ZFS event processing should work on R/O root filesystems
Illumos ZFS issues:
3749 zfs event processing should work on R/O root filesystems
MFC after: 2 weeks
* 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
* 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
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
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.
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
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
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
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
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
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/3021https://www.illumos.org/issues/3022https://www.illumos.org/issues/3023https://www.illumos.org/issues/3024https://www.illumos.org/issues/3025https://www.illumos.org/issues/1694
Tested by: Fabian Keil
Obtained from: Illumos
MFC after: 1 months
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
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
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
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
Import vendor change to reduce diff, no effect on FreeBSD.
Illumos ZFS issues:
3517 importing pool with autoreplace=on and "hole" vdevs crashes syseventd
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
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
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/1560https://www.illumos.org/issues/1694
Tested by: Fabian Keil
Obtained from: Illumos
MFC after: 1 month
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/1451https://www.illumos.org/issues/1457
Tested by: Fabian Keil
Obtained from: Illumos
MFC after: 1 month
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
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
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
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
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
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
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
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
