Added highbit64() and howmany() which are used in recent upstream
code. Both highbit() and highbit64() should at some point be
re-factored to use the optimized fls() and fls64() functions.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#363
There have been issues in the past where excessive debug logging
to the console has resulted in significant performance impacts.
In the vast majority of these cases only a few stack traces are
required to diagnose the issue. Therefore, stack traces dumped to
the console will now we limited to 5 every 60s.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Closes#374
As part of the write throttle & i/o schedule performance work the
zfs_trunc() function should have been updated to use TXG_WAIT.
Using TXG_WAIT ensures that the tx will be part of the next txg.
If TXG_NOWAIT is used and retried for ERESTART errors then the
tx can suffer from starvation.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#2488
4756 metaslab_group_preload() could deadlock
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: Saso Kiselkov <saso.kiselkov@nexenta.com>
Approved by: Garrett D'Amore <garrett@damore.org>
The metaslab_group_preload() function grabs the mg_lock and then later
tries to grab the metaslab lock. This lock ordering may lead to a
deadlock since other consumers of the mg_lock will grab the metaslab
lock first.
References:
https://www.illumos.org/issues/4756https://github.com/illumos/illumos-gate/commit/30beaff
Ported-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2488
4730 metaslab group taskq should be destroyed in metaslab_group_destroy()
Reviewed by: Alex Reece <alex.reece@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed by: Rich Lowe <richlowe@richlowe.net>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Dan McDonald <danmcd@omniti.com>
References:
https://www.illumos.org/issues/4730https://github.com/illumos/illumos-gate/commit/be08211
Porting notes:
Under ZFSonlinux, one of the effects of not destroying the taskq is that
zdb would never exit (due to the SPL taskq implementation).
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2488
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
4105 removing a mirrored log device results in a leaked object
4106 asynchronously load metaslab
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Sebastien Roy <seb@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
Prior to this patch, space_maps were preferred solely based on the
amount of free space left in each. Unfortunately, this heuristic didn't
contain any information about the make-up of that free space, which
meant we could keep preferring and loading a highly fragmented space map
that wouldn't actually have enough contiguous space to satisfy the
allocation; then unloading that space_map and repeating the process.
This change modifies the space_map's to store additional information
about the contiguous space in the space_map, so that we can use this
information to make a better decision about which space_map to load.
This requires reallocating all space_map objects to increase their
bonus buffer size sizes enough to fit the new metadata.
The above feature can be enabled via a new feature flag introduced by
this change: com.delphix:spacemap_histogram
In addition to the above, this patch allows the space_map block size to
be increase. Currently the block size is set to be 4K in size, which has
certain implications including the following:
* 4K sector devices will not see any compression benefit
* large space_maps require more metadata on-disk
* large space_maps require more time to load (typically random reads)
Now the space_map block size can adjust as needed up to the maximum size
set via the space_map_max_blksz variable.
A bug was fixed which resulted in potentially leaking an object when
removing a mirrored log device. The previous logic for vdev_remove() did
not deal with removing top-level vdevs that are interior vdevs (i.e.
mirror) correctly. The problem would occur when removing a mirrored log
device, and result in the DTL space map object being leaked; because
top-level vdevs don't have DTL space map objects associated with them.
References:
https://www.illumos.org/issues/4101https://www.illumos.org/issues/4102https://www.illumos.org/issues/4103https://www.illumos.org/issues/4105https://www.illumos.org/issues/4106https://github.com/illumos/illumos-gate/commit/0713e23
Porting notes:
A handful of kmem_alloc() calls were converted to kmem_zalloc(). Also,
the KM_PUSHPAGE and TQ_PUSHPAGE flags were used as necessary.
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2488
This changes moves the called to metaslab_group_alloc_update() to the
metaslab_sync_reassess() function. The original placement of the call
within metaslab_sync_done() appears to have been a simple mistake,
introduced by ac72fac3ea.
This aligns us more closely to the upstream illumos code base.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Update the current code to ensure inodes are never dirtied if they are
part of a read-only file system or snapshot. If they do somehow get
dirtied an attempt will make made to write them to disk. In the case
of snapshots, which don't have a ZIL, this will result in a NULL
dereference in zil_commit().
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2405
When given a pool name via -e, zdb would attempt an import. If it
failed, then it would attempt a verbatim import. This behavior is
not always desirable so a -V switch is added to zdb to control the
behavior. When specified, a verbatim import is done. Otherwise,
the behavior is as it was previously, except no verbatim import
is done on failure.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2372
4168 ztest assertion failure in dbuf_undirty
4169 verbatim import causes zdb to segfault
4170 zhack leaves pool in ACTIVE state
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@nexenta.com>
References:
https://www.illumos.org/issues/4168https://www.illumos.org/issues/4169https://www.illumos.org/issues/4170https://github.com/illumos/illumos-gate/commit/7fdd916
Porting notes:
Of particular interest when troubleshooting corrupted pools, the
commonly-used "zdb -e" operation may perform verbatim imports and
furthermore, it will soon have direct support for verbatim imports via
a new "-V" option. The 4169 fix eliminates a common segfault case in
which spa_history_log_version() tries to access an un-opened dsl_pool_t.
Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2451Closes#2283Closes#2467
The parameter was added as illumos issue 4081 which was committed to
zfsonlinux in ac72fac3ea. This patch
documents the parameter and allows for it to be set as a module parameter.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2483
This patch is a zdb extension of the '-b' option, producing a histogram
of the physical compressed block sizes per DMU object type on disk. The
'-bbbb' option to zdb will uncover this new feature; here's an example
usage on a new pool and snippet of the output it generates:
# zpool create tank /dev/vd{b,c,d}
# dd bs=1k if=/dev/urandom of=/tank/1kfile count=1
# dd bs=3k if=/dev/urandom of=/tank/3kfile count=1
# dd bs=64k if=/dev/urandom of=/tank/64kfile count=1
# zdb -bbbb tank
...
3 68.0K 68.0K 68.0K 22.7K 1.00 34.26 ZFS plain file
psize (in 512-byte sectors): number of blocks
2: 1 *
3: 0
4: 0
5: 0
6: 1 *
7: 0
...
127: 0
128: 1 *
...
The blocks are also broken down by their indirection level. Expanding on
the above example:
# zfs set recordsize=1k tank
# dd bs=1k if=/dev/urandom of=/tank/2x1kfile count=2
# zdb -bbbb tank
...
1 16K 1K 2K 2K 16.00 1.02 L1 ZFS plain file
psize (in 512-byte sectors): number of blocks
2: 1 *
5 70.0K 70.0K 70.0K 14.0K 1.00 35.71 L0 ZFS plain file
psize (in 512-byte sectors): number of blocks
2: 3 ***
3: 0
4: 0
5: 0
6: 1 *
7: 0
...
127: 0
128: 1 *
6 86.0K 71.0K 72.0K 12.0K 1.21 36.73 ZFS plain file
psize (in 512-byte sectors): number of blocks
2: 4 ****
3: 0
4: 0
5: 0
6: 1 *
7: 0
...
127: 0
128: 1 *
...
There's now a single 1K L1 block which is the indirect block needed for
the '2x1kfile' file just created, as well as two more 1K L0 blocks from
the same file.
This can be used to get a distribution of the block sizes used within
the pool, on a per object type basis.
References:
https://illumos.org/issues/3641https://github.com/illumos/illumos-gate/commit/490d05b
Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Boris Protopopov <boris.protopopov@me.com>
Closes#2456
If the smaller of 2 different sized child vdev's of a mirrored vdev is
detached, and the pool has the autoexpand property set to off, as the
remaining larger vdev is promoted to a top level vdev it fails to retain
the asize of the original top level mirror vdev and therefore partially
autoexpands.
This partially autoexpanded state leaves the new vdev too large to
re-mirror by adding the smaller vdev back in, and the pool fails to
utilize the space until next imported.
If the autoexpand property is set to on, the child vdev grows
in size after it has been promoted to a top level vdev as expected.
This commit causes the remaining child mirror to retain the asize of its
old parent mirror vdev if the autoexpand property is set to off,
this allows the smaller vdev to be re-added if required the vdev
can then be told to expand if required by the usual using zpool online -e.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrew Barnes <barnes333@gmail.com>
Signed-off-by: George Wilson <george.wilson@delphix.com>
Closes#1208
Spl's debugging and assertion macros macro used the typical do/while(0)
form for if/else friendliness, however, this limits their use in contexts
where a do loop is not valid; such as within another multi-statement
style macro.
The following macros have been converted to not use do/while(0):
PANIC, ASSERT, ASSERTF, VERIFY, VERIFY3_IMPL
PANIC has been converted to a wrapper around the new spl_PANIC() function.
The other macros have been converted to use the "&&" operator for the
branch-predicition conditional and also to use spl_PANIC().
The __ASSERT() macro was not touched. It is only used by the debugging
infrastructure and that code, including this macro, will be retired when
the tracepoint patches are merged.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#367
Most ZFS implementations seemed to have missed this bit of documentation.
The additional text is based on FreeBSD's man page.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2416
Updates 962d524212.
The referenced fix to get_numeric_property() caused numeric property
lookups to consider the type of the parent (head) dataset when checking
validity but there are some cases in the caller expects to see the
property's default value even when the lookup is invalid.
One case in which this is true is change_one() which is part of the
renaming infrastructure. It may look up "zoned" on a snapshot of a volume
which is not valid but it expects to see the default value of false.
There may be other, yet unidentified cases in which zfs_prop_get_int()
is used on technically invalid properties but which expect the property's
default value to be returned.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Turbo Fredriksson <turbo@bayour.com>
Closes#2320
4936 lz4 could theoretically overflow a pointer with a certain input
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Keith Wesolowski <keith.wesolowski@joyent.com>
Approved by: Gordon Ross <gordon.ross@nexenta.com>
Ported by: Tim Chase <tim@chase2k.com>
References:
https://illumos.org/issues/4936https://github.com/illumos/illumos-gate/commit/58d0718
Porting notes:
This fixes the widely-reported "20-year-old vulnerability" in
LZO/LZ4 implementations which inherited said bug from the reference
implementation.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2429
Added several comments regarding the removal of real_LZ4_uncompress()
which exists in the reference implementation but has been removed here
since it's not used.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When adding or replacing a vdev with a different sector size the
error message should be more useful. In addition to describing
the problem provide a hint that the '-o ashift' option can be
used to override the optimal default value.
Since using a non-optimal value may incur a significant performance
penalty we should issue this error. But there a numerous reasons
why a administrator may wish to do this anyway.
Signed-off-by: Niklas Edmundsson <ZNikke@github>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2421
Users need to be aware that when replacing devices in an existing
pool they may need to override automatically detected ashift value.
This will all depend on the exact hardware they are using.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2024
The property name gets mangled with the explanation due to the property
length. Fixed by putting the explanation on the next line.
Before:
unsupported@feature_Info rmation about unsupported features that are
enabled on the pool. See zpool-features(5) for details.
After:
unsupported@feature_guid
Information about unsupported features that are enabled on the pool. See
zpool-features(5) for details.
Signed-off-by: SenH <sen@senhaerens.be>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2419
Commit 2ee4e7da accidentally introduced two issues which only occur
when rebuilding the ZFS source rpm outside the ZFS build system.
1) The _dracutdir, _udevdir, and _udevruledir macros must be checked
using the 'undefined' keyword. This was just overlooked in the
patch review and does not cause a failure when using 'make pkg'
because the values are provided by the make target.
2) The default _udevruledir path included a typo.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2310
There are two common locations where udev and dracut components are
commonly installed. When building packages using the 'make rpm|deb'
targets check those common locations and pass them to rpmbuild. For
non-standard configurations these values can be provided by the
the following configure options:
--with-udevdir=DIR install udev helpers [default=check]
--with-udevruledir=DIR install udev rules [[UDEVDIR/rules.d]]
--with-dracutdir=DIR install dracut helpers [default=check]
When rebuilding using the source packages the per-distribution
default values specified in the spec file will be used. This is
the preferred way to build packages for a distribution but the
ability to override the defaults is provided as a convenience.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2310Closes#1680
This reverts commit 91579709fc which
limited the asynchronous dispatch to kernel space. We want to do
this for two reasons:
1) While we have slightly more headroom in user space excessively
deep stacks have been observed while running ztest, see #2293.
2) Removing this conditional makes the pipeline behave consistently
regardless of if it's executing in kernel space or user space.
This way we're more likely to uncover subtle issues with ztest.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2384
Set LANG=C before calling 'rpmbuild' to avoid rpmbuild failing on
the translated date string in the changelog.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: zfsonlinux/spl#306
Set LANG=C before calling 'rpmbuild' to avoid rpmbuild failing on
the translated date string in the changelog.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#306
These options have existed for a long time but have historically
been undocumented because they are not guaranteed to be safe. They
should only be used as a last resort when attempting to recover a
damaged pool.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1130
Document that the scan-related parameters are, in fact, applicable only
to scrub and/or resilver operations as appropriate.
Expand a few of the prefetch-related descriptions.
Add clarification to other module parameters.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2361
* Remove the references to share(1M), unshare(1M) and dfstab(4)
since they are not applicable to Linux.
* Add the exact exportfs command line used when setting sharenfs=on.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue: #1641
Users need to be aware that when adding devices to an existing pool
they may need to override automatically detected ashift value.
This will all depend on the exact hardware they are using.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #2024
According to the man page, "When the noauto option is set, a dataset
can only be mounted and unmounted explicitly. The dataset is not
mounted automatically when the dataset is created or imported ...."
When cloning a dataset the canmount property was not being honored.
This patch adds the required check to achieve the behavior described
in the man page.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2241
This adds ability to set the location of the kernel via defines
when building from the spec files. This is useful when building
against a kernel installed in a non-standard location.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1874
From day one the various ZFS libraries should have been placed in their
own sub-packages. Primarily this allows for multiple major versions of
the libraries to be concurrently installed. It also facilitates a
smaller build environment by minimizing the required dependencies.
The specific changes required to split the libraries from the utilities
are as follows:
* libzpool2, libnvpair1, libuutil1, and libzfs2 packages were added
and contain the versioned shared libraries. The Fedora packaging
guidelines discourage providing static libraries so they are not
included in the packages.
http://fedoraproject.org/wiki/Packaging:Guidelines#Packaging_Static_Libraries
* The zfs-devel package was renamed libzfs2-devel and the new package
obsoletes the old zfs-devel package. This package includes all
the required headers for the libzpool2, libnvpair1, libuutil1, and
libzfs2 libraries and their respective unversioned shared libraries.
This package should eventually be split in to individual lib*-devel
packages but it will still take some work to cleanly separate them.
Therefore the libzfs2-devel package provides the expected lib*-devel
packages so the all proper dependencies can still be created.
http://fedoraproject.org/wiki/Packaging:Guidelines#Devel_Packages
* Moved '/sbin/ldconfig' execution from the zfs packge to each of the
new library packages as described by the packaging guidelines.
http://fedoraproject.org/wiki/Packaging:Guidelines#Shared_Libraries
* The /usr/share/doc/ files were moved in to the libzfs2-devel package.
* Updated config/deb.am to be aware of the packaging changes. This
ensures that 'deb-utils' make target converts all the resulting
packages generated by the 'rpm-utils' target.
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes: #2329Closes: #2341
Issue: #2145
Clang's static analyzer reported that the value assigned to pcksum is
never used. That is because we initialize both zc and pcksum to {{ 0 }}
and then do `pcksum = zc;`. That is fairly pointless. However, it has
the effect of generating a false positive in Clang's static analyzer.
Since noise from false positives can obscure real issues, we fix it
anyway.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2330
Clang's static analyzer reported a memory leak in zpool_clear_label().
Upon review, it turns out to be right. This should be a very short lived
leak because no daemons use this functionality, but that does not
preclude the possibility of third party daemons that do use it. Lets fix
it to be a good Samaritan.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2330
Some kernel definitions were buried inside the #if... #endif logic for
ACLs. When ACLs are not available these definitions get lost causing
the build to fail.
Signed-off-by: Chris Wedgwood <cw@f00f.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2349
Running 'yum upgrade zfs-dkms' package could appear to work properly
and still leave you with no zfs modules installed. This will occur
when only the zfs release, and not the version, are incremented.
This may be the case for a fast moving zfs-testing repository.
During the upgrade process DKMS will realize that zfs-x.y.z is already
installed and remove it. DKMS then correctly builds the new modules
for zfs-x.y.z. However, as a final step when the old zfs-x.y.z-r is
removed the %preun script runs and removes the newly build modules.
To handle this case the %preun script has been updated to only run
when the installed version exactly matches the full spec file version.
This change also updated ChangeLog section based on the DKMS
reference spec file.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Running 'yum upgrade spl-dkms' package could appear to work properly
and still leave you with no spl modules installed. This will occur
when only the spl release, and not the version, are incremented.
This may be the case for a fast moving spl-testing repository.
During the upgrade process DKMS will realize that spl-x.y.z is already
installed and remove it. DKMS then correctly builds the new modules
for spl-x.y.z. However, as a final step when the old spl-x.y.z-r is
removed the %preun script runs and removes the newly build modules.
To handle this case the %preun script has been updated to only run
when the installed version exactly matches the full spec file version.
This change also updated ChangeLog section based on the DKMS
reference spec file.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When creating packages in a git repository the release number
can be automatically set by 'git describe'. This normally works
well but if your repository has newer tags which match the form
NAME-VERSION* the release may be incorrectly calculated. To
prevent this the match patten has been restricted to the contents
of the META file, NAME-VERSION.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When creating packages in a git repository the release number
can be automatically set by 'git describe'. This normally works
well but if your repository has newer tags which match the form
NAME-VERSION* the release may be incorrectly calculated. To
prevent this the match patten has been restricted to NAME-VERSION.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
We should not override the default memory type of the kmem cache. This
was done previously to force certain objects which were slightly over
object size limit cut off in to KMC_KMEM caches for better performance.
The zfsonlinux/spl#356 patch slightly increases the default cut off
from 511 bytes 1024 bytes for x86_64. This means there is long longer
a need to override the default for the caches. And since the default
values are now being used the new spl_kmem_cache_slab_limit and
spl_kmem_cache_kmem_limit tunables will apply to all kmem caches.
The following is a list of caches that will be impacted:
| object size | forced type | default type
----------------- | ------------- | ------------- | --------------
dnode_t | 936 bytes | KMC_KMEM | KMC_KMEM
zio_cache | 1104 bytes | *KMC_KMEM | *KMC_VMEM
zio_link_cache | 48 bytes | KMC_KMEM | KMC_KMEM
zio_vdev_cache | 131088 bytes | KMC_VMEM | KMC_VMEM
zio_buf_512 | 512 bytes | KMC_KMEM | KMC_KMEM
zio_data_buf_512 | 512 bytes | KMC_KMEM | KMC_KMEM
zio_buf_1024 | 1024 bytes | KMC_KMEM | KMC_KMEM
zio_data_buf_1024 | 1024 bytes | +KMC_VMEM | +KMC_KMEM
* Cache memory type will change from KMC_KMEM to KMC_VMEM.
+ Cache memory type will change from KMC_VMEM to KMC_KMEM.
This patch removes another slight point of divergence between ZoL
and Illumos.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Closes#2337
The correct behavior for all registered shrinkers is to return the
number of objects in their cache. In theory this allows the Linux
VM to balance memory reclaim across all registered caches.
In commit b9b3715 this behavior was disabled in favor of returning
-1 which notifies the VM that no additional objects are available
for reclaim. This was done as a workaround to resolve thrashing
in shrink_slabs() which could occur when memory was low and numerous
core where in reclaim. Unfortunately, this has been observed to
increase the likelihood of OOM events when SPL slab consumers are
responsible for consuming the majority of memory.
Therefore, this patch makes this behavior tunable. Setting the
spl_kmem_cache_reclaim module option to 0x1 will result in the
shrinker only being called once. This is the default behavior.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Closes#358
For small objects the Linux slab allocator has several advantages
over its counterpart in the SPL. These include:
1) It is more memory-efficient and packs objects more tightly.
2) It is continually tuned to maximize performance.
Therefore it makes sense to layer the SPLs slab allocator on top
of the Linux slab allocator. This allows us to leverage the
advantages above while preserving the Illumos semantics we depend
on. However, there are some things we need to be careful of:
1) The Linux slab allocator was never designed to work well with
large objects. Because the SPL slab must still handle this use
case a cut off limit was added to transition from Linux slab
backed objects to kmem or vmem backed slabs.
spl_kmem_cache_slab_limit - Objects less than or equal to this
size in bytes will be backed by the Linux slab. By default
this value is zero which disables the Linux slab functionality.
Reasonable values for this cut off limit are in the range of
4096-16386 bytes.
spl_kmem_cache_kmem_limit - Objects less than or equal to this
size in bytes will be backed by a kmem slab. Objects over this
size will be vmem backed instead. This value defaults to
1/8 a page, or 512 bytes on an x86_64 architecture.
2) Be aware that using the Linux slab may inadvertently introduce
new deadlocks. Care has been taken previously to ensure that
all allocations which occur in the write path use GFP_NOIO.
However, there may be internal allocations performed in the
Linux slab which do not honor these flags. If this is the case
a deadlock may occur.
The path forward is definitely to start relying on the Linux slab.
But for that to happen we need to start building confidence that
there aren't any unexpected surprises lurking for us. And ideally
need to move completely away from using the SPLs slab for large
memory allocations. This patch is a first step.
NOTES:
1) The KMC_NOMAGAZINE flag was leveraged to support the Linux slab
backed caches but it is not supported for kmem/vmem backed caches.
2) Regardless of the spl_kmem_cache_*_limit settings a cache may
be explicitly set to a given type by passed the KMC_KMEM,
KMC_VMEM, or KMC_SLAB flags during cache creation.
3) The constructors, destructors, and reclaim callbacks are all
functional and will be called regardless of the cache type.
4) KMC_SLAB caches will not appear in /proc/spl/kmem/slab due to
the issues involved in presenting correct object accounting.
Instead they will appear in /proc/slabinfo under the same names.
5) Several kmem SPLAT tests needed to be fixed because they relied
incorrectly on internal kmem slab accounting. With the updated
test cases all the SPLAT tests pass as expected.
6) An autoconf test was added to ensure that the __GFP_COMP flag
was correctly added to the default flags used when allocating
a slab. This is required to ensure all pages in higher order
slabs are properly refcounted, see ae16ed9.
7) When using the SLUB allocator there is no need to attempt to
set the __GFP_COMP flag. This has been the default behavior
for the SLUB since Linux 2.6.25.
8) When using the SLUB it may be desirable to set the slub_nomerge
kernel parameter to prevent caches from being merged.
Original-patch-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: DHE <git@dehacked.net>
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Closes#356
Resolve gcc 4.9.0 20140507 warnings about uninitialized 'ptr' when
using -Wmaybe-uninitialized. The first two cases appears appear
to be legitimate but not the second two. In general this is a
good practice so they are all initialized.
Signed-off-by: Marcel Huber <marcelhuberfoo@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2345
