Commit Graph

943 Commits

Author SHA1 Message Date
Xin LI
1aaa945f67 MFV r258374:
4171 clean up spa_feature_*() interfaces

4172 implement extensible_dataset feature for use by other zpool
features

illumos/illumos-gate@2acef22db7

MFC after:	2 weeks
2013-12-24 07:14:25 +00:00
Xin LI
ec097c1634 MFV r258373:
4168 ztest assertion failure in dbuf_undirty

4169 verbatim import causes zdb to segfa
4170 zhack leaves pool in ACTIVE state

illumos/illumos-gate@7fdd916c47

MFC after:	2 weeks
2013-12-24 06:56:17 +00:00
Justin Hibbits
ad5017b513 Fix a brain-o. I had misread the limit as a size, but it's a pointer.
Submitted by:	Howard Su
MFC after:	2 weeks
X-MFC-with:	r259668
2013-12-21 00:37:32 +00:00
Justin Hibbits
a76f5d59f4 Fix a couple bugs in FBT PowerPC. Clamp the size to a 'instruction size' not
'byte size', and fix a typo.

MFC after:	2 weeks
2013-12-20 23:18:14 +00:00
Pawel Jakub Dawidek
4106732882 MFV r258923: 4188 assertion failed in dmu_tx_hold_free(): dn_datablkshift != 0
illumos/illumos-gate@bb411a08b0

MFC after:	3 days
2013-12-18 21:45:46 +00:00
Mark Johnston
7159310fa6 The fasttrap fork handler is responsible for removing tracepoints in the
child process that were inherited from its parent. However, this should
not be done in the case of a vfork, since the fork handler ends up removing
the tracepoints from the shared vm space, and userland DTrace probes in the
parent will no longer fire as a result.

Now the child of a vfork may trigger userland DTrace probes enabled in its
parent, so modify the fasttrap probe handler to handle this case and handle
the child process in the same way that it would handle the traced process.
In particular, if once traces function foo() in a process that vforks, and
the child calls foo(), fasttrap will treat this call as having come from the
parent. This is the behaviour of the upstream code.

While here, add #ifdef guards to some code that isn't present upstream.

MFC after:	1 month
2013-12-18 01:41:52 +00:00
Alan Somers
cd730bd6b2 sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c
When a da or ada device dissappears, outstanding IOs fail with
	ENXIO, not EIO.  The check for EIO was probably copied from Illumos,
	where that is indeed the correct errno.

	Without this change, pulling a busy drive from a zpool would usually
	turn it into UNAVAIL, even though pulling an idle drive would turn
	it into REMOVED.  With this change, it is REMOVED every time.

	Also, vdev_geom_io_intr shouldn't do zfs_post_remove, because that
	results in devd getting two resource.fs.zfs.removed events.  The
	comment said that the event had to be sent directly instead of
	through the async removal thread because "the DE engine is using
	this information to discard prevoius I/O errors".  However, the fact
	that vdev_geom_io_intr was never actually sending the events until
	now, and that vdev_geom_orphan never sent them at all, and that
	vdev_geom_orphan usually gets called about 2 seconds after the
	actual removal, means that FreeBSD's userland can cope with a late
	event just fine.

Approved by:	ken (mentor)
Sponsored by:	Spectra Logic Corporation
MFC after:	4 weeks
2013-12-12 00:27:22 +00:00
Mark Johnston
e53c69c1f5 Correct the check for errors from proc_rwmem().
MFC after:	2 weeks
2013-12-11 04:31:40 +00:00
Alexander Motin
f192c4873d Don't even try to read vdev labels from devices smaller then SPA_MINDEVSIZE
(64MB).  Even if we would find one somehow, ZFS kernel code rejects such
devices.  It is funny to look on attempts to read 4 256K vdev labels from
1.44MB floppy, though it is not very practical and quite slow.
2013-12-10 12:36:44 +00:00
Xin LI
9b11826d3d Expose spa_asize_inflation.
X-MFC-With:	r258632
2013-12-06 23:49:16 +00:00
Andriy Gapon
f77ffe1b22 zfs: add zfs_freebsd_putpages
this should be more optimal than writing pages one-by-one via zfs_write ->
update_pages in the case of multi-page putpages call

MFC after:	16 days
2013-11-29 15:39:39 +00:00
Andriy Gapon
6c5b7fffce zfs: add dmu_write_pages variant for freebsd
The freebsd variant of dmu_write_pages is hidden under _KERNEL
to avoid needlessly pulling in vm_page_t declaration.
Besides, this function seems to be useless for ZFS userland counterpart.

MFC after:	15 days
2013-11-29 15:34:43 +00:00
Andriy Gapon
fdbcc95a47 zfs: make zfs_map_page / zfs_unmap_page public
MFC after:	15 days
2013-11-29 15:33:40 +00:00
Andriy Gapon
998a42756c drop ZUT_OBJ, zfs unit testing driver never materialzied in freebsd
MFC after:	5 days
2013-11-29 15:32:53 +00:00
Andriy Gapon
ac79eedf85 zfs mappedread_sf: assert that a page is never partially valid
ZFS never partially validates or invalidates a page.
The higher level VM should not do that either.
mappedread_sf correct operation depends on a page being either fully
valid or invalid.

MFC after:	7 days
2013-11-29 12:19:52 +00:00
Andriy Gapon
be3d0087dc MFV r258665: 4347 ZPL can use dmu_tx_assign(TXG_WAIT)
illumos/illumos-gate@e722410c49

MFC after:	9 days
X-MFC after:	r258632
2013-11-28 19:44:36 +00:00
Andriy Gapon
456a87bb3b MFV r258371,r258372: 4101 metaslab_debug should allow for fine-grained control
4101 metaslab_debug should allow for fine-grained control
4102 space_maps should store more information about themselves
4103 space map object blocksize should be increased
4104 ::spa_space no longer works
4105 removing a mirrored log device results in a leaked object
4106 asynchronously load metaslab

illumos/illumos-gate@0713e232b7

Note that some tunables have been removed and some new tunables have
been added.  Of particular note, FreeBSD-only knob
vfs.zfs.space_map_last_hope is removed as it was a nop for some time now
(after one of the previous merges from upstream).

MFC after:	11 days
Sponsored by:	HybridCluster [merge]
2013-11-28 19:37:22 +00:00
Andriy Gapon
02727275c5 opensolaris compat: add taskq_wait emulation
MFC after:	10 days
2013-11-28 19:17:11 +00:00
Andriy Gapon
7bc07f0575 fix a serious bug in r258632: offset parameter must be set in zio
In illumos all ioctl zio-s are "global" at the moment.  That is they act
on a whole disk, e.g. a cache flush command, and thus do not need either
offset or size parameters.
FreeBSD, on the other hand, has support for TRIM command and that
command requires proper offset and size parameters.
Without this fix all TRIM commands act on the start of any disk or
partition used by ZFS destroying any data there.

Pointyhat to:	avg
Tested by:	sbruno
MFC after:	3 days
X-MFC with:	r258632
Sponsored by:	HybridCluster
2013-11-28 08:48:49 +00:00
Andriy Gapon
2ac1eeec44 fix debug.zfs_flags sysctl description in r258638
Pointyhat to:	avg
MFC after:	3 days
2013-11-26 10:57:09 +00:00
Andriy Gapon
78affb8591 expose zfs_flags as debug.zfs_flags r/w tunable and sysctl
This knob is purposefully hidden under debug.

MFC after:	5 days
Sponsored by:	HybridCluster
2013-11-26 10:46:43 +00:00
Andriy Gapon
3761ac95f7 MFV r258376: 3964 L2ARC should always compress metadata buffers
illumos/illumos-gate@e4be62a2b7

MFC after:	10 days
Sponsored by:	HybridCluster [merge]
2013-11-26 10:14:23 +00:00
Andriy Gapon
fd51e905e2 MFV r255256: 3954 metaslabs continue to load even after hitting zfs_mg_alloc_failure limit
4080 zpool clear fails to clear pool
4081 need zfs_mg_noalloc_threshold

illumos/illumos-gate@22e30981d8

MFC after:	10 days
Sponsored by:	HybridCluster [merge]
2013-11-26 10:02:02 +00:00
Andriy Gapon
2a4704ab01 MFV r255255: 4045 zfs write throttle & i/o scheduler performance work
illumos/illumos-gate@69962b5647

Please note the following changes:
- zio_ioctl has lost its priority parameter and now TRIM is executed
  with 'now' priority
- some knobs are gone and some new knobs are added; not all of them are
  exposed as tunables / sysctls yet

MFC after:	10 days
Sponsored by:	HybridCluster [merge]
2013-11-26 09:57:14 +00:00
Andriy Gapon
fb8171c240 MFV r247578: 3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock is piping hot
illumos/illumos-gate@ec94d32216

MFC after:	9 days
Sponsored by:	HybridCluster [merge]
2013-11-26 09:45:48 +00:00
Andriy Gapon
34140e78ab 734 taskq_dispatch_prealloc() desired
943 zio_interrupt ends up calling taskq_dispatch with TQ_SLEEP
illumos/illumos-gate@5aeb94743e

Essentially FreeBSD taskqueues already operate in a mode that
was added to Illumos with taskq_dispatch_ent change.
We even exposed the superior FreeBSD interface as taskq_dispatch_safe.
Now we just rename taskq_dispatch_safe to taskq_dispatch_ent and
struct struct ostask to taskq_ent_t, so that code differences will be
minimal.

After this change sys/cddl/compat/opensolaris/sys/taskq.h header is no
longer needed.

Note that this commit is not an MFV because the upstream change was not
individually committed to the vendor area.

MFC after:	8 days
2013-11-26 09:26:18 +00:00
Andriy Gapon
2dbdedbc46 opensolaris taskq: some cosmetic changes
- drop trailing whitespace
- remove redundant "extern" from function declarations
- remove unused macro

MFC after:	1 week
2013-11-26 09:10:01 +00:00
Andriy Gapon
a776a1c1c5 sdt: add support for solaris/illumos style DTRACE_PROBE macros
The new macros are implemented in terms of SDT_PROBE_DEFINE and SDT_PROBE.
Probes defined in this way will appear under SDT provider named "sdt".
Parameter types are exposed via SDT_PROBE_ARGTYPE.
This is something that illumos does not have by default.

This kind of SDT probes is already present in ZFS code, so those probes
will now be available if KDTRACE_HOOKS options is enabled.

A potential future illumos compatibility enhancement is to encode a provider
name as a prefix in a probe name.

Reviewed by:	markj
MFC after:	3 weeks
X-MFC after:	r258622
2013-11-26 08:49:53 +00:00
Andriy Gapon
d9fae5ab88 dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE
In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Reviewed by:	markj
MFC after:	3 weeks
2013-11-26 08:46:27 +00:00
Pawel Jakub Dawidek
1cef014007 When append-only, immutable or read-only flag is set don't allow for
hard links creation. This matches UFS behaviour.

Reported by:	Oleg Ginzburg <olevole@olevole.ru>
MFC after:	1 month
2013-11-25 21:17:14 +00:00
Attilio Rao
54366c0bd7 - For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
  calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
  version of the releasing functions for mutex, rwlock and sxlock.
  Failing to do so skips the lockstat_probe_func invokation for
  unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
  kernel compiled without lock debugging options, potentially every
  consumer must be compiled including opt_kdtrace.h.
  Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
  dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
  is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested.  As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while.  Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by:	EMC / Isilon storage division
Discussed with:	rstone
[0] Reported by:	rstone
[1] Discussed with:	philip
2013-11-25 07:38:45 +00:00
Andriy Gapon
a7236350c3 MFV r258378: 4089 NULL pointer dereference in arc_read()
illumos/illumos-gate@57815f6b95

Tested by:	adrian
MFC after:	4 days
2013-11-20 11:52:32 +00:00
Andriy Gapon
c5f4a0a2eb MFV r258377: 4088 use after free in arc_release()
illumos/illumos-gate@ccc22e1304

MFC after:	5 days
2013-11-20 11:47:50 +00:00
Justin Hibbits
de950c79f3 Fix the function search space.
Submitted by:	Howard Su
2013-11-20 01:33:13 +00:00
Andriy Gapon
3fd7f7bef7 zfs page_busy: fix the boundaries of the cleared range
This is a fix for a regression introduced in r246293.

vm_page_clear_dirty expects the range to have DEV_BSIZE aligned boundaries,
otherwise it extends them.  Thus it can happen that the whole page is
marked clean while actually having some small dirty region(s).
This commit makes the range properly aligned and ensures that only
the clean data is marked as such.

It would interesting to evaluate how much benefit clearing with DEV_BSIZE
granularity produces.  Perhaps instead we should clear the whole page
when it is completely overwritten and don't bother clearing any bits
if only a portion a page is written.

Reported by:	George Hartzell <hartzell@alerce.com>,
		Richard Todd <rmtodd@servalan.servalan.com>
Tested by:	George Hartzell <hartzell@alerce.com>,
Reviewed by:	kib
MFC after:	5 days
2013-11-19 18:43:47 +00:00
Alexander Motin
c5068af559 Reenable vfs.zfs.zio.use_uma for amd64, disabled at r209261.
On machines with seveal CPUs and enough RAM this can easily twice improve
ZFS performance or twice reduce CPU usage.  It was disabled three years
ago due to memory and KVA exhaustion reports, but our VM subsystem got
improved a lot since that time, hopefully enough to make another try.
2013-11-19 11:19:07 +00:00
Alan Somers
1f9e80bcdb opensolaris/uts/common/dtrace/fasttrap.c
Fix several problems that can cause panics on kldload and kldunload.

	* kproc_create(fasttrap_pid_cleanup_cb, ...) gets called before
	  fasttrap_provs.fth_table gets allocated.  This can lead to a panic
	  on module load, because fasttrap_pid_cleanup_cb references
	  fasttrap_provs.fth_table.  Move kproc_create down after the point
	  that fasttrap_provs.fth_table gets allocated, and modify the error
	  handling accordingly.

	* dtrace_fasttrap_{fork,exec,exit} weren't getting NULLed until
	  after fasttrap_provs.fth_table got freed.  That caused panics on
	  module unload because fasttrap_exec_exit calls
	  fasttrap_provider_retire, which references
	  fasttrap_provs.fth_table.  NULL those function pointers earlier.

	* There wasn't any code to destroy the
	  fasttrap_{tpoints,provs,procs}.fth_table mutexes on module unload,
	  leading to a resource leak when WITNESS is enabled.  Destroy those
	  mutexes during fasttrap_unload().

Reviewed by:	markj
Approved by:	ken (mentor)
Sponsored by:	Spectra Logic
MFC after:	4 weeks
2013-11-18 16:51:56 +00:00
Steven Hartland
8dfd07b976 Fix ZFS deadlock when sending a snapshot which is mounted.
MFC after:	1 week
Sponsored by:	Multiplay
2013-11-18 11:28:19 +00:00
Mark Johnston
dd580326fe The fasttrap ioctl used to create probes takes a variable-sized argument.
It was not being correctly copied into the kernel on FreeBSD, and as a
result, probes with multiple probe sites were not being created properly.
To fix this, change the ioctl definition so that the fasttrap ioctl handler
is responsible for copying in userland data.

Submitted by:	Prashanth Kumar <pra_udupi@yahoo.co.in>
MFC after:	1 month
2013-11-18 03:24:50 +00:00
Alexander Motin
e5056f9882 Introduce allocation cache to store LZ4 compression contexts without kicking
VM subsystem twice for every written record.

Tests on 24-core system show double reduction of CPU time spent on copying
single large well-compressed file.

This patch is not really needed on illumos (while not harm either) since
their memory allocator by default uses caching for all requests up to 128K.

Reviewed by:	Saso Kiselkov <skiselkov.ml@gmail.com>
2013-11-14 15:54:54 +00:00
Mark Johnston
a4cbcb127c Use suword32 and suword64 instead of copyout(9). This fixes a bug in the
emulation of the call instruction caused by reversing the uaddr and kaddr
arguments when copying data out to userland: the suword* functions take the
uaddr as the first argument whereas copyout(9) takes the kaddr as the first
argument. This also partially undoes the fixes from r257143.

Submitted by:	Prashanth Kumar <pra_udupi@yahoo.co.in> (original version)
MFC after:	1 month
2013-11-05 06:13:46 +00:00
Mark Johnston
57170f49f2 Remove references to an unused fasttrap probe hook, and remove the
corresponding x86 trap type. Userland DTrace probes are currently handled
by the other fasttrap hooks (dtrace_pid_probe_ptr and
dtrace_return_probe_ptr).

Discussed with:	rpaulo
2013-10-31 02:35:00 +00:00
Mark Johnston
9c06d5a051 Do some cleanup of the SDT code. In particular,
* Remove the unused sdt cdev.
* Don't bother keeping a list of probes in struct sdt_prov; it's not needed.
* Invoke sdt_load and sdt_unload from the module handler instead of
  registering separate SYSINITs.
* Keep to within 80 columns.
* Check for errors from dtrace_unregister().
2013-10-26 06:23:51 +00:00
Mark Johnston
165de3f338 Fix a couple of bugs in the fasttrap emulation of a "push %rbp" instruction:
the code was trying to save the stack pointer rather than the frame pointer,
and the arguments to copyout(9) were reversed, so nothing ended up being
saved on the stack. This would cause process crashes when the pid provider
was being used to instrument calls of a function starting with this
instruction.

Reported by:	symbolics@gmx.com
Tested by:	symbolics@gmx.com (earlier version)
MFC after:	2 weeks
2013-10-26 03:21:54 +00:00
Justin Hibbits
594ce9ad6f ELF PowerPC64 ABI puts the LR save word at 16 byte offset, not 8. 2013-10-25 00:17:12 +00:00
Steven Hartland
c28078e903 Improve ZFS N-way mirror read performance by using load and locality
information.

The existing algorithm selects a preferred leaf vdev based on offset of the zio
request modulo the number of members in the mirror. It assumes the devices are
of equal performance and that spreading the requests randomly over both drives
will be sufficient to saturate them. In practice this results in the leaf vdevs
being under utilized.

The new algorithm takes into the following additional factors:
* Load of the vdevs (number outstanding I/O requests)
* The locality of last queued I/O vs the new I/O request.

Within the locality calculation additional knowledge about the underlying vdev
is considered such as; is the device backing the vdev a rotating media device.

This results in performance increases across the board as well as significant
increases for predominantly streaming loads and for configurations which don't
have evenly performing devices.

The following are results from a setup with 3 Way Mirror with 2 x HD's and
1 x SSD from a basic test running multiple parrallel dd's.

With pre-fetch disabled (vfs.zfs.prefetch_disable=1):

== Stripe Balanced (default) ==
Read 15360MB using bs: 1048576, readers: 3, took 161 seconds @ 95 MB/s
== Load Balanced (zfslinux) ==
Read 15360MB using bs: 1048576, readers: 3, took 297 seconds @ 51 MB/s
== Load Balanced (locality freebsd) ==
Read 15360MB using bs: 1048576, readers: 3, took 54 seconds @ 284 MB/s

With pre-fetch enabled (vfs.zfs.prefetch_disable=0):

== Stripe Balanced (default) ==
Read 15360MB using bs: 1048576, readers: 3, took 91 seconds @ 168 MB/s
== Load Balanced (zfslinux) ==
Read 15360MB using bs: 1048576, readers: 3, took 108 seconds @ 142 MB/s
== Load Balanced (locality freebsd) ==
Read 15360MB using bs: 1048576, readers: 3, took 48 seconds @ 320 MB/s

In addition to the performance changes the code was also restructured, with
the help of Justin Gibbs, to provide a more logical flow which also ensures
vdevs loads are only calculated from the set of valid candidates.

The following additional sysctls where added to allow the administrator
to tune the behaviour of the load algorithm:
* vfs.zfs.vdev.mirror.rotating_inc
* vfs.zfs.vdev.mirror.rotating_seek_inc
* vfs.zfs.vdev.mirror.rotating_seek_offset
* vfs.zfs.vdev.mirror.non_rotating_inc
* vfs.zfs.vdev.mirror.non_rotating_seek_inc

These changes where based on work started by the zfsonlinux developers:
https://github.com/zfsonlinux/zfs/pull/1487

Reviewed by:	gibbs, mav, will
MFC after:	2 weeks
Sponsored by:	Multiplay
2013-10-23 09:54:58 +00:00
Steven Hartland
70c3432663 Use the vdev's ashift to calculate the supported min block size passed to
zio_compress_data(..) when compressing l2arc buffers.

This eliminates l2arc I/O errors, which resulted in very poor performance on
vdev's configured with block size greater than 512b due to compression
assuming a smaller min block size than the vdev supports.

MFC after:	2 days
2013-10-22 13:31:36 +00:00
Alexander Motin
40ea77a036 Merge GEOM direct dispatch changes from the projects/camlock branch.
When safety requirements are met, it allows to avoid passing I/O requests
to GEOM g_up/g_down thread, executing them directly in the caller context.
That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid
several context switches per I/O.

The defined now safety requirements are:
 - caller should not hold any locks and should be reenterable;
 - callee should not depend on GEOM dual-threaded concurency semantics;
 - on the way down, if request is unmapped while callee doesn't support it,
   the context should be sleepable;
 - kernel thread stack usage should be below 50%.

To keep compatibility with GEOM classes not meeting above requirements
new provider and consumer flags added:
 - G_CF_DIRECT_SEND -- consumer code meets caller requirements (request);
 - G_CF_DIRECT_RECEIVE -- consumer code meets callee requirements (done);
 - G_PF_DIRECT_SEND -- provider code meets caller requirements (done);
 - G_PF_DIRECT_RECEIVE -- provider code meets callee requirements (request).
Capable GEOM class can set them, allowing direct dispatch in cases where
it is safe.  If any of requirements are not met, request is queued to
g_up or g_down thread same as before.

Such GEOM classes were reviewed and updated to support direct dispatch:
CONCAT, DEV, DISK, GATE, MD, MIRROR, MULTIPATH, NOP, PART, RAID, STRIPE,
VFS, ZERO, ZFS::VDEV, ZFS::ZVOL, all classes based on g_slice KPI (LABEL,
MAP, FLASHMAP, etc).

To declare direct completion capability disk(9) KPI got new flag equivalent
to G_PF_DIRECT_SEND -- DISKFLAG_DIRECT_COMPLETION.  da(4) and ada(4) disk
drivers got it set now thanks to earlier CAM locking work.

This change more then twice increases peak block storage performance on
systems with manu CPUs, together with earlier CAM locking changes reaching
more then 1 million IOPS (512 byte raw reads from 16 SATA SSDs on 4 HBAs to
256 user-level threads).

Sponsored by:	iXsystems, Inc.
MFC after:	2 months
2013-10-22 08:22:19 +00:00
Mark Johnston
7e75d58610 When fetching function arguments out of a frame on amd64, explicitly select
the register based on the argument index rather than relying on the fields
in struct reg to be in the right order. This assumption is incorrect on
FreeBSD and generally led to bogus argument values for the sixth argument
of PID and USDT probes; the first five are passed directly to dtrace_probe()
via the fasttrap trap handler and so were correctly handled.

MFC after:	2 weeks
2013-10-21 04:15:55 +00:00
Mark Johnston
e572bc11ec Add a function, memstr, which can be used to convert a buffer of
null-separated strings to a single string. This can be used to print the
full arguments of a process using execsnoop (from the DTrace toolkit) or
with the following one-liner:

dtrace -n 'syscall::execve:return {trace(curpsinfo->pr_psargs);}'

Note that this relies on the process arguments being cached via the struct
proc, which means that it will not work for argvs longer than
kern.ps_arg_cache_limit. However, the following rather non-portable
script can be used to extract any argv at exec time:

fbt::kern_execve:entry
{
    printf("%s", memstr(args[1]->begin_argv, ' ',
        args[1]->begin_envv - args[1]->begin_argv));
}

The debug.dtrace.memstr_max sysctl limits the maximum argument size to
memstr(). Thanks to Brendan Gregg for helpful comments on freebsd-dtrace.

Tested by:	Fabian Keil (earlier version)
MFC after:	2 weeks
2013-10-16 01:39:26 +00:00