Commit Graph

861 Commits

Author SHA1 Message Date
Xin LI
4acaabea05 MFV r251619:
ZFS needs better comments.

Illumos ZFS issues:
  3741 zfs needs better comments

MFC after:      2 weeks
2013-06-11 19:02:36 +00:00
Xin LI
9e43a32a5c MFV r251519:
* Illumos ZFS issue #3805 arc shouldn't cache freed blocks

Quote from the Illumos issue:

    ZFS should proactively evict freed blocks from the cache.

    Even though these freed blocks will never be used again, and thus
    will eventually be evicted, this causes us to use memory
    inefficiently for 2 reasons:

    1. A block that is freed has no chance of being accessed again, but
       will be kept in memory preferentially to a block that was accessed
       before it (and is thus older) but has not been freed and thus has
       at least some chance of being accessed again.

    2. We partition the ARC into several buckets:
       user data that has been accessed only once (MRU)
       metadata that has been accessed only once (MRU)
       user data that has been accessed more than once (MFU)
       metadata that has been accessed more than once (MFU)

    The user data vs metadata split is somewhat arbitrary, and the
    primary control on how much memory is used to cache data vs metadata
    is to simply try to keep the proportion the same as it has been in the
    past (each bucket "evicts against" itself).  The secondary control is
    to evict data before evicting metadata.

    Because of this bucketing, we may end up with one bucket mostly
    containing freed blocks that are very old, while another bucket has
    more recently accessed, still-allocated blocks.  Data in the useful
    bucket (with still-allocated blocks) may be evicted in preference to
    data in the useless bucket (with old, freed blocks).

    On dcenter, we saw that the MFU metadata bucket was 230MB, while the
    MFU data bucket was 27GB and the MRU metadata bucket was 256GB.
    However, the vast majority of data in the MRU metadata bucket (256GB)
    was freed blocks, and thus useless.  Meanwhile, the MFU metadata bucket
    (230MB) was constantly evicting useful blocks that will be soon needed.

    The problem of cache segmentation is a larger problem that needs more
    investigation.  However, if we stop caching freed blocks, it should
    reduce the impact of this more fundamental issue.

MFC after:	2 weeks
2013-06-08 09:11:20 +00:00
Xin LI
ca8a27d4b1 MFV r251474:
* Illumos zfs issue #3137 L2ARC compression

Whether or not to compress buffers entering the L2ARC is
controlled by "compression" setting on the dataset, when
compression is not "off", L2ARC compression is enabled.

The compress method is always LZ4 for L2ARC when enabled
because it works best for the scenario.

MFC after:	2 weeks
2013-06-06 23:21:41 +00:00
Mark Johnston
f263e440d4 SDT probes can directly pass up to five arguments as arguments to
dtrace_probe(). Arguments beyond these five must be obtained in an
architecture-specific way; this can be done through the getargval provider
method, and through dtrace_getarg() if getargval isn't overridden.

This change fixes two off-by-one bugs in the way these arguments are fetched
in FreeBSD's DTrace implementation. First, the SDT provider must set the
aframes parameter to 1 when creating a probe. The aframes parameter controls
the number of frames that dtrace_getarg() will step over in order to find
the frame containing the extra arguments. On FreeBSD, dtrace_getarg() is
called in SDT probe context via

dtrace_probe()->dtrace_dif_emulate()->dtrace_dif_variable->dtrace_getarg()

so aframes must be 3 since the arguments are in dtrace_probe()'s frame; it
was previously being called with a value of 2 instead. illumos uses a
different aframes value for SDT probes, but this is because illumos SDT
probes fire by triggering the #UD fault handler rather than calling
dtrace_probe() directly.

The second bug has to do with the way arguments are grabbed out
dtrace_probe()'s frame on amd64. The code currently jumps over the first
stack argument and retrieves the rest of them using a pointer into the
stack. This works on i386 because all of dtrace_probe()'s arguments will be
on the stack and the first argument is the probe ID, which should be
ignored. However, it is incorrect to ignore the first stack argument on
amd64, so we correct the pointer used to access the arguments.

MFC after:	2 weeks
2013-06-02 01:05:36 +00:00
Mark Johnston
18161786c6 Port the SDT test now that it's possible to create SDT probes that take
seven arguments.

The original test uses Solaris' uadmin system call to trigger the test
probe; this change adds a sysctl to the dtrace_test module and gets the test
program to trigger the test probe via the sysctl handler.

The test is currently failing on amd64 because of some bugs in the way that
probe arguments beyond the first five are obtained - these bugs will be
fixed in a separate change.
2013-06-02 00:33:36 +00:00
Mark Johnston
427bc75e19 The fasttrap provider cleans up probes asynchronously when a process with
USDT probes exits. This was previously done with a callout; however, it is
possible to sleep while holding the DTrace mutexes, so a panic will occur
on INVARIANTS kernels if the callout handler can't immediately acquire one
of these mutexes. This panic will be frequently triggered on systems where
a USDT-enabled program (perl, for instance) is often run.

This revision changes the fasttrap cleanup mechanism so that a dedicated
thread is used instead of a callout. The old behaviour is otherwise
preserved.

Reviewed by:	rpaulo
MFC after:	1 month
2013-05-24 03:29:32 +00:00
Mark Johnston
09e6105ff4 Bring back part of r249367 by adding DTrace's temporal option, which allows
users to guarantee that the output of DTrace scripts will be time-ordered.
This option is enabled by adding the line

  #pragma D option temporal

to the beginning of a script, or by adding '-x temporal' to the arguments of
dtrace(1).

This change fixes a bug in the original port of the temporal option. This
bug was causing some assertions to fail, so they had been disabled; in this
revision the assertions are working properly and are enabled.

The DTrace version number has been bumped from 1.9.0 to 1.9.1 to reflect
the language change that's being introduced.

This change corresponds to part of illumos-gate commit e5803b76927480:
  3021 option for time-ordered output from dtrace(1M)

Reviewed by:	pfg
Obtained from:	illumos
MFC after:	1 month
2013-05-12 16:26:33 +00:00
Davide Italiano
a28d25df31 In case ZFS doesn't use UMA for buffers there's no need to waste memory
creating zones that will remain empty.

Reviewed by:	pjd
2013-05-01 17:34:44 +00:00
Steven Hartland
562a9d583b Changed ZFS TRIM sysctl from vfs.zfs.trim_disable -> vfs.zfs.trim.enabled
Enabled ZFS TRIM by default

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-04-26 11:24:20 +00:00
Martin Matuska
95b6497f5e MFV r249857:
Merge vendor bugfix for a possible deadlock related to async destroy
and improve write performance by introducing a new lock protecting
tx_open_txg.

Illumos ZFS issues:
  3642 dsl_scan_active() should not issue I/O to determine if async
       destroying is active
  3643 txg_delay should not hold the tc_lock

MFC after:	1 week
2013-04-24 21:21:03 +00:00
Martin Matuska
90eafc0bb8 The zfs synctask code restructuring introduced a new bug that makes it
impossible to set quota and reservation on pools lower than version 22.
Problem has been reported and a solution discussed with vendor.

Illumos ZFS issues:
  3739 cannot set zfs quota or reservation on pool version < 22

Reviewed by:	Matthew Ahrens <mahrens@delphix.com>
Reported by:	Steve Wills <swills@FreeBSD.org>
MFC after:	3 days
2013-04-23 06:28:35 +00:00
Pedro F. Giffuni
03836978be DTrace: Revert r249367
The following change from illumos brought caused DTrace to
pause in an interactive environment:

3026 libdtrace should set LD_NOLAZYLOAD=1 to help the pid provider

This was not detected during testing because it doesn't
affect scripts.

We shouldn't be changing the environment, especially since the
LD_NOLAZYLOAD option doesn't apply to our (GNU) ld.
Unfortunately the change from upstream was made in such a way
that it is very difficult to separate this change from the
others so, at least for now, it's better to just revert
everything.

Reference:
https://www.illumos.org/issues/3026

Reported by:	Navdeep Parhar and Mark Johnston
2013-04-17 02:20:17 +00:00
Pedro F. Giffuni
ddd5b8e9b4 DTrace: option for time-ordered output
Merge changes from illumos:

3021 option for time-ordered output from dtrace(1M)
3022 DTrace: keys should not affect the sort order when sorting by value
3023 it should be possible to dereference dynamic variables
3024 D integer narrowing needs some work
3025 register leak in D code generation
3026 libdtrace should set LD_NOLAZYLOAD=1 to help the pid provider

This brings yet another feature implemented in upstream DTrace.
A complete description is available here:
http://dtrace.org/blogs/ahl/2012/07/28/my-new-dtrace-favorite/

This change bumps the DT_VERS_* number to 1.9.1 in
accordance to what is done in illumos.

This change was somewhat complicated because upstream is mixed many
changes in an individual commit and some of the tests don't really
apply to us.

There are also appear to be differences in timestamping with Solaris
so we had to workaround some assertions making sure no regression
happened.

Special thanks to Fabian Keil for changes and testing.

Illumos Revisions:	13758:23432da34147

Reference:
https://www.illumos.org/issues/3021
https://www.illumos.org/issues/3022
https://www.illumos.org/issues/3023
https://www.illumos.org/issues/3024
https://www.illumos.org/issues/3025
https://www.illumos.org/issues/1694

Tested by:	Fabian Keil
Obtained from:	Illumos
MFC after:	1 months
2013-04-11 16:24:36 +00:00
Martin Matuska
2cb0c5e424 MFV r249354:
Merge bugfixes accepted and integrated by vendor. Underlying problems
have been reported by us and fixed in r240942 and r249196.

Illumos ZFS issues:
  3645 dmu_send_impl: possibilty of pool hold leak
  3692 Panic on zfs receive of a recursive deduplicated stream

MFC after:	8 days
2013-04-11 07:40:30 +00:00
Martin Matuska
86161c3eeb Cast to (void *)(uintptr_t) on copyout and copyin of zfs_iocparm_t.zfs_cmd
MFC after:	9 days
2013-04-10 07:01:17 +00:00
Martin Matuska
83b4af1142 ZFS expects a copyout of zfs_cmd_t on an ioctl error. Our sys_ioctl()
doesn't copyout in this case.

To solve this issue a new struct zfs_iocparm_t is introduced consisting of:
- zfs_ioctl_version (future backwards compatibility purposes)
- user space pointer to zfs_cmd_t (copyin and copyout)
- size of zfs_cmd_t (verification purposes)

The copyin and copyout of zfs_cmd_t is now done the illumos (vendor) way
what makes porting of new changes easier and ensures correct behavior if
returning an error.

MFC after:	10 days
2013-04-09 22:27:44 +00:00
Martin Matuska
a548fef5dc MFV r249186:
Do not list read-only pools in zpool.cache
Reduce diff against vendor in unused vdev_disk.c

Illumos ZFS issues:
  3639 zpool.cache should skip over readonly pools
  3640 want automatic devid updates

MFC after:	1 week
2013-04-06 17:24:00 +00:00
Martin Matuska
95e7edacfe MFV r248660:
Merge vendor change - modify time processing in deadman thread.

Illumos ZFS issues:
  3618 ::zio dcmd does not show timestamp data

MFC after:	3 weeks
2013-04-06 17:15:47 +00:00
Martin Matuska
367437755d Provide a fix for kernel panic if receiving recursive deduplicated streams.
Problem reported to vendor.

Illumos ZFS issues:
  3692 Panic on zfs receive of a recursive deduplicated stream

MFC after:	2 weeks
2013-04-06 11:54:41 +00:00
Martin Matuska
f1b5c26470 MFV r248217:
Merge change from vendor to reduce diff only.
ZFS dtrace probes are not supported on FreeBSD yet.

Illumos ZFS issues:
  3598 want to dtrace when errors are generated in zfs

MFC after:	3 weeks
2013-04-06 10:39:38 +00:00
Martin Matuska
bae7bccf39 MFV r242816:
Import vendor change to reduce diff, no effect on FreeBSD.

Illumos ZFS issues:
  3517 importing pool with autoreplace=on and "hole" vdevs crashes syseventd
2013-04-06 08:21:37 +00:00
Andriy Gapon
9ff9b984c9 spa_open_common: fix argument to zvol_create_minors
Prior to r248571 spa_open was always called with a bare pool name,
but now it is called with a dataset name instead (spa_lookup handles
that).
So, when a ZFS root is mounted spa_open is called with a name of a root
dataset, which can very well be different from the pool name.
But zvol_create_minors should be called with the pool name, because it
performs a recursive traversal of all datasets under the name to find
all those that are volumes.

MFC after:	7 days
2013-04-03 11:06:26 +00:00
Martin Matuska
03863a70e1 Fix possible pool hold leak in dmu_send_impl()
Problem reported to vendor:
  https://www.illumos.org/issues/3645

Reported by:	Andriy Gapon <avg@FreeBSD.org>
MFC after:	15 days
2013-04-03 09:52:30 +00:00
Martin Matuska
41451f4a0e Do not check against uninitialized rc and comment out vendor code
MFC after:	16 days
2013-04-02 08:15:39 +00:00
Pedro F. Giffuni
9f4c7ba460 Dtrace: enablings on defunct providers prevent providers from unregistering
Merge change from illumos:

1368 enablings on defunct providers prevent providers from unregistering

We try to address some underlying differences between the Solaris
and FreeBSD implementations: dtrace_attach() / dtrace_detach() are
currently unimplemented in FreeBSD but the new code from illumos
makes use of taskq so some adaptations were made to dtrace_open()
and dtrace_close() to handle them appropriately.

Illumos Revision:	r13430:8e6add739e38

Reference:
https://www.illumos.org/issues/1368

Reviewed by:	gnn
Tested by:	Fabian Keil
Obtained from:	Illumos
MFC after:	3 weeks
2013-04-01 19:13:46 +00:00
Martin Matuska
20547d41f8 Call dmu_snapshot_list_next() in zvol.c with dsl_pool_config lock held
Submitted by:	Andriy Gapon <avg@FreeBSD.org>
MFC after:	17 days
2013-04-01 16:14:57 +00:00
Pedro F. Giffuni
f5678b698a Dtrace: dtrace.c erroneously checks for memory alignment on amd64.
Merge change from illumos:

3511 dtrace.c erroneously checks for memory alignment on amd64

Illumos Revision:	c93cc65

Reference:
https://www.illumos.org/issues/3511

Obtained from:	Illumos
MFC after:	3 weeks
2013-03-26 20:17:08 +00:00
Pedro F. Giffuni
5472787377 Dtrace: Add SUN MDB-like type-aware print() action.
Merge change from illumos:

1694 Add type-aware print() action

This is a very nice feature implemented in upstream Dtrace.
A complete description is available here:
http://dtrace.org/blogs/eschrock/2011/10/26/your-mdb-fell-into-my-dtrace/

This change bumps the DT_VERS_* number to 1.9.0 in
accordance to what is done in illumos.

While here also include some minor cleanups to ease further merging
and appease clang with a fix by Fabian Keil.

Illumos Revisions:	13501:c3a7090dbc16
			13483:f413e6c5d297

Reference:
https://www.illumos.org/issues/1560
https://www.illumos.org/issues/1694

Tested by:	Fabian Keil
Obtained from:	Illumos
MFC after:	1 month
2013-03-25 20:38:09 +00:00
Pedro F. Giffuni
730cecb05a Dtrace: add toupper()/tolower() and enhancements to lltostr().
Merge changes from illumos:

1451 DTrace needs toupper()/tolower() subroutines
1457 lltostr() D subroutine should take an optional base

This change bumps the DT_VERS_* number to 1.8.1 in
accordance to what is done in illumos.

The test suite we currently include is outdated and
doesnt support some updates in tst.subr.d which had to
be left out for now.

Illumos Revisions:	r13458 5e394d8db762
			r13459 c3454574dd1a

Reference:
https://www.illumos.org/issues/1451
https://www.illumos.org/issues/1457

Tested by:	Fabian Keil
Obtained from:	Illumos
MFC after:	1 month
2013-03-25 15:40:57 +00:00
Pedro F. Giffuni
f2e66d30b8 Dtrace: add optional size argument to tracemem().
Merge change from illumos:

1455 DTrace tracemem() should take an optional size argument

Our local enhancements to dt_print_bytes were equivalent to
those in illumos but we made it match the illumos version
to ease further code merges.

For now leave out tst.smallsize.d and tst.smallsize.d.out
since those don't seem to work cleanly on FreeBSD.

This change bumps the DT_VERS_* number to 1.7.1 in accordance
to what is done in illumos.

Illumos Revision:	13457:571b0355c2e3

Reference:
https://www.illumos.org/issues/1455

Tested by:	Fabian Keil
Obtained from:	Illumos
MFC after:	1 month
2013-03-24 19:12:08 +00:00
Will Andrews
58567a1b4e ZFS: Fix a panic while unmounting a busy filesystem.
This particular scenario was easily reproduced using a NFS export.  When the
first 'zfs unmount' occurred, it returned EBUSY via this path, while
vflush() had flushed references on the filesystem's root vnode, which in
turn caused its v_interlock to be destroyed.  The next time 'zfs unmount'
was called, vflush() tried to obtain this lock, which caused this panic.

Since vflush() on FreeBSD is a definitive call, there is no need to check
vfsp->vfs_count after it completes.  Simply #ifdef sun this check.

Submitted by:	avg
Reviewed by:	avg
Approved by:	ken (mentor)
MFC after:	1 month
2013-03-23 16:34:56 +00:00
Andriy Gapon
aaf2546b67 fbt_getargdesc: correctly handle types for return probes
MFC after:	6 days
2013-03-23 08:52:50 +00:00
Andriy Gapon
a47016e9a9 fbt_typoff_init: fix an off by one in determining required memory size
This issue would be silent most of the time, but if the requested memory
is a multiple of a page size, then accessing one element beyond the end
would lead to a kernel page fault.
Otherwise, the unlucky last type would just be inaccessible.

Reported by:	glebius
Tested by:	glebius
MFC after:	6 days
2013-03-23 08:48:44 +00:00
Steven Hartland
def84b9736 Fix for building libzpool under i386.
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 23:06:11 +00:00
Steven Hartland
2b114ad2a4 Add missing descriptions for ZFS sysctls
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 11:25:21 +00:00
Steven Hartland
adea827b21 Optimisation of TRIM processing.
Previously TRIM processing was very bursty. This was made worse by the fact
that TRIM requests on SSD's are typically much slower than reads or writes.
This often resulted in stalls while large numbers of TRIM's where processed.

In addition due to the way the TRIM thread was only woken by writes, deletes
could stall in the queue for extensive periods of time.

This patch adds a number of controls to how often the TRIM thread for each
SPA processes its outstanding delete requests.
vfs.zfs.trim.timeout: Delay TRIMs by up to this many seconds
vfs.zfs.trim.txg_delay: Delay TRIMs by up to this many TXGs (reduced to 32)
vfs.zfs.vdev.trim_max_bytes: Maximum pending TRIM bytes for a vdev
vfs.zfs.vdev.trim_max_pending: Maximum pending TRIM segments for a vdev
vfs.zfs.trim.max_interval: Maximum interval between TRIM queue processing
(seconds)

Given the most common TRIM implementation is ATA TRIM the current defaults
are targeted at that.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 11:02:08 +00:00
Steven Hartland
6ad46cec23 Names the ZFS TRIM thread
Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
MFC after:	2 weeks
2013-03-21 10:41:30 +00:00
Steven Hartland
89e5b43079 TRIM cache devices based on time instead of TXGs.
Currently, the trim module uses the same algorithm for data and cache
devices when deciding to issue TRIM requests, based on how far in the
past the TXG is.

Unfortunately, this is not ideal for cache devices, because the L2ARC
doesn't use the concept of TXGs at all. In fact, when using a pool for
reading only, the L2ARC is written but the TXG counter doesn't
increase, and so no new TRIM requests are issued to the cache device.

This patch fixes the issue by using time instead of the TXG number as
the criteria for trimming on cache devices. The basic delay principle
stays the same, but parameters are expressed in seconds instead of
TXGs. The new parameters are named trim_l2arc_limit and
trim_l2arc_batch, and both default to 30 second.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	17122c31ac
MFC after:	2 weeks
2013-03-21 10:29:05 +00:00
Steven Hartland
78ad0c1c80 Improve TXG handling in the TRIM module.
This patch adds some improvements to the way the trim module considers
TXGs:

 - Free ZIOs are registered with the TXG from the ZIO itself, not the
   current SPA syncing TXG (which may be out of date);
 - L2ARC are registered with a zero TXG number, as L2ARC has no concept
   of TXGs;
 - The TXG limit for issuing TRIMs is now computed from the last synced
   TXG, not the currently syncing TXG. Indeed, under extremely unlikely
   race conditions, there is a risk we could trim blocks which have been
   freed in a TXG that has not finished syncing, resulting in potential
   data corruption in case of a crash.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	5b46ad40d9
MFC after:	2 weeks
2013-03-21 10:16:10 +00:00
Steven Hartland
e07e3a3792 Don't register repair writes in the trim map.
The trim map inflight writes tree assumes non-conflicting writes, i.e.
that there will never be two simultaneous write I/Os to the same range
on the same vdev. This seemed like a sane assumption; however, in
actual testing, it appears that repair I/Os can very well conflict
with "normal" writes.

I'm not quite sure if these conflicting writes are supposed to happen
or not, but in the mean time, let's ignore repair writes for now. This
should be safe considering that, by definition, we never repair blocks
that are freed.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	Source: 6a3cebaf7c
2013-03-21 10:02:32 +00:00
Steven Hartland
e05aad2d33 Add TRIM support for L2ARC.
This adds TRIM support to cache vdevs. When ARC buffers are removed
from the L2ARC in arc_hdr_destroy(), arc_release() or l2arc_evict(),
the size previously occupied by the buffer gets scheduled for TRIMming.
As always, actual TRIMs are only issued to the L2ARC after
txg_trim_limit.

Reviewed by:	pjd (mentor)
Approved by:	pjd (mentor)
Obtained from:	31aae37399
MFC after:	2 weeks
2013-03-21 09:34:41 +00:00
Martin Matuska
192d547574 Release hold on pool before calling zvol_create_minor() 2013-03-20 09:56:20 +00:00
Martin Matuska
a0abc0d302 Run zvol_create_minors() only if in non-error case 2013-03-19 22:27:15 +00:00
Martin Matuska
e56718d734 Run zvol_create_minors() on snapshot creation 2013-03-19 22:14:50 +00:00
Martin Matuska
07091d8f14 MFV r247580:
Merge synctask code restructuring from vendor.

Modify forward and backward compatibility to support new change.

Illumos ZFS issues:
  3464 zfs synctask code needs restructuring

Sponsored by:	Hybrid Logic Ltd.
2013-03-19 12:51:18 +00:00
Martin Matuska
520268fb97 MFC @248493 2013-03-19 11:09:15 +00:00
Martin Matuska
87a5cb4650 Plug memory leak in dsl_check_snap_cb()
This was unnoticed because the function is very rarely used.

MFC after:	3 days
2013-03-19 07:47:51 +00:00
Martin Matuska
a602517b63 Add missing zvol_create_mirrors() on zfs_ioc_create() 2013-03-18 20:22:40 +00:00
John Baldwin
3cf3b9f097 Partially revert r195702. Deferring stops is now implemented via a set of
calls to toggle TDF_SBDRY rather than passing PBDRY to individual sleep
calls.
- Remove the stop_allowed parameters from cursig() and issignal().
  issignal() checks TDF_SBDRY directly.
- Remove the PBDRY and SLEEPQ_STOP_ON_BDRY flags.
2013-03-18 17:23:58 +00:00
Martin Matuska
876a84e867 MFC @248461 2013-03-18 09:39:51 +00:00
Martin Matuska
6f4accc2de Move common zfs ioctl compatibility functions (userland) into libzfs_compat.c
Introduce additional constants for zfs ioctl versions
2013-03-18 09:32:29 +00:00
Justin Hibbits
80a5635c8b Add FBT for PowerPC DTrace. Also, clean up the DTrace assembly code,
much of which is not necessary for PowerPC.

The FBT module can likely be factored into 3 separate files: common,
intel, and powerpc, rather than duplicating most of the code between
the x86 and PowerPC flavors.

All DTrace modules for PowerPC will be MFC'd together once Fasttrap is
completed.
2013-03-18 05:30:18 +00:00
Martin Matuska
af2e40ccd1 Merge libzfs_core part of r239388
Illumos ZFS issues:
  3085 zfs diff panics, then panics in a loop on booting

References:
  https://www.illumos.org/issues/3085
2013-03-17 18:49:11 +00:00
Martin Matuska
70b0720877 Fix accidentially changed ioc variable for old v15 compatibility 2013-03-17 17:28:06 +00:00
Martin Matuska
6cf922c88b Fix typo in sysctl description
Reported by:	Jeremy Chadwick
MFC after:	3 days
2013-03-17 15:53:27 +00:00
Martin Matuska
e2b4467975 libzfs_core:
- provide complete backwards compatibility (old utility, new kernel)
  - add zfs_cmd_t compatibility mapping in both directions
  - determine ioctl address in zfs_ioctl_compat.c
2013-03-17 10:57:04 +00:00
Martin Matuska
4f33cfb284 Initialize "error" variable where illumos does. 2013-03-16 20:28:38 +00:00
Martin Matuska
a03fbc7ecf MFC @248093 2013-03-09 11:57:51 +00:00
Attilio Rao
89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
Attilio Rao
c934116100 Merge from vmc-playground:
Introduce a new KPI that verifies if the page cache is empty for a
specified vm_object.  This KPI does not make assumptions about the
locking in order to be used also for building assertions at init and
destroy time.
It is mostly used to hide implementation details of the page cache.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	alc (vm_radix based version)
Tested by:	flo, pho, jhb, davide
2013-03-09 02:05:29 +00:00
Martin Matuska
91edf37414 Comment out unfeasible illumos copyin code and restore previous behavior. 2013-03-07 23:45:16 +00:00
Martin Matuska
b3b6851c78 Add missing init functions
Reduce diff to illumos
2013-03-06 11:33:25 +00:00
Xin LI
2f79ac7f21 Diff reduction with Illumos 2013-03-06 01:21:56 +00:00
Xin LI
227d24fc59 Use adx2 instead of adx in the second vsprintf, this fixes a
panic.
2013-03-05 22:58:53 +00:00
Martin Matuska
400c4069a5 MFV r247845:
Import ZFS bpobj bugfix from vendor.

Illumos ZFS issues:
  3603 panic from bpobj_enqueue_subobj()
  3604 zdb should print bpobjs more verbosely

References:
  https://www.illumos.org/issues/3603
  https://www.illumos.org/issues/3604

MFC after:	1 week
2013-03-05 18:54:41 +00:00
Martin Matuska
dce1a726f2 WiP merge of libzfs_core (MFV r238590, r238592)
not yet working, ioctl handling needs to be changed
2013-03-05 08:09:53 +00:00
Justin T. Gibbs
7e2a739f03 Fix assertion failure when using userland DTrace probes from
the pid provider on a kernel compiled with INVARIANTS.

sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c:
	In fasttrap_probe_pid(), attempts to write to the
	address space of the thread that fired the probe
	must be performed with the process of the thread
	held.  Use _PHOLD() to ensure this is the case.

	In fasttrap_probe_pid(), use proc_write_regs() instead
	of calling set_regs() directly.  proc_write_regs()
	performs invariant checks to verify the calling
	environment of set_regs().  PROC_LOCK()/UNLOCK() around
	the call to proc_write_regs() so that it's invariants
	are satisfied.

Sponsored by:	Spectra Logic Corporation
Reviewed by:	gnn, rpaulo
MFC after:	1 week
2013-03-04 22:07:36 +00:00
Rui Paulo
e0dffa2de2 Remove the extra parenthesis from the cv_init() macro. They are not
necessary because we already use parenthesis in zfs_cv_init().

This fixes a long standing bug where there would be an extra ")" at the
end of the string. This extra parenthesis would show up in the WCHAN of
the process (top, stty status, etc.).
2013-03-03 06:42:36 +00:00
Pawel Jakub Dawidek
2609222ab4 Merge Capsicum overhaul:
- Capability is no longer separate descriptor type. Now every descriptor
  has set of its own capability rights.

- The cap_new(2) system call is left, but it is no longer documented and
  should not be used in new code.

- The new syscall cap_rights_limit(2) should be used instead of
  cap_new(2), which limits capability rights of the given descriptor
  without creating a new one.

- The cap_getrights(2) syscall is renamed to cap_rights_get(2).

- If CAP_IOCTL capability right is present we can further reduce allowed
  ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
  ioctls can be retrived with cap_ioctls_get(2) syscall.

- If CAP_FCNTL capability right is present we can further reduce fcntls
  that can be used with the new cap_fcntls_limit(2) syscall and retrive
  them with cap_fcntls_get(2).

- To support ioctl and fcntl white-listing the filedesc structure was
  heavly modified.

- The audit subsystem, kdump and procstat tools were updated to
  recognize new syscalls.

- Capability rights were revised and eventhough I tried hard to provide
  backward API and ABI compatibility there are some incompatible changes
  that are described in detail below:

	CAP_CREATE old behaviour:
	- Allow for openat(2)+O_CREAT.
	- Allow for linkat(2).
	- Allow for symlinkat(2).
	CAP_CREATE new behaviour:
	- Allow for openat(2)+O_CREAT.

	Added CAP_LINKAT:
	- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
	- Allow to be target for renameat(2).

	Added CAP_SYMLINKAT:
	- Allow for symlinkat(2).

	Removed CAP_DELETE. Old behaviour:
	- Allow for unlinkat(2) when removing non-directory object.
	- Allow to be source for renameat(2).

	Removed CAP_RMDIR. Old behaviour:
	- Allow for unlinkat(2) when removing directory.

	Added CAP_RENAMEAT:
	- Required for source directory for the renameat(2) syscall.

	Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
	- Allow for unlinkat(2) on any object.
	- Required if target of renameat(2) exists and will be removed by this
	  call.

	Removed CAP_MAPEXEC.

	CAP_MMAP old behaviour:
	- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
	  PROT_WRITE.
	CAP_MMAP new behaviour:
	- Allow for mmap(2)+PROT_NONE.

	Added CAP_MMAP_R:
	- Allow for mmap(PROT_READ).
	Added CAP_MMAP_W:
	- Allow for mmap(PROT_WRITE).
	Added CAP_MMAP_X:
	- Allow for mmap(PROT_EXEC).
	Added CAP_MMAP_RW:
	- Allow for mmap(PROT_READ | PROT_WRITE).
	Added CAP_MMAP_RX:
	- Allow for mmap(PROT_READ | PROT_EXEC).
	Added CAP_MMAP_WX:
	- Allow for mmap(PROT_WRITE | PROT_EXEC).
	Added CAP_MMAP_RWX:
	- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).

	Renamed CAP_MKDIR to CAP_MKDIRAT.
	Renamed CAP_MKFIFO to CAP_MKFIFOAT.
	Renamed CAP_MKNODE to CAP_MKNODEAT.

	CAP_READ old behaviour:
	- Allow pread(2).
	- Disallow read(2), readv(2) (if there is no CAP_SEEK).
	CAP_READ new behaviour:
	- Allow read(2), readv(2).
	- Disallow pread(2) (CAP_SEEK was also required).

	CAP_WRITE old behaviour:
	- Allow pwrite(2).
	- Disallow write(2), writev(2) (if there is no CAP_SEEK).
	CAP_WRITE new behaviour:
	- Allow write(2), writev(2).
	- Disallow pwrite(2) (CAP_SEEK was also required).

	Added convinient defines:

	#define	CAP_PREAD		(CAP_SEEK | CAP_READ)
	#define	CAP_PWRITE		(CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_R		(CAP_MMAP | CAP_SEEK | CAP_READ)
	#define	CAP_MMAP_W		(CAP_MMAP | CAP_SEEK | CAP_WRITE)
	#define	CAP_MMAP_X		(CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
	#define	CAP_MMAP_RW		(CAP_MMAP_R | CAP_MMAP_W)
	#define	CAP_MMAP_RX		(CAP_MMAP_R | CAP_MMAP_X)
	#define	CAP_MMAP_WX		(CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_MMAP_RWX		(CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
	#define	CAP_RECV		CAP_READ
	#define	CAP_SEND		CAP_WRITE

	#define	CAP_SOCK_CLIENT \
		(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
		 CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
	#define	CAP_SOCK_SERVER \
		(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
		 CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
		 CAP_SETSOCKOPT | CAP_SHUTDOWN)

	Added defines for backward API compatibility:

	#define	CAP_MAPEXEC		CAP_MMAP_X
	#define	CAP_DELETE		CAP_UNLINKAT
	#define	CAP_MKDIR		CAP_MKDIRAT
	#define	CAP_RMDIR		CAP_UNLINKAT
	#define	CAP_MKFIFO		CAP_MKFIFOAT
	#define	CAP_MKNOD		CAP_MKNODAT
	#define	CAP_SOCK_ALL		(CAP_SOCK_CLIENT | CAP_SOCK_SERVER)

Sponsored by:	The FreeBSD Foundation
Reviewed by:	Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with:	rwatson, benl, jonathan
ABI compatibility discussed with:	kib
2013-03-02 00:53:12 +00:00
Xin LI
5c737b11df MFV r247575:
Import a fix tighten assertion on SPA versions from vendor (Illumos).

Illumos ZFS issue:

  3543 Feature flags causes assertion in spa.c to miss certain cases

MFC after:	2 weeks
2013-03-01 22:20:13 +00:00
Martin Matuska
4abd59512a MFV r247316:
Merge new read-only zfs properties from vendor (illumos)

Illumos ZFS issues:
  3588 provide zfs properties for logical (uncompressed) space used and
       referenced

References:
  https://www.illumos.org/issues/3588

MFC after:	2 weeks
2013-03-01 21:58:51 +00:00
Martin Matuska
bb508e7732 Fix the zfs_ioctl compat layer to support zfs_cmd size change introduced
in r247265 (ZFS deadman thread). Both new utilities now support the old
kernel and new kernel properly detects old utilities.

For future backwards compatibility, the vfs.zfs.version.ioctl read-only
sysctl has been introduced. With this sysctl zfs utilities will be able
to detect the ioctl interface version of the currently loaded zfs module.

As a side effect, the zfs utilities between r247265 and this revision don't
support the old kernel module. If you are using HEAD newer or equal than
r247265, install the new kernel module (or whole kernel) first.

MFC after:	10 days
2013-03-01 09:42:58 +00:00
Martin Matuska
24245e76ea MFV 247176, 247178, 247315:
Import metaslab_sync() speedup from vendor (illumos).

Illumos ZFS issues:
  3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
  3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not
       condensing)
  3578 transferring the freed map to the defer map should be constant time
  3579 ztest trips assertion in metaslab_weight()

References:
  https://www.illumos.org/issues/3552
  https://www.illumos.org/issues/3564
  https://www.illumos.org/issues/3578
  https://www.illumos.org/issues/3579

MFC after:	2 weeks
2013-02-27 14:45:23 +00:00
Martin Matuska
e4428d63a8 Be more verbose on ZFS deadman I/O panic
Patch suggested upstream.

Suggested by:	Olivier Cinquin
MFC after:	12 days
2013-02-26 20:41:27 +00:00
Martin Matuska
e70664bafc MFV v242732:
Merge the ZFS I/O deadman thread from vendor (illumos).
This feature panics the system on hanging ZFS I/O, helps debugging
and resumes failed service.

The panic behavior can be controlled with the loader-only tunables:
vfs.zfs.deadman_enabled (enable or disable panic on stalled ZFS I/O)
vfs.zfs.deadman_synctime (expiration time for stalled ZFS I/O)

By default, ZFS I/O deadman is enabled by default on amd64 and i386
excluding virtual guest machines.

Illumos ZFS issues:
  3246 ZFS I/O deadman thread

References:
  https://www.illumos.org/issues/3246

MFC after:	2 weeks
2013-02-25 12:33:31 +00:00
Martin Matuska
781c0f87d3 MFV r246653:
Import vendor change to avoid "unitialized variable" warnings.

Illumos ZFS issues:
  3522 zfs module should not allow uninitialized variables

References:
  https://www.illumos.org/issues/3522
2013-02-23 11:21:05 +00:00
Justin T. Gibbs
6a8f90edf5 Avoid panic when tearing down the DTrace pid provider for a
process that has crashed.

sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c:
	In fasttrap_pid_disable(), we cannot PHOLD the proc
	structure for a process that no longer exists, but
	we still have other, fasttrap specific, state that
	must be cleaned up for probes that existed in the
	dead process.  Instead of returning early if the
	process related to our probes isn't found,
	conditionalize the locking and carry on with a NULL
	proc pointer.  The rest of the fasttrap code already
	understands that a NULL proc is possible and does
	the right things in this case.

Sponsored by:	Spectra Logic Corporation
Reviewed by:	rpaulo, gnn
MFC after:	1 week
2013-02-20 17:55:17 +00:00
Xin LI
e469d5a70f Eliminate real_LZ4_uncompress. It's unused and does not perform sufficient
check against input stream (i.e. it could read beyond specified input
buffer).
2013-02-14 21:02:18 +00:00
Martin Matuska
7c695febc9 Change vfs.zfs.write_to_degraded from CTLFLAG_RW to CTLFLAG_RWTUN
Suggested by:	pjd
2013-02-13 23:11:25 +00:00
Xin LI
314caba11c Restore De Bruijn algorithm for sparc64 where the compiler rely on a
library function for __builtin_c?z.

Tested by:	Michael Moll <kvedulv kvedulv de>
2013-02-13 17:30:54 +00:00
Martin Matuska
6a33bbc041 Merge zfs_ioctl.c code that should have been merged together with ZFS v28.
Fixes several problems if working with read-only pools.

Changed code originaly introduced in onnv-gate 13061:bda0decf867b
Contains changes up to illumos-gate 13700:4bc0783f6064

PR:		kern/175897
Suggested by:	avg

MFC after:	2 weeks
2013-02-11 21:10:55 +00:00
Martin Matuska
9689178c3f MFV r246633:
Import vendor bugfixes regarding SA rounding, header size and layout.
This was already partially fixed by avg.

Illumos ZFS issues:
  3512 rounding discrepancy in sa_find_sizes()
  3513 mismatch between SA header size and layout

References:
  https://www.illumos.org/issues/3512
  https://www.illumos.org/issues/3513

MFC after:	2 weeks
2013-02-11 14:29:38 +00:00
Martin Matuska
bb03847418 MFV r246394:
Add tunable to allow block allocation on degraded vdevs.

Illumos ZFS issues:
  3507 Tunable to allow block allocation even on degraded vdevs

References:
  https://www.illumos.org/issues/3507

MFC after:	2 weeks
2013-02-11 13:59:57 +00:00
Martin Matuska
ff20578569 MFV r246392:
Import vendor ZFS bugfix fixing a possible deadlock in arc_read().

Illumos ZFS issues:
  3498 panic in arc_read(): !refcount_is_zero(&pbuf->b_hdr->b_refcnt)

References:
  https://www.illumos.org/issues/3498

MFC after:	2 weeks
2013-02-11 12:42:11 +00:00
Martin Matuska
8a2dc7faae MFV r246390:
Import minor type change in refcount.h header from vendor (illumos).

MFC after:	2 weeks
2013-02-11 07:48:57 +00:00
Martin Matuska
fd9778c236 MFV r246388:
Import vendor bugfixes

Illumos ZFS issues:
  3422 zpool create/syseventd race yield non-importable pool
  3425 first write to a new zvol can fail with EFBIG

References:
  https://www.illumos.org/issues/3422
  https://www.illumos.org/issues/3425

MFC after:	2 weeks
2013-02-10 19:32:55 +00:00
Xin LI
ef17620fc8 MFV r245512:
* Illumos zfs issue #3035 [1] LZ4 compression support in ZFS.

LZ4 is a new high-speed BSD-licensed compression algorithm created
by Yann Collet that delivers very high compression and decompression
performance compared to lzjb (>50% faster on compression, >80% faster
on decompression and around 3x faster on compression of incompressible
data), while giving better compression ratio [1].

This version of LZ4 corresponds to upstream's [2] revision 85.

Please note that for obvious reasons this is not backward read
compatible.  This means once a pool have LZ4 compressed data, these
data can no longer be read by older ZFS implementations.

Local changes:

 - On-stack hash table disabled and using kernel slab allocator
   instead, at this time.  This requires larger kernel thread stack
   for zio workers.  This may change in the future should we adjusted
   the zio workers' thread stack size.
 - likely and unlikely will be undefined if they are already defined,
   this is required for i386 XEN build.
 - Removed De Bruijn sequence based __builtin_ctz family of builtins
   in favor of the latter.  Both GCC and clang supports these builtins.
 - Changed the way the LZ4 code detects endianness.
 - Manual pages modifications to mention the feature based on Illumos
   counterpart.
 - Boot loader changes to make it support LZ4 decompression.

[1] https://www.illumos.org/issues/3035
[2] http://code.google.com/p/lz4/source/list

Obtained from:	Illumos (13921:9d721847e469)
Tested on:	FreeBSD/amd64
MFC after:	1 month
2013-02-09 06:39:28 +00:00
Sergey Kandaurov
3c56b4f165 Fix warning: comparison of unsigned expression < 0 is always false.
Reported by:	clang
2013-02-08 09:54:53 +00:00
Andriy Gapon
0dcab786b8 zfs_vget, zfs_fhtovp: properly handle the z_shares_dir object
A special gfs vnode corresponds to that object.
A regular zfs vnode must not be returned.

This should be upstreamed.

Reported by:	pluknet
Submitted by:	rmacklem
Tested by:	pluknet
MFC after:	10 days
2013-02-08 07:49:54 +00:00
Andriy Gapon
e2bb19dce5 zfs: update comments about zfid_long_t to match the FreeBSD definitions
MFC after:	1 week
2013-02-08 07:44:15 +00:00
Andriy Gapon
c7d346f269 zfs: fix, improve and re-organize page_lookup and page_unlock
Now they are split into two pairs: page_hold/page_unhold for mappedread
and page_busy/page_unbusy for update_pages.

For mappedread we simply hold a page that is to be used as a source if it
is resident and valid (and not busy).  This is sufficient since we are
only doing page -> user buffer copying.  There is no page <-> backing
storage I/O involved.

update_pages is now better split to properly handle the putpages case
(page -> arc) and the regular write case (arc -> page).

For the latter we use complete protocol of marking an object with
paging-in-progress and marking a page with io_start (busy count).
Also, in this case we remove the write bit from all page mappings and
clear dirty bits of the pages, the former is needed to ensure that the
latter does the right thing.
Additionally we update a page if it is cached instead of just freeing it
as was done before.  This needs to be verified.

A minor detail: ZFS-backed pages should always be either fully valid
or fully invalid.  Assert this and use simpler API that does not deal
with sub-page blocks.

Reviewed by:	kib
MFC after:	26 days
2013-02-03 18:42:20 +00:00
Justin Hibbits
7e7a9efdb5 Fix the PowerPC DTrace copy functions. The kernel doesn't hold the same view to
the user map, so use the md copy in/out functions provided by the kernel.

MFC with:	r242723
2013-02-03 00:19:34 +00:00
Andriy Gapon
5583e07188 solaris compat: remove KM_ZERO
- there is no such flag in Solaris and derivatives
- the flag was added in an unrelated change
- the flag is not used

The proper way to allocate zeroed out memory is to use kmem_zalloc.

MFC after:	3 days
2013-02-02 11:41:05 +00:00
Andriy Gapon
13235aaa89 zfs: add MODULE_VERSION for zfsctrl
This should allow the kernel linker to easily detect a situation
when the module is present both in a kernel and in a preloaded file
(zfs.ko).

Reviewed by:	jhb
MFC after:	5 days
2013-02-02 11:35:18 +00:00
Andriy Gapon
ea84c62f93 spa_generate_rootconf: add support for old vdev labels
It seems that old ZFS versions (v15) completely omit "vdev_children"
property when there is a single child.

Reported by:	jase
Tested by:	jase
MFC after:	1 week
2013-01-26 10:34:17 +00:00
Xin LI
5c74885e99 MFV r245510:
improve the comment in txg.c

Obtained from:	Illumos (13910:f3454e0a097c)
MFC after:	2 weeks
2013-01-16 22:59:50 +00:00
Konstantin Belousov
614b9f9130 For zfs vnodes, use the standard inode number based hash algorithm.
Reviewed and tested by:	peter
Sponsored by:	The FreeBSD Foundation
MFC after:	5 days
2013-01-14 05:45:33 +00:00
Xin LI
290a1ba9a4 The current ZFS code expects ddt_zap_count to always succeed by asserting
the underlying zap_count() to return no errors.  However, it is possible
that the pool reaches to such a state where zap_count would return error,
leading to panics when a pool is imported.

This commit changes the ddt_zap_count to return error returned from
zap_count and handle the error appropriately.  With this change, it's now
possible to let zpool rollback damaged transaction groups and import the
pool.

Obtained from:	ZFS on Linux github (e8fd45a0f9)
MFC after:	1 month
2013-01-10 19:26:56 +00:00
Andriy Gapon
f71fbb1d12 zfs: solaris doesn't have KM_ZERO, kmem_zalloc should be used instead
To do:		remove KM_ZERO declaration
Pointyhat to:	avg (for mindlessly using the pseudo-flag)
MFC after:	instantly (to fix stable/8 build)
2012-12-23 19:58:41 +00:00
Ryan Stone
6969ef6656 Correct a series of errors in the hand-rolled locking for drace_debug.c:
- Use spinlock_enter()/spinlock_exit() to prevent a thread holding a
  debug lock from being preempted to prevent other threads waiting
  on that lock from starvation.

- Handle the possibility of CPU migration in between the fetch of curcpu
  and the call to spinlock_enter() by saving curcpu in a local variable.

- Use memory barriers to prevent reordering of loads and stores of the
  data protected by the lock outside of the critical section

- Eliminate false sharing of the locks by moving them into the structures
  that they protect and aligning them to a cacheline boundary.

- Record the owning thread in the lock to make debugging future problems
  easier.

Reviewed by:	rpaulo (initial version)
MFC after:	2 weeks
2012-12-23 15:50:37 +00:00