PMAP_ENTER_NOSLEEP to indicate that pmap should not sleep.

For powerpc aim both 32 and 64 bit, fix implementation to ensure that
the requested mapping is created when PMAP_ENTER_NOSLEEP is not
specified, in particular, wait for the available memory required to
proceed.

In collaboration with:	alc
Tested by:	nwhitehorn (ppc aim32 and booke)
Sponsored by:	The FreeBSD Foundation and EMC / Isilon Storage Division
MFC after:	2 weeks
2014-08-08 17:12:03 +00:00
Konstantin Belousov
385b4265fc The vm_pager_page_unswapped() pager op is only implemented for the
swap pager.  Swap pager uses a private mutex to protect swap metadata,
and does not rely on the vm object lock to ensure integrity of it.

Weaken the requirement for the vm object lock by only asserting locked
object in vm_pager_page_unswapped(), instead of locked exclusively.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-08-06 19:34:03 +00:00
Konstantin Belousov
faaf544760 Add wrappers to assert that vm object is unlocked and for try upgrade.
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-08-06 19:30:35 +00:00
Roger Pau Monné
5ebe728d53 vm_phys: improve robustness of fictitious ranges
With the current implementation of managed fictitious ranges when
also using VM_PHYSSEG_DENSE, a user could try to register a
fictitious range that starts inside of vm_page_array, but then
overrruns it (because the end of the fictitious range is greater than
vm_page_array_size + first_page). This would result in PHYS_TO_VM_PAGE
returning unallocated pages from past the end of vm_page_array. The
same could happen if a user tried to register a segment that starts
outside of vm_page_array but ends inside of it.

In order to fix this, allow vm_phys_fictitious_{reg/unreg}_range to
use a set of pages from vm_page_array, and allocate the rest.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, alc

vm/vm_phys.c:
 - Allow registering/unregistering fictitious ranges that overrun
   vm_page_array.
2014-08-05 10:29:01 +00:00
Alan Cox
a695d9b25b Retire pmap_change_wiring(). We have never used it to wire virtual pages.
We continue to use pmap_enter() for that.  For unwiring virtual pages, we
now use pmap_unwire(), which unwires a range of virtual addresses instead
of a single virtual page.

Sponsored by:	EMC / Isilon Storage Division
2014-08-03 20:40:51 +00:00
Alan Cox
0b69568411 Rewrite a loop in vm_map_wire() so that gcc doesn't think that the variable
"rv" is uninitialized.

Reported by:	bz
2014-08-02 17:58:20 +00:00
Alan Cox
66cd575b28 Handle wiring failures in vm_map_wire() with the new functions
pmap_unwire() and vm_object_unwire().

Retire vm_fault_{un,}wire(), since they are no longer used.

(See r268327 and r269134 for the motivation behind this change.)

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2014-08-02 16:10:24 +00:00
Alan Cox
0346250941 When unwiring a region of an address space, do not assume that the
underlying physical pages are mapped by the pmap.  If, for example, the
application has performed an mprotect(..., PROT_NONE) on any part of the
wired region, then those pages will no longer be mapped by the pmap.
So, using the pmap to lookup the wired pages in order to unwire them
doesn't always work, and when it doesn't work wired pages are leaked.

To avoid the leak, introduce and use a new function vm_object_unwire()
that locates the wired pages by traversing the object and its backing
objects.

At the same time, switch from using pmap_change_wiring() to the recently
introduced function pmap_unwire() for unwiring the region's mappings.
pmap_unwire() is faster, because it operates a range of virtual addresses
rather than a single virtual page at a time.  Moreover, by operating on
a range, it is superpage friendly.  It doesn't waste time performing
unnecessary demotions.

Reported by:	markj
Reviewed by:	kib
Tested by:	pho, jmg (arm)
Sponsored by:	EMC / Isilon Storage Division
2014-07-26 18:10:18 +00:00
Konstantin Belousov
4bace8e721 Correct assertion. The shadowing object cannot be tmpfs vm object,
and tmpfs object cannot shadow.  In other words, tmpfs vm object is
always at the bottom of the shadow chain.

Reported and tested by:	bdrewery
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-07-24 10:25:42 +00:00
Konstantin Belousov
f08f7dca40 The OBJ_TMPFS flag of vm_object means that there is unreclaimed tmpfs
vnode for the tmpfs node owning this object.  The flag is currently
used for two purposes.  First, it allows to correctly handle VV_TEXT
for tmpfs vnode when the ref count on the object is decremented to 1,
similar to vnode_pager_dealloc() for regular filesystems.  Second, it
prevents some operations, which are done on OBJT_SWAP vm objects
backing user anonymous memory, but are incorrect for the object owned
by tmpfs node.

The second kind of use of the OBJ_TMPFS flag is incorrect, since the
vnode might be reclaimed, which clears the flag, but vm object
operations must still be disallowed.

Introduce one more flag, OBJ_TMPFS_NODE, which is permanently set on
the object for VREG tmpfs node, and used instead of OBJ_TMPFS to test
whether vm object collapse and similar actions should be disabled.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-07-14 09:30:37 +00:00
Roger Pau Monné
38d6b2dcb2 vm_phys: remove limitation on number of fictitious regions
The number of vm fictitious regions was limited to 8 by default, but
Xen will make heavy usage of those kind of regions in order to map
memory from foreign domains, so instead of increasing the default
number, change the implementation to use a red-black tree to track vm
fictitious ranges.

The public interface remains the same.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, alc
Approved by: gibbs

vm/vm_phys.c:
 - Replace the vm fictitious static array with a red-black tree.
 - Use a rwlock instead of a mutex, since now we also need to take the
   lock in vm_phys_fictitious_to_vm_page, and it can be shared.
2014-07-09 08:12:58 +00:00
Marcel Moolenaar
e7d939bda2 Remove ia64.
This includes:
o   All directories named *ia64*
o   All files named *ia64*
o   All ia64-specific code guarded by __ia64__
o   All ia64-specific makefile logic
o   Mention of ia64 in comments and documentation

This excludes:
o   Everything under contrib/
o   Everything under crypto/
o   sys/xen/interface
o   sys/sys/elf_common.h

Discussed at: BSDcan
2014-07-07 00:27:09 +00:00
Alan Cox
09132ba6ac Introduce pmap_unwire(). It will replace pmap_change_wiring(). There are
several reasons for this change:

pmap_change_wiring() has never (in my memory) been used to set the wired
attribute on a virtual page.  We have always used pmap_enter() to do that.
Moreover, it is not really safe to use pmap_change_wiring() to set the wired
attribute on a virtual page.  The description of pmap_change_wiring() says
that it assumes the existence of a mapping in the pmap.  However, non-wired
mappings may be reclaimed by the pmap at any time.  (See pmap_collect().)
Many implementations of pmap_change_wiring() will crash if the mapping does
not exist.

pmap_unwire() accepts a range of virtual addresses, whereas
pmap_change_wiring() acts upon a single virtual page.  Since we are
typically unwiring a range of virtual addresses, pmap_unwire() will be more
efficient.  Moreover, pmap_unwire() allows us to unwire superpage mappings.
Previously, we were forced to demote the superpage mapping, because
pmap_change_wiring() only allowed us to express the unwiring of a single
base page mapping at a time.  This added to the overhead of unwiring for
large ranges of addresses, including the implicit unwiring that occurs at
process termination.

Implementations for arm and powerpc will follow.

Discussed with:	jeff, marcel
Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2014-07-06 17:42:38 +00:00
Hans Petter Selasky
af3b2549c4 Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
Glen Barber
37a107a407 Revert r267961, r267973:
These changes prevent sysctl(8) from returning proper output,
such as:

 1) no output from sysctl(8)
 2) erroneously returning ENOMEM with tools like truss(1)
    or uname(1)
 truss: can not get etype: Cannot allocate memory
2014-06-27 22:05:21 +00:00
Hans Petter Selasky
3da1cf1e88 Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies
2014-06-27 16:33:43 +00:00
Alan Cox
60169c88d9 Delay the call to crhold() in vm_map_insert() until we know that we won't
have to undo it by calling crfree().  This reduces the total number of calls
by vm_map_insert() to crhold() and crfree() by 45% in my tests.

Eliminate an unnecessary variable from vm_map_insert().

Reviewed by:	kib
Tested by:	pho
2014-06-26 16:04:03 +00:00
Alan Cox
eaaf9f7fce Now that vm_map_insert() sets MAP_ENTRY_GROWS_{DOWN,UP} on the stack entries
that it creates (r267645), we can place the check that blocks map entry
coalescing on stack entries in vm_map_simplify_entry() where it properly
belongs.

Reviewed by:	kib
2014-06-25 03:30:03 +00:00
Konstantin Belousov
b5f8c226ab Use correct names for the flags. MAP_ENTRY_GROWS_* have the same
numerical values as MAP_STACK_GROWS_*, but the former is for entries'
eflags, while the later for the cow argument of vm_map_insert().

Submitted by:	alc
2014-06-23 07:03:47 +00:00
Konstantin Belousov
5831f5fc52 Assert that the new entry is inserted into the right location in the
map entries list, and that it does not overlap with the previous and
next entries.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-06-20 07:01:53 +00:00
Alan Cox
39c18ce157 Eliminate a pointless call to vm_map_clip_start() from vm_map_growstack().
For this call to do anything at all we would have to have two overlapping
map entries.

Submitted by:	kib
2014-06-19 21:05:07 +00:00
Alan Cox
712efe66e2 When MAP_STACK_GROWS_{DOWN,UP} are passed to vm_map_insert() set the
corresponding flag(s) in the new map entry.  Previously, the caller was
responsible for setting them after vm_map_insert() returned.

Pass MAP_STACK_GROWS_DOWN to vm_map_insert() from vm_map_growstack() when
extending the stack in the downward direction.

Together these changes slightly simplify the caller's task when creating a
downward growing stack.  In particular, the caller no longer needs to clip
the previous entry, because the new stack entry can't possibly coalesce
with the previous entry.

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
2014-06-19 16:26:16 +00:00