Commit Graph

479 Commits

Author SHA1 Message Date
Brian Behlendorf 8ac6ffecaf Remove needfree, desfree, lotsfree #defines
This patch reverts 77ab5dd.  This is now possible because upstream has
refactored the ARC in such a way that these values are only used in a
few key places.  Those places have subsequently been updated to use
the Linux equivalent Linux functionality.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#3637
2015-07-30 11:45:24 -07:00
Brian Behlendorf 9dc5ffbec8 Invert minclsyspri and maxclsyspri
On Linux the meaning of a processes priority is inverted with respect
to illumos.  High values on Linux indicate a _low_ priority while high
value on illumos indicate a _high_ priority.

In order to preserve the logical meaning of the minclsyspri and
maxclsyspri macros when they are used by the illumos wrapper functions
their values have been inverted.  This way when changes are merged
from upstream illumos we won't need to remember to invert the macro.
It could also lead to confusion.

Note this change also reverts some of the priorities changes in prior
commit 62aa81a.  The rational is as follows:

spl_kmem_cache    - High priority may result in blocked memory allocs
spl_system_taskq  - May perform I/O for file backed VDEVs
spl_dynamic_taskq - New taskq threads should be spawned promptly

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Issue zfsonlinux/zfs#3607
2015-07-28 13:59:03 -07:00
Brian Behlendorf 62aa81a577 Add defclsyspri macro
Add a new defclsyspri macro which can be used to request the default
Linux scheduler priority.  Neither the minclsyspri or maxclsyspri map
to the default Linux kernel thread priority.  This makes it awkward to
create taskqs which run with the same priority as the rest of the kernel
threads on the system which can lead to performance issues.

All SPL callers which previously used minclsyspri or maxclsyspri have
been changed to use defclsyspri.  The vast majority of callers were
part of the test suite which won't have an external impact.  The few
places where it could impact performance the change was from maxclsyspri
to defclsyspri.  This makes it more likely the process will be scheduled
which may help performance.

To facilitate further performance analysis the spl_taskq_thread_priority
module option has been added.  When disabled (0) all newly created kernel
threads will use the default kernel thread priority.  When enabled (1)
the specified taskq priority will be used.  By default this value is
enabled (1).

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-07-23 13:25:49 -07:00
Turbo Fredriksson 37d7cd94f3 Support parallel build trees (VPATH builds)
Build products from an out of tree build should be written
relative to the build directory.  Sources should be referred
to by their locations in the source directory.

This is accomplished by adding the 'src' and 'obj' variables
for the module Makefile.am, using relative paths to reference
source files, and by setting VPATH when source files are not
co-located with the Makefile.  This enables the following:

  $ mkdir build
  $ cd build
  $ ../configure
  $ make -s

This change also has the advantage of resolving the following
warning which is generated by modern versions of automake.

  Makefile.am:00: warning: source file 'xxx' is in a subdirectory,
  Makefile.am:00: but option 'subdir-objects' is disabled

Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#1082
2015-07-17 12:53:11 -07:00
Brian Behlendorf 77ab5dd33a Add memory compatibility wrappers
The function vmem_qcache_reap() and global variables 'needfree',
'desfree', and 'lotsfree' are all used in the upstream.  While
these variables have no meaning under Linux they're being defined
as 0's to avoid needing to make additional changes to the ARC code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-06-29 09:26:29 -07:00
Brian Behlendorf f7a973d99b Add TASKQ_DYNAMIC feature
Setting the TASKQ_DYNAMIC flag will create a taskq with dynamic
semantics.  Initially only a single worker thread will be created
to service tasks dispatched to the queue.  As additional threads
are needed they will be dynamically spawned up to the max number
specified by 'nthreads'.  When the threads are no longer needed,
because the taskq is empty, they will automatically terminate.

Due to the low cost of creating and destroying threads under Linux
by default new threads and spawned and terminated aggressively.
There are two modules options which can be tuned to adjust this
behavior if needed.

* spl_taskq_thread_sequential - The number of sequential tasks,
without interruption, which needed to be handled by a worker
thread before a new worker thread is spawned.  Default 4.

* spl_taskq_thread_dynamic - Provides the ability to completely
disable the use of dynamic taskqs on the system.  This is provided
for the purposes of debugging and troubleshooting.  Default 1
(enabled).

This behavior is fundamentally consistent with the dynamic taskq
implementation found in both illumos and FreeBSD.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #458
2015-06-24 15:14:18 -07:00
Brian Behlendorf 5acb2307b2 Add IMPLY() and EQUIV() macros
Added for upstream compatibility, they are of the form:

* IMPLY(a, b) - if (a) then (b)
* EQUIV(a, b) - if (a) then (b) *AND* if (b) then (a)

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-06-24 14:44:47 -07:00
Brian Behlendorf 2345368646 Rename cv_wait_interruptible() to cv_wait_sig()
Commit f752b46e added the cv_wait_interruptible() function to allow
condition variables to be woken by signals.  This function and its
timed wait counterpart should have been named cv_wait_sig() to match
the illumos interface which provides the same functionality.

This patch renames the symbol but leaves a #define compatibility
wrapper in place until the ZFS code can be moved to the correct
name.

This patch also makes a small number of cosmetic changes to make
the condvar source and header cstyle clean.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #456
2015-06-10 16:36:12 -07:00
Brian Behlendorf 86c16c59fe Retire rwsem_is_locked() compat
Stock Linux 2.6.32 and earlier kernels contained a broken version of
rwsem_is_locked() which could return an incorrect value.  Because of
this compatibility code was added to detect the broken implementation
and replace it with our own if needed.

The fix for this issue was merged in to the mainline Linux kernel as
of 2.6.33 and the major enterprise distributions based on 2.6.32 have
all backported the fix.  Therefore there is no longer a need to carry
this code and it can be removed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #454
2015-06-10 16:35:48 -07:00
Chris Dunlop a876b0305e Make taskq_wait() block until the queue is empty
Under Illumos taskq_wait() returns when there are no more tasks
in the queue.  This behavior differs from ZoL and FreeBSD where
taskq_wait() returns when all the tasks in the queue at the
beginning of the taskq_wait() call are complete.  New tasks
added whilst taskq_wait() is running will be ignored.

This difference in semantics makes it possible that new subtle
issues could be introduced when porting changes from Illumos.
To avoid that possibility the taskq_wait() function is being
updated such that it blocks until the queue in empty.

The previous behavior remains available through the
taskq_wait_outstanding() interface.  Note that this function
was previously called taskq_wait_all() but has been renamed
to avoid confusion.

Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #455
2015-06-09 12:20:12 -07:00
Brian Behlendorf dc5e8b7041 Add boot_ncpus macro
For compatibility define boot_ncpus as num_online_cpus().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-05-21 09:58:01 -07:00
Richard Yao d3c677bcd3 Implement areleasef()
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #449
2015-04-24 13:02:37 -07:00
Tim Chase ae26dd0039 Don't allow shrinking a PF_FSTRANS context
Avoid deadlocks when entering the shrinker from a PF_FSTRANS context.

This patch also reverts commit d0d5dd7 which added MUTEX_FSTRANS.  Its
use has been deprecated within ZFS as it was an ineffective mechanism
to eliminate deadlocks.  Among other things, it introduced the need for
strict ordering of mutex locking and unlocking in order that the
PF_FSTRANS flag wouldn't set incorrectly.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #446
2015-04-03 11:32:31 -07:00
Chris Dunlop c089961110 Add crgetzoneid() stub
Illumos 3897 introduces a dependency on crgetzoneid(). Stub it out until
such time as zones are implemented.

References:
  https://www.illumos.org/issues/3897
  https://github.com/illumos/illumos-gate/commit/fb7001f

Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #444
2015-04-02 09:49:55 -07:00
Tim Chase 79a0056e13 Add mutex_enter_nested() which maps to mutex_lock_nested()
Also add support for the "name" parameter in mutex_init().  The name
allows for better diagnostics, namely in /proc/lock_stats when
lock debugging is enabled.  Nested mutexes are necessary to support
CONFIG_PROVE_LOCKING. ZoL can use mutex_enter_nested()'s "class" argument
to to convey the locking hierarchy.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #439
2015-03-20 13:53:31 -07:00
Brian Behlendorf d0d5dd7144 Add MUTEX_FSTRANS mutex type
There are regions in the ZFS code where it is desirable to be able
to be set PF_FSTRANS while a specific mutex is held.  The ZFS code
could be updated to set/clear this flag in all the correct places,
but this is undesirable for a few reasons.

1) It would require changes to a significant amount of the ZFS
   code.  This would complicate applying patches from upstream.

2) It would be easy to accidentally miss a critical region in
   the initial patch or to have an future change introduce a
   new one.

Both of these concerns can be addressed by adding a new mutex type
which is responsible for managing PF_FSTRANS, support for which was
added to the SPL in commit 9099312 - Merge branch 'kmem-rework'.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #435
2015-03-03 10:18:24 -08:00
Brian Behlendorf 5f920fbee1 Retire MUTEX_OWNER checks
To minimize the size of a kmutex_t a MUTEX_OWNER check was added.
It allowed the kmutex_t wrapper to leverage the mutex owner which was
already stored in the mutex for certain kernel configurations.

The upside to this was that it reduced the size of the kmutex_t wrapper
structure by the size of a task_struct pointer (4/8 bytes).  The
downside was that two mutex implementations needed to be maintained.
Depending on your exact kernel configuration the correct one would
be selected.

Over the years this solution worked but it could be fragile since it
depending heavily on assumed kernel mutex implementation details.  For
example the SPL_AC_MUTEX_OWNER_TASK_STRUCT configure check needed to
be added when the kernel changed how the owner was stored.  It also
made the code more complicated than it needed to be.

Therefore, in the name of simplicity and portability this optimization
is being retired.  It will slightly increase the memory requirements
for a kmutex_t but only very slightly.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #435
2015-03-03 10:13:33 -08:00
Brian Behlendorf a900e28e71 Fix cstyle issue in mutex.h
This patch only addresses the issues identified by the style checker
in mutex.h.  It contains no functional changes.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Issue #435
2015-03-03 10:13:25 -08:00
Brian Behlendorf c1bc8e610b Retire spl_module_init()/spl_module_fini()
In the original implementation of the SPL wrappers were provided
for module initialization and cleanup.  This was done to abstract
away any compatibility code which might be needed for the SPL.

As it turned out the only significant compatibility issue was that
the default pwd during module load differed under Illumos and Linux.
Since this is such as minor thing and the wrappers complicate the
code they are being retired.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#2985
2015-02-27 13:43:39 -08:00
Brian Behlendorf ee33517452 Use __get_free_pages() for emergency objects
The __get_free_pages() function must be used in place of kmalloc()
to ensure the __GFP_COMP is strictly honored.  This is due to
kmalloc() being layered on the generic Linux slab caches.  It
wasn't until recently that all caches were created using __GFP_COMP.
This means that it is possible for a kmalloc() which passed the
__GFP_COMP flag to be returned a non-compound allocation.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:58:11 -08:00
Brian Behlendorf 3018bffa9b Refine slab cache sizing
This change is designed to improve the memory utilization of
slabs by more carefully setting their size.  The way the code
currently works is problematic for slabs which contain large
objects (>1MB).  This is due to slabs being unconditionally
rounded up to a power of two which may result in unused space
at the end of the slab.

The reason the existing code rounds up every slab is because it
assumes it will backed by the buddy allocator.  Since the buddy
allocator can only performs power of two allocations this is
desirable because it avoids wasting any space.  However, this
logic breaks down if slab is backed by vmalloc() which operates
at a page level granularity.  In this case, the optimal thing to
do is calculate the minimum required slab size given certain
constraints (object size, alignment, objects/slab, etc).

Therefore, this patch reworks the spl_slab_size() function so
that it sizes KMC_KMEM slabs differently than KMC_VMEM slabs.
KMC_KMEM slabs are rounded up to the nearest power of two, and
KMC_VMEM slabs are allowed to be the minimum required size.

This change also reduces the default number of objects per slab.
This reduces how much memory a single cache object can pin, which
can result in significant memory saving for highly fragmented
caches.  But depending on the workload it may result in slabs
being allocated and freed more frequently.  In practice, this
has been shown to be a better default for most workloads.

Also the maximum slab size has been reduced to 4MB on 32-bit
systems.  Due to the limited virtual address space it's critical
the we be as frugal as possible.  A limit of 4M still lets us
reasonably comfortably allocate a limited number of 1MB objects.

Finally, the kmem:slab_small and kmem:slab_large SPLAT tests
were extended to provide better test coverage of various object
sizes and alignments.  Caches are created with random parameters
and their basic functionality is verified by allocating several
slabs worth of objects.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:09 -08:00
Richard Yao c2fa09454e Add hooks for disabling direct reclaim
The port of XFS to Linux introduced a thread-specific PF_FSTRANS bit
that is used to mark contexts which are processing transactions.  When
set, allocations in this context can dip into kernel memory reserves
to avoid deadlocks during writeback.  Linux 3.9 provided the additional
PF_MEMALLOC_NOIO for disabling __GFP_IO in page allocations, which XFS
began using in 3.15.

This patch implements hooks for marking transactions via PF_FSTRANS.
When an allocation is performed in the context of PF_FSTRANS, any
KM_SLEEP allocation is transparently converted to a GFP_NOIO allocation.

Additionally, when using a Linux 3.9 or newer kernel, it will set
PF_MEMALLOC_NOIO to prevent direct reclaim from entering pageout() on
on any KM_PUSHPAGE or KM_NOSLEEP allocation.  This effectively allows
the spl_vmalloc() helper function to be used safely in a thread which
is responsible for IO.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:09 -08:00
Brian Behlendorf c3eabc75b1 Refactor generic memory allocation interfaces
This patch achieves the following goals:

1. It replaces the preprocessor kmem flag to gfp flag mapping with
   proper translation logic. This eliminates the potential for
   surprises that were previously possible where kmem flags were
   mapped to gfp flags.

2. It maps vmem_alloc() allocations to kmem_alloc() for allocations
   sized less than or equal to the newly-added spl_kmem_alloc_max
   parameter.  This ensures that small allocations will not contend
   on a single global lock, large allocations can still be handled,
   and potentially limited virtual address space will not be squandered.
   This behavior is entirely different than under Illumos due to
   different memory management strategies employed by the respective
   kernels.  However, this functionally provides the semantics required.

3. The --disable-debug-kmem, --enable-debug-kmem (default), and
   --enable-debug-kmem-tracking allocators have been unified in to
   a single spl_kmem_alloc_impl() allocation function.  This was
   done to simplify the code and make it more maintainable.

4. Improve portability by exposing an implementation of the memory
   allocations functions that can be safely used in the same way
   they are used on Illumos.   Specifically, callers may safely
   use KM_SLEEP in contexts which perform filesystem IO.  This
   allows us to eliminate an entire class of Linux specific changes
   which were previously required to avoid deadlocking the system.

This change will be largely transparent to existing callers but there
are a few caveats:

1. Because the headers were refactored and extraneous includes removed
   callers may find they need to explicitly add additional #includes.
   In particular, kmem_cache.h must now be explicitly includes to
   access the SPL's kmem cache implementation.  This behavior is
   different from Illumos but it was done to avoid always masking
   the Linux slab functions when kmem.h is included.

2. Callers, like Lustre, which made assumptions about the definitions
   of KM_SLEEP, KM_NOSLEEP, and KM_PUSHPAGE will need to be updated.
   Other callers such as ZFS which did not will not require changes.

3. KM_PUSHPAGE is no longer overloaded to imply GFP_NOIO.  It retains
   its original meaning of allowing allocations to access reserved
   memory.  KM_PUSHPAGE callers can be converted back to KM_SLEEP.

4. The KM_NODEBUG flags has been retired and the default warning
   threshold increased to 32k.

5. The kmem_virt() functions has been removed.  For callers which
   need to distinguish between a physical and virtual address use
   is_vmalloc_addr().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:09 -08:00
Brian Behlendorf b34b95635a Fix kmem cstyle issues
Address all cstyle issues in the kmem, vmem, and kmem_cache source
and headers.  This will done to make it easier to review subsequent
changes which will rework the kmem/vmem implementation.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:09 -08:00
Brian Behlendorf e5b9b344c7 Refactor existing code
This change introduces no functional changes to the memory management
interfaces.  It only restructures the existing codes by separating the
kmem, vmem, and kmem cache implementations in the separate source and
header files.

Splitting this functionality in to separate files required the addition
of spl_vmem_{init,fini}() and spl_kmem_cache_{initi,fini}() functions.

Additionally, several minor changes to the #include's were required to
accommodate the removal of extraneous header from kmem.h.

But again, while large this patch introduces no functional changes.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:08 -08:00
Richard Yao 6ecf6d7228 Revert "Add PF_NOFS debugging flag"
This reverts commit eb0f407a2b in
preperation for updating the kmem/vmem infrastructure to use the
PF_FSTRANS flag.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:08 -08:00
Tim Chase 47af4b76ff Use current_kernel_time() in the time compatibility wrappers
Since the Linux kernel's utimens family of functions uses
current_kernel_time(), we need to do the same in the context of ZFS
or else there can be discrepencies in timestamps (they go backward)
if userland code does:

	fd = creat(FNAME, 0600);
	(void) futimens(fd, NULL);

The getnstimeofday() function generally returns a slightly lower time
value.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#3006
2015-01-16 13:54:35 -08:00
Chunwei Chen a3c1eb7772 mutex: force serialization on mutex_exit() to fix races
It is known that mutexes in Linux are not safe when using them to
synchronize the freeing of object in which the mutex is embedded:

http://lwn.net/Articles/575477/

The known places in ZFS which are suspected to suffer from the race
condition are zio->io_lock and dbuf->db_mtx.

* zio uses zio->io_lock and zio->io_cv to synchronize freeing
  between zio_wait() and zio_done().
* dbuf uses dbuf->db_mtx to protect reference counting.

This patch fixes this kind of race by forcing serialization on
mutex_exit() with a spin lock, making the mutex safe by sacrificing
a bit of performance and memory overhead.

This issue most commonly manifests itself as a deadlock in the zio
pipeline caused by a process spinning on the damaged mutex.  Similar
deadlocks have been reported for the dbuf->db_mtx mutex.  And it can
also cause a NULL dereference or bad paging request under the right
circumstances.

This issue any many like it are linked off the zfsonlinux/zfs#2523
issue.  Specifically this fix resolves at least the following
outstanding issues:

zfsonlinux/zfs#401
zfsonlinux/zfs#2523
zfsonlinux/zfs#2679
zfsonlinux/zfs#2684
zfsonlinux/zfs#2704
zfsonlinux/zfs#2708
zfsonlinux/zfs#2517
zfsonlinux/zfs#2827
zfsonlinux/zfs#2850
zfsonlinux/zfs#2891
zfsonlinux/zfs#2897
zfsonlinux/zfs#2247
zfsonlinux/zfs#2939

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #421
2014-12-19 10:18:47 -08:00
Ned Bass 52479ecf58 Remove compat includes from sys/types.h
Don't include the compatibility code in linux/*_compat.h in the public
header sys/types.h. This causes problems when an external code base
includes the ZFS headers and has its own conflicting compatibility code.
Lustre, in particular, defined SHRINK_STOP for compatibility with
pre-3.12 kernels in a way that conflicted with the SPL's definition.
Because Lustre ZFS OSD includes ZFS headers it fails to build due to a
'"SHRINK_STOP" redefined' compiler warning.  To avoid such conflicts
only include the compat headers from .c files or private headers.

Also, for consistency, include sys/*.h before linux/*.h then sort by
header name.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #411
2014-11-19 10:35:12 -08:00
Brian Behlendorf 8d9a23e82c Retire legacy debugging infrastructure
When the SPL was originally written Linux tracepoints were still
in their infancy.  Therefore, an entire debugging subsystem was
added to facilite tracing which served us well for many years.

Now that Linux tracepoints have matured they provide all the
functionality of the previous tracing subsystem.  Rather than
maintain parallel functionality it makes sense to fully adopt
tracepoints.  Therefore, this patch retires the legacy debugging
infrastructure.

See zfsonlinux/zfs@bc9f413 for the tracepoint changes.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #408
2014-11-19 10:35:07 -08:00
Brian Behlendorf 917fef2732 Lower minimum objects/slab threshold
As long as we can fit a minimum of one object/slab there's no reason
to prevent the creation of the cache.  This effectively pushes the
maximum object size up to 32MB.  The splat cache tests were extended
accordingly to verify this functionality.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-11-05 10:08:21 -08:00
Richard Yao fd05dde75d Kernel header installation should respect --prefix
This is the upstream component of work that enables preliminary support
for building Gentoo's ZFS packaging on other Linux systems via Gentoo
Prefix.

Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #384
2014-10-28 09:31:48 -07:00
Tim Chase 802a4a2ad5 Linux 3.12 compat: shrinker semantics
The new shrinker API as of Linux 3.12 modifies "struct shrinker" by
replacing the @shrink callback with the pair of @count_objects and
@scan_objects.  It also requires the return value of @count_objects to
return the number of objects actually freed whereas the previous @shrink
callback returned the number of remaining freeable objects.

This patch adds support for the new @scan_objects return value semantics
and updates the splat shrinker test case appropriately.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #403
2014-10-28 09:20:13 -07:00
Brian Behlendorf dcf91382b9 Remove vfs_fsync() wrapper
The vfs_fsync() function has been available since Linux 2.6.29.
There is no longer a need to maintain this compatibility code.
However, the HAVE_2ARGS_VFS_FSYNC check was left in place
since that change occured after 2.6.32.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:52 -07:00
Brian Behlendorf 0fac9c9e6d Remove proc_handler() wrapper
As of Linux 2.6.32 the proc handlers where updated to expect only
five arguments.  Therefore there is no longer a need to maintain
this compatibility code and this infrastructure can be simplified.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:52 -07:00
Brian Behlendorf 68a829b29d Remove credential configure checks.
The groups_search() function was never exported by a mainline kernel
therefore we drop this compatibility code and always provide our own
implementation.

Additionally, the cred_t structure has been available since 2.6.29
so there is no longer a need to maintain compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 44778f4110 Remove kallsyms_lookup_name() wrapper
After the removable of get_vmalloc_info(), the unused global memory
variables, and the optional dcache/icache shrinkers there is no
longer a need for the kallsyms compatibility code.  This allows
us to eliminate another brittle area of the code by removing the
kernel upcall this functionality depended on for older kernels.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 89a461e70c Remove shrink_{i,d}node_cache() wrappers
This is optional functionality which may or may not be useful to
ZFS when using older kernels.  It is never a hard requirement.
Therefore this functionality is being removed from the SPL and
a simpler slimmed down version will be added to ZFS.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 8bbbe46f86 Remove global memory variables
Platforms such as Illumos and FreeBSD have historically provided
global variables which summerize the memory state of a system.
Linux on the otherhand doesn't expose any of this information
to kernel modules and uses entirely different mechanisms for
memory management.

In order to simplify the original ZFS port to Linux these global
variables were emulated by the SPL for the benefit of ZFS.  As ZoL
has matured over the years it has moved steadily away from these
interfaces and now no longer depends on them at all.

Therefore, this patch completely removes the global variables
availrmem, minfree, desfree, lotsfree, needfree, swapfs_minfree,
and swapfs_reserve.  This greatly simplifies the memory management
code and eliminates a common area of confusion.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf e1310afae3 Remove get_vmalloc_info() wrapper
The get_vmalloc_info() function was used to back the vmem_size()
function.  This was always problematic and resulted in brittle
code because the kernel never provided a clean interface for
modules.

However, it turns out that the only caller of this function in
ZFS uses it to determine the total virtual address space size.
This can be determined easily without get_vmalloc_info() so
vmem_size() has been updated to take this approach which allows
us to shed the get_vmalloc_info() dependency.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 50e41ab1e1 Remove on_each_cpu() wrapper
The on_each_cpu() function has been available since Linux 2.6.27.
There is no longer a need to maintain this compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf b652d169b0 Remove mutex_lock_nested() wrapper
The mutex_lock_nested() function has been available since Linux 2.6.18.
There is no longer a need to maintain this compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 2bc5666f53 Remove i_mutex() configure check
The inode structure has used i_mutex as its internal locking
primitive since 2.6.16.  The compatibility code to check for
the previous semaphore primitive has been removed.  However,
the wrapper function itself is being kept because it's entirely
possible this primitive will change again to allow finer grained
locking.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf 9f36cace41 Remove kmalloc_node() compatibility code
The kmalloc_node() function has been available since Linux 2.6.12.
There is no longer a need to maintain this compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf d227e114ed Remove linux/uaccess.h header check
The uaccess header has been available in the same location since
Linux 2.6.18.  There is no longer a need to maintain this
compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:51 -07:00
Brian Behlendorf e5b65e3179 Remove uintptr_t typedef
The uintptr_t typedef has been available since Linux 2.6.24.
There is no longer a need to maintain this compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:50 -07:00
Brian Behlendorf ff0582cb39 Remove atomic64_xchg() wrappers
The atomic64_xchg() and atomic64_cmpxchg() functions have been
available since Linux 2.6.24.  There is no longer a need to
maintain this compatibility code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:50 -07:00
Brian Behlendorf 82f2f1a3af Simplify the time compatibility wrappers
Many of the time functions had grown overly complex in order to
handle kernel compatibility issues.  However, as of Linux 2.6.26
all the required functionality is available.  This allows us to
retire numerous configure checks and greatly simplify the time
compatibility wrappers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:50 -07:00
Brian Behlendorf 87f8055a91 Map highbit64() to fls64()
The fls64() function has been available since Linux 2.6.16 and
it should be used to implemented highbit64().  This allows us
to provide an optimized implementation and simplify the code.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:50 -07:00
Brian Behlendorf 9c91800d19 Remove CTL_UNNUMBERED sysctl interface
Support for the CTL_UNNUMBERED sysctl interface was removed in
Linux 2.6.19.  There is no longer any reason to maintain this
compatibility code.  There also issue any reason to keep around
the CTL_NAME macro and helpers so they have been retired.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:50 -07:00