commit 50c957f702
Author: Ned Bass <bass6@llnl.gov>
Date: Wed Mar 16 18:25:34 2016 -0700
Implement large_dnode pool feature
Justification
-------------
This feature adds support for variable length dnodes. Our motivation is
to eliminate the overhead associated with using spill blocks. Spill
blocks are used to store system attribute data (i.e. file metadata) that
does not fit in the dnode's bonus buffer. By allowing a larger bonus
buffer area the use of a spill block can be avoided. Spill blocks
potentially incur an additional read I/O for every dnode in a dnode
block. As a worst case example, reading 32 dnodes from a 16k dnode block
and all of the spill blocks could issue 33 separate reads. Now suppose
those dnodes have size 1024 and therefore don't need spill blocks. Then
the worst case number of blocks read is reduced to from 33 to two--one
per dnode block. In practice spill blocks may tend to be co-located on
disk with the dnode blocks so the reduction in I/O would not be this
drastic. In a badly fragmented pool, however, the improvement could be
significant.
ZFS-on-Linux systems that make heavy use of extended attributes would
benefit from this feature. In particular, ZFS-on-Linux supports the
xattr=sa dataset property which allows file extended attribute data
to be stored in the dnode bonus buffer as an alternative to the
traditional directory-based format. Workloads such as SELinux and the
Lustre distributed filesystem often store enough xattr data to force
spill bocks when xattr=sa is in effect. Large dnodes may therefore
provide a performance benefit to such systems.
Other use cases that may benefit from this feature include files with
large ACLs and symbolic links with long target names. Furthermore,
this feature may be desirable on other platforms in case future
applications or features are developed that could make use of a
larger bonus buffer area.
Implementation
--------------
The size of a dnode may be a multiple of 512 bytes up to the size of
a dnode block (currently 16384 bytes). A dn_extra_slots field was
added to the current on-disk dnode_phys_t structure to describe the
size of the physical dnode on disk. The 8 bits for this field were
taken from the zero filled dn_pad2 field. The field represents how
many "extra" dnode_phys_t slots a dnode consumes in its dnode block.
This convention results in a value of 0 for 512 byte dnodes which
preserves on-disk format compatibility with older software.
Similarly, the in-memory dnode_t structure has a new dn_num_slots field
to represent the total number of dnode_phys_t slots consumed on disk.
Thus dn->dn_num_slots is 1 greater than the corresponding
dnp->dn_extra_slots. This difference in convention was adopted
because, unlike on-disk structures, backward compatibility is not a
concern for in-memory objects, so we used a more natural way to
represent size for a dnode_t.
The default size for newly created dnodes is determined by the value of
a new "dnodesize" dataset property. By default the property is set to
"legacy" which is compatible with older software. Setting the property
to "auto" will allow the filesystem to choose the most suitable dnode
size. Currently this just sets the default dnode size to 1k, but future
code improvements could dynamically choose a size based on observed
workload patterns. Dnodes of varying sizes can coexist within the same
dataset and even within the same dnode block. For example, to enable
automatically-sized dnodes, run
# zfs set dnodesize=auto tank/fish
The user can also specify literal values for the dnodesize property.
These are currently limited to powers of two from 1k to 16k. The
power-of-2 limitation is only for simplicity of the user interface.
Internally the implementation can handle any multiple of 512 up to 16k,
and consumers of the DMU API can specify any legal dnode value.
The size of a new dnode is determined at object allocation time and
stored as a new field in the znode in-memory structure. New DMU
interfaces are added to allow the consumer to specify the dnode size
that a newly allocated object should use. Existing interfaces are
unchanged to avoid having to update every call site and to preserve
compatibility with external consumers such as Lustre. The new
interfaces names are given below. The versions of these functions that
don't take a dnodesize parameter now just call the _dnsize() versions
with a dnodesize of 0, which means use the legacy dnode size.
New DMU interfaces:
dmu_object_alloc_dnsize()
dmu_object_claim_dnsize()
dmu_object_reclaim_dnsize()
New ZAP interfaces:
zap_create_dnsize()
zap_create_norm_dnsize()
zap_create_flags_dnsize()
zap_create_claim_norm_dnsize()
zap_create_link_dnsize()
The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The
spa_maxdnodesize() function should be used to determine the maximum
bonus length for a pool.
These are a few noteworthy changes to key functions:
* The prototype for dnode_hold_impl() now takes a "slots" parameter.
When the DNODE_MUST_BE_FREE flag is set, this parameter is used to
ensure the hole at the specified object offset is large enough to
hold the dnode being created. The slots parameter is also used
to ensure a dnode does not span multiple dnode blocks. In both of
these cases, if a failure occurs, ENOSPC is returned. Keep in mind,
these failure cases are only possible when using DNODE_MUST_BE_FREE.
If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0.
dnode_hold_impl() will check if the requested dnode is already
consumed as an extra dnode slot by an large dnode, in which case
it returns ENOENT.
* The function dmu_object_alloc() advances to the next dnode block
if dnode_hold_impl() returns an error for a requested object.
This is because the beginning of the next dnode block is the only
location it can safely assume to either be a hole or a valid
starting point for a dnode.
* dnode_next_offset_level() and other functions that iterate
through dnode blocks may no longer use a simple array indexing
scheme. These now use the current dnode's dn_num_slots field to
advance to the next dnode in the block. This is to ensure we
properly skip the current dnode's bonus area and don't interpret it
as a valid dnode.
zdb
---
The zdb command was updated to display a dnode's size under the
"dnsize" column when the object is dumped.
For ZIL create log records, zdb will now display the slot count for
the object.
ztest
-----
Ztest chooses a random dnodesize for every newly created object. The
random distribution is more heavily weighted toward small dnodes to
better simulate real-world datasets.
Unused bonus buffer space is filled with non-zero values computed from
the object number, dataset id, offset, and generation number. This
helps ensure that the dnode traversal code properly skips the interior
regions of large dnodes, and that these interior regions are not
overwritten by data belonging to other dnodes. A new test visits each
object in a dataset. It verifies that the actual dnode size matches what
was stored in the ztest block tag when it was created. It also verifies
that the unused bonus buffer space is filled with the expected data
patterns.
ZFS Test Suite
--------------
Added six new large dnode-specific tests, and integrated the dnodesize
property into existing tests for zfs allow and send/recv.
Send/Receive
------------
ZFS send streams for datasets containing large dnodes cannot be received
on pools that don't support the large_dnode feature. A send stream with
large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be
unrecognized by an incompatible receiving pool so that the zfs receive
will fail gracefully.
While not implemented here, it may be possible to generate a
backward-compatible send stream from a dataset containing large
dnodes. The implementation may be tricky, however, because the send
object record for a large dnode would need to be resized to a 512
byte dnode, possibly kicking in a spill block in the process. This
means we would need to construct a new SA layout and possibly
register it in the SA layout object. The SA layout is normally just
sent as an ordinary object record. But if we are constructing new
layouts while generating the send stream we'd have to build the SA
layout object dynamically and send it at the end of the stream.
For sending and receiving between pools that do support large dnodes,
the drr_object send record type is extended with a new field to store
the dnode slot count. This field was repurposed from unused padding
in the structure.
ZIL Replay
----------
The dnode slot count is stored in the uppermost 8 bits of the lr_foid
field. The bits were unused as the object id is currently capped at
48 bits.
Resizing Dnodes
---------------
It should be possible to resize a dnode when it is dirtied if the
current dnodesize dataset property differs from the dnode's size, but
this functionality is not currently implemented. Clearly a dnode can
only grow if there are sufficient contiguous unused slots in the
dnode block, but it should always be possible to shrink a dnode.
Growing dnodes may be useful to reduce fragmentation in a pool with
many spill blocks in use. Shrinking dnodes may be useful to allow
sending a dataset to a pool that doesn't support the large_dnode
feature.
Feature Reference Counting
--------------------------
The reference count for the large_dnode pool feature tracks the
number of datasets that have ever contained a dnode of size larger
than 512 bytes. The first time a large dnode is created in a dataset
the dataset is converted to an extensible dataset. This is a one-way
operation and the only way to decrement the feature count is to
destroy the dataset, even if the dataset no longer contains any large
dnodes. The complexity of reference counting on a per-dnode basis was
too high, so we chose to track it on a per-dataset basis similarly to
the large_block feature.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3542
Leading '+', '-', and ':' in optstring have special meaning. We briefly
mention that the first two have special meaning in that we say
POSIXLY_CORRECT turns them off, but we don't actually document their
meaning. Add a paragraph to RETURN VALUES explaining how they control
the treatment of non-option arguments.
A leading ':' has no mention; add a note that it suppresses warnings about
missing arguments.
Reviewed by: jilles
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D14142
bectl(8) is an administrative interface for working with ZFS boot
environments, intended to provide a superset of the functionality provided
by sysutils/beadm.
libbe(3) is the back-end library that the required functionality has been
pulled out into for later reuse.
These were originally written for GSoC 2017 under the mentorship of
allanjude@.
bectl(8) has proven pretty stable in my testing, with the known bug
documented in the man page.
Relnotes: yes
- Missing include path
- Fully specify libzfs's dependencies (except for deps pulled in by other
deps) in Makefile.inc1
- Drop WARNS back down to 2 for libbe(3). I do this with much hesitation,
but the libzfs headers are apparently a hot warning-filled mess as far as
GCC 4.2 is concerned.
Taken from:
ommit f604673836
Author: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Sat May 30 09:57:53 2015 -0500
Make arc_prune() asynchronous
As described in the comment above arc_adapt_thread() it is critical
that the arc_adapt_thread() function never sleep while holding a hash
lock. This behavior was possible in the Linux implementation because
the arc_prune() logic was implemented to be synchronous. Under
illumos the analogous dnlc_reduce_cache() function is asynchronous.
To address this the arc_do_user_prune() function is has been reworked
in to two new functions as follows:
* arc_prune_async() is an asynchronous implementation which dispatches
the prune callback to be run by the system taskq. This makes it
suitable to use in the context of the arc_adapt_thread().
* arc_prune() is a synchronous implementation which depends on the
arc_prune_async() implementation but blocks until the outstanding
callbacks complete. This is used in arc_kmem_reap_now() where it
is safe, and expected, that memory will be freed.
This patch additionally adds the zfs_arc_meta_strategy module option
while allows the meta reclaim strategy to be configured. It defaults
to a balanced strategy which has been proved to work well under Linux
but the illumos meta-only strategy can be enabled.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
There used to be one control queue per adapter (the mgmtq) that was
initialized during adapter init and one per port that was initialized
later during port init. This change moves all the control queues (one
per port/channel) to the adapter so that they are initialized during
adapter init and are available before any port is up. This allows the
driver to issue ctrlq work requests over any channel without having to
bring up any port.
MFH: 2 weeks
Sponsored by: Chelsio Communications
In addition import most recent arc_prune_async implementation as dependency
commit 25458cbef9
Author: Tim Chase <tim@chase2k.com>
Date: Wed Jul 13 07:42:40 2016 -0500
Limit the amount of dnode metadata in the ARC
Metadata-intensive workloads can cause the ARC to become permanently
filled with dnode_t objects as they're pinned by the VFS layer.
Subsequent data-intensive workloads may only benefit from about
25% of the potential ARC (arc_c_max - arc_meta_limit).
In order to help track metadata usage more precisely, the other_size
metadata arcstat has replaced with dbuf_size, dnode_size and bonus_size.
The new zfs_arc_dnode_limit tunable, which defaults to 10% of
zfs_arc_meta_limit, defines the minimum number of bytes which is desirable
to be consumed by dnodes. Attempts to evict non-metadata will trigger
async prune tasks if the space used by dnodes exceeds this limit.
The new zfs_arc_dnode_reduce_percent tunable specifies the amount by
which the excess dnode space is attempted to be pruned as a percentage of
the amount by which zfs_arc_dnode_limit is being exceeded. By default,
it tries to unpin 10% of the dnodes.
The problem of dnode metadata pinning was observed with the following
testing procedure (in this example, zfs_arc_max is set to 4GiB):
- Create a large number of small files until arc_meta_used exceeds
arc_meta_limit (3GiB with default tuning) and arc_prune
starts increasing.
- Create a 3GiB file with dd. Observe arc_mata_used. It will still
be around 3GiB.
- Repeatedly read the 3GiB file and observe arc_meta_limit as before.
It will continue to stay around 3GiB.
With this modification, space for the 3GiB file is gradually made
available as subsequent demands on the ARC are made. The previous behavior
can be restored by setting zfs_arc_dnode_limit to the same value as the
zfs_arc_meta_limit.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #4345
Issue #4512
Issue #4773Closes#4858
While STACKSIZE macro is indeed problematic on some systems, the commits
were wrong to shrink il[] and cstk[], because they need to be of the same
size as p_stack[] as they're accessed with the same index ps.tos.
This helps with pkgbase by using CONFS to tag these as config files.
Approved by: allanjude (mentor), ian, cy
Sponsored by: Essen Hackathon
Differential Revision: https://reviews.freebsd.org/D16661
This makes pkgbase easier by tagging these as CONFS so they are properly
tagged as config files.
Approved by: will (mentor)
Sponsored by: Essen Hackathon
Differential Revision: https://reviews.freebsd.org/D16553
The pfi_skip_if() function sometimes caused skipping of groups to work,
if the members of the group used the groupname as a name prefix.
This is often the case, e.g. group lo usually contains lo0, lo1, ...,
but not always.
Rather than relying on the name explicitly check for group memberships.
Obtained from: OpenBSD (pf_if.c,v 1.62, pf_if.c,v 1.63)
Sponsored by: Essen Hackathon
to match reality (slightly different to what was submitted in the
PR: use english word instead of math-symbol).
- Wrap the corresponding part to below 80 characters per line.
Submitted by: yamagi@yamagi.org
PR: 202202
Sponsored by: Essen Hackathon
Fix bug introduced in r98542: previously to this revision the byte-swapped
value was compared at this place. The current check is in a conditional
section where the non-byte-swapped value was already checked to be not
the value which is checked again. As byte-swapping is activated afterwards,
it only makes sense if the byte-swapped value is checked.
Submitted by: Keith White <kwhite@site.uottawa.ca>
PR: 200059
MFC after: 1 month
Sponsored by: Essen Hackathon
This helps with pkgbase as it tags this as a config file so it is handled as
such
Approved by: allanjude (mentor)
Sponsored by: Essen Hackathon
Differential Revision: https://reviews.freebsd.org/D16673
This helps with pkgbase as this config file will now be tagged as a config
file
Approved by: allanjude (mentor)
Sponsored by: Essen Hackathon
Differential Revision: https://reviews.freebsd.org/D16674
This helps with pkgbase to tag this config file as a config file.
Approved by: allanjude (mentor), will (mentor)
Differential Revision: https://reviews.freebsd.org/D16559
This helps pkgbase as this config file will now be tagged as a config file.
Approved by: allanjude (mentor)
Differential Revision: https://reviews.freebsd.org/D16675
This helps with pkgbase as these config files will be properly tagged as
config files.
Approved by: allanjude (mentor), oshogbo
Differential Revision: https://reviews.freebsd.org/D16679
The Makefile part in the PR is solved already differently, so this
part is skipped form the PR The man page change change is slightly
changed to adapt to the way the Makefile works and to the spirit
of what is intended here.
Submitted by: Juan Ramón Molina Menor <info@juanmolina.eu>
PR: 194910
Sponsored by: Essen Hackathon
SVN r337458 erroneously partially reverted r265885.
This is immediately visible when running the Kyua/ATF tests for
usr.bin/printf, which actually test sh's printf builtin.
PR: 229641
[x86] Fix a really subtle miscompile due to a somewhat glaring bug in
EFLAGS copy lowering.
If you have a branch of LLVM, you may want to cherrypick this. It is
extremely unlikely to hit this case empirically, but it will likely
manifest as an "impossible" branch being taken somewhere, and will be
... very hard to debug.
Hitting this requires complex conditions living across complex
control flow combined with some interesting memory (non-stack)
initialized with the results of a comparison. Also, because you have
to arrange for an EFLAGS copy to be in *just* the right place, almost
anything you do to the code will hide the bug. I was unable to reduce
anything remotely resembling a "good" test case from the place where
I hit it, and so instead I have constructed synthetic MIR testing
that directly exercises the bug in question (as well as the good
behavior for completeness).
The issue is that we would mistakenly assume any SETcc with a valid
condition and an initial operand that was a register and a virtual
register at that to be a register *defining* SETcc...
It isn't though....
This would in turn cause us to test some other bizarre register,
typically the base pointer of some memory. Now, testing this register
and using that to branch on doesn't make any sense. It even fails the
machine verifier (if you are running it) due to the wrong register
class. But it will make it through LLVM, assemble, and it *looks*
fine... But wow do you get a very unsual and surprising branch taken
in your actual code.
The fix is to actually check what kind of SETcc instruction we're
dealing with. Because there are a bunch of them, I just test the
may-store bit in the instruction. I've also added an assert for
sanity that ensure we are, in fact, *defining* the register operand.
=D
Noticed by: kib
MFC after: 1 week
Regardless if a verbose scan is required or not, we'd still want to display the
full SSID name by default so use the IEE80211_NWID_LEN constant to set the
value to use instead.
Tested on rene@'s laptop.
Reviewed by: kp
Sponsored by: Essen Hackathon
Differential Revision: https://reviews.freebsd.org/D16566
It's useful for how to mount an iso file via loopback.
Reviewed by: jilles
Approved by: bcr (mentor)
Differential Revision: https://reviews.freebsd.org/D16067
