Commit Graph

64 Commits

Author SHA1 Message Date
Brian Behlendorf 5461eefe50
Fix cstyle warnings
This patch contains no functional changes.  It is solely intended
to resolve cstyle warnings in order to facilitate moving the spl
source code in to the zfs repository.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #681
2018-02-07 11:49:38 -08:00
Olaf Faaland 4b393c50ae Make file headers conform to ZFS style standard
No semantic changes.

Change
 /************\
and
 \************/

to

 /*
and
  */

Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
2017-10-09 14:27:27 -07:00
Chunwei Chen 6ecfd2b553 Add __divmoddi4 and __udivmoddi4 for 32-bit arch
gcc-7 seems to use __udivmoddi4 for 64-bit division on 32-bit arch. This
patch implement them so we don't get undefined reference error.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes zfsonlinux/zfs#6417 
Closes #636
2017-08-03 10:41:42 -07:00
Brian Behlendorf c93d9dff36 Don't cache the system hostid
Historically the SPL cached the system hostid the first time it
was accessed.  This was done to speed up subsequent accesses.
But in practice the system host id is rarely accessed and its
inconvenient that it doesn't promptly detect /etc/hostid
configuration changes.  Therefore, zone_get_hostid() has been
updated to always refresh the system hostid reported.

Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #626
2017-07-13 13:22:28 -04:00
Olaf Faaland bf8abea4da Linux 4.11 compat: remove stub for __put_task_struct
Before kernel 2.6.29 credentials were embedded in task_structs, and zfs had
cases where one thread would need to refer to the credential of another thread,
forcing it to take a hold on the foreign thread's task_struct to ensure it was
not freed.

Since 2.6.29, the credential has been moved out of the task_struct into a
cred_t.

In addition, the mainline kernel originally did not export __put_task_struct()
but the RHEL5 kernel did, according to zfsonlinux/spl@e811949a57.  As of
2.6.39 the mainline kernel exports it.

There is no longer zfs code that takes or releases holds on a task_struct, and
so there is no longer any reference to __put_task_struct().

This affects the linux 4.11 kernel because the prototype for
__put_task_struct() is in a new include file (linux/sched/task.h) and so the
config check failed to detect the exported symbol.

Removing the unnecessary stub and corresponding config check.  This works on
kernels since the oldest one currently supported, 2.6.32 as shipped with
Centos/RHEL.

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #608
2017-03-20 17:43:45 -07:00
tuxoko 0d26756665 Fix out-of-bound in per_cpu in spl_random_init
When iterating per_cpu values, we need to use for_each_possible_cpu. While
NR_CPUS indicates the number of CPU supported by the kernel, it might not
initialize all of them if the kernel decides it's not possible to use them.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #578
2016-10-07 20:59:46 -07:00
Brian Behlendorf 341dfdb3fd Fix p0 initializer
Due to changes in the task_struct the following warning is occurs
when initializing the global p0.  Since this structure only exists
for it's address to be taken initialize it in a manor which isn't
sensitive to internal changes to the structure.

  module/spl/spl-generic.c:58:1: error: missing braces around
  initializer [-Werror=missing-braces]

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #576
2016-10-04 17:26:36 -07:00
Richard Yao 0b43696e66 random_get_pseudo_bytes() need not provide cryptographic strength entropy
Perf profiling of dd on a zvol revealed that my system spent 3.16% of
its time in random_get_pseudo_bytes(). No SPL consumers need
cryptographic strength entropy, so we can reduce our overhead by
changing the implementation to utilize a fast PRNG.

The Linux kernel did not export a suitable PRNG function until it
exported get_random_int() in Linux 3.10. While we could implement an
autotools check so that we use it when it is available or even try to
access the symbol on older kernels where it is not exported using the
fact that it is exported on newer ones as justification, we can instead
implement our own pseudo-random data generator. For this purpose, I have
written one based on a 128-bit pseudo-random number generator proposed
in a paper by Sebastiano Vigna that itself was based on work by the late
George Marsaglia.

http://vigna.di.unimi.it/ftp/papers/xorshiftplus.pdf

Profiling the same benchmark with an earlier variant of this patch that
used a slightly different generator (roughly same number of
instructions) by the same author showed that time spent in
random_get_pseudo_bytes() dropped to 0.06%. That is a factor of 50
improvement. This particular generator algorithm is also well known to
be fast:

http://xorshift.di.unimi.it/#speed

The benchmark numbers there state that it runs at 1.12ns/64-bits or 7.14
GBps of throughput on an Intel Core i7-4770 in what is presumably a
single-threaded context. Using it in `random_get_pseudo_bytes()` in the
manner I have will probably not reach that level of performance, but it
should be fairly high and many times higher than the Linux
`get_random_bytes()` function that we use now, which runs at 16.3 MB/s
on my Intel Xeon E3-1276v3 processor when measured by using dd on
/dev/urandom.

Also, putting this generator's seed into per-CPU variables allows us to
eliminate overhead from both spin locks and CPU memory barriers, which
is NUMA friendly.

We could have alternatively modified consumers to use something like
`gethrtime() % 3` as suggested by both Matthew Ahrens and Tim Chase, but
that has a few potential problems that this approach avoids:

1. Switching to `gethrtime() % 3` in hot code paths today requires
diverging from illumos-gate and does nothing about potential future
patches from illumos-gate that call our slow `random_get_pseudo_bytes()`
in different hot code paths. Reimplementing `random_get_pseudo_bytes()`
with a per-CPU PRNG avoids both of those things entirely, which means
less work for us in the future.

2.  Looking at the code that implements `gethrtime()`, I think it is
unlikely to be faster than this per-CPU PRNG implementation of
`random_get_pseudo_bytes()`. It would be best to go with something fast
now so that there is no point in revisiting this from a performance
perspective.

3. `gethrtime() % 3` can vary in behavior from system to system based on
kernel version, architecture and clock source. In comparison, this
per-CPU PRNG is about ~40 lines of code in `random_get_pseudo_bytes()`
that should behave consistently across all systems regardless of kernel
version, system architecture or machine clock source. It is unlikely
that we would ever need to revisit this per-CPU PRNG while the same
cannot be said for `gethrtime() % 3`.

4. `gethrtime()` uses CPU memory barriers and maybe atomic instructions
depending on the clock source, so replacing `random_get_pseudo_bytes()`
with `gethrtime()` in hot code paths could still require a future person
working on NUMA scalability to reimplement it anyway while this per-CPU
PRNG would not by virtue of using neither CPU memory barriers nor atomic
instructions. Note that I did not check various clock sources for the
presence of atomic instructions. There is simply too much code to read
and given the drawbacks versus this per-cpu PRNG, there is no point in
being certain.

5. I have heard of instances where poor quality pseudo-random numbers
caused problems for HPC code in ways that took more than a year to
identify and were remedied by switching to a higher quality source of
pseudo-random numbers. While filesystems are different than HPC code, I
do not think it is impossible for us to have instances where poor
quality pseudo-random numbers can cause problems. Opting for a well
studied PRNG algorithm that passes tests for statistical randomness over
changing callers to use `gethrtime() % 3` bypasses the need to think
about both whether poor quality pseudo-random numbers can cause problems
and the statistical quality of numbers from `gethrtime() % 3`.

6. `gethrtime()` calls `getrawmonotonic()`, which uses seqlocks. This is
probably not a huge issue, but anyone using kgdb would never be able to
step through a seqlock critical section, which is not a problem either
now or with the per-CPU PRNG:

https://en.wikipedia.org/wiki/Seqlock

The only downside that I can see is that this code's memory requirement
is O(N) where N is NR_CPUS, versus the current code and `gethrtime() %
3`, which are O(1), but that should not be a problem. The seeds will use
64KB of memory at the high end (i.e `NR_CPU == 4096`) and 16 bytes of
memory at the low end (i.e. `NR_CPU == 1`).  In either case, we should
only use a few hundred bytes of code for text, especially since
`spl_rand_jump()` should be inlined into `spl_random_init()`, which
should be removed during early boot as part of "Freeing unused kernel
memory". In either case, the memory requirements are minuscule.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #372
2016-02-17 09:49:09 -08:00
Chunwei Chen 16522ac290 Use tsd to store tq for taskq_member
To prevent taskq_member holding tq_lock and doing linear search, thus causing
contention. We store the taskq pointer to which the thread belongs in tsd.
This way taskq_member will not need to touch tq_lock, and tsd has per slot
spinlock. So the contention should be reduced greatly.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #500
Closes #504
Closes #505
2016-01-20 13:07:45 -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
Chunwei Chen 086476f920 Fix spl_hostid module parameter
Currently, spl_hostid module parameter doesn't do anything, because it will
always be overwritten when calling into hostid_read().
Instead, we should only call into hostid_read() when spl_hostid is not zero,
just as the comment describes.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #427
2015-02-04 16:42:25 -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
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 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 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 bb4dee3df2 Remove utsname() wrapper
There is no longer a need to wrap this because utsname() is provided
by the kernel and can be called directly.  This will require a small
change in the ZFS code because utsname is expected to be a global
structure and not a function.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:11:41 -07:00
Brian Behlendorf 6203295438 Make license compatibility checks consistent
Apply the license specified in the META file to ensure the
compatibility checks are all performed consistently.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2014-10-17 15:07:28 -07:00
Richard Yao ec18fe3ce8 Cleanup vn_rename() and vn_remove()
zfsonlinux/spl#bcb15891ab394e11615eee08bba1fd85ac32e158 implemented
Linux 3.6+ support by adding duplicate vn_rename and vn_remove
functions. The new ones were cleaner, but the duplicate functions made
the codebase less maintainable. This adds some compatibility shims that
allow us to retire the older vn_rename and vn_remove in favor of the new
ones on old kernels. The result is a net 143 line reduction in lines of
code and a cleaner codebase.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #370
2014-08-13 16:25:44 -07:00
Tim Chase 7f23e00109 Add functions and macros as used upstream.
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
2014-07-22 09:47:48 -07:00
Richard Yao acf0ade362 Simplify hostid logic
There is plenty of compatibility code for a hw_hostid
that isn't used by anything. At the same time, there are apparently
issues with the current hostid logic. coredumb in #zfsonlinux on
freenode reported that Fedora 17 changes its hostid on every boot, which
required force importing his pool. A suggestion by wca was to adopt
FreeBSD's behavior, where it treats hostid as zero if /etc/hostid does
not exist

Adopting FreeBSD's behavior permits us to eliminate plenty of code,
including a userland helper that invokes the system's hostid as a
fallback.

Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #224
2014-04-14 09:04:41 -07:00
Brian Behlendorf 921a35adeb Add module versioning
Use the standard Linux MODULE_VERSION macro to expose the installed
spl and splat module versions.  This will also automatically add a
checksum of the .c files and headers in "srcversion".  See:

  /sys/module/spl/version
  /sys/module/spl/srcversion
  /sys/module/splat/version
  /sys/module/splat/srcversion

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1923

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2013-12-06 11:03:43 -08:00
Ned Bass 3d6af2dd6d Refresh links to web site
Update links to refer to the official ZFS on Linux website instead of
@behlendorf's personal fork on github.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2013-03-04 19:09:34 -08:00
Ned Bass 8842263bd0 call_usermodehelper() should wait for process
As of Linux 3.4 the UMH_WAIT_* constants were renumbered.  In
particular, the meaning of "1" changed from UMH_WAIT_PROC (wait for
process to complete), to UMH_WAIT_EXEC (wait for the exec, but not the
process).  A number of call sites used the number 1 instead of the
constant name, so the behavior was not as expected on kernels with
this change.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2013-01-09 16:54:19 -08:00
Brian Behlendorf 034f1b331e Fix spl_kmem_init_kallsyms_lookup() panic
Due to I/O buffering the helper may return successfully before
the proc handler has a chance to execute.  To catch this case
wait up to 1 second to verify spl_kallsyms_lookup_name_fn was
updated to a non SYMBOL_POISON value.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#699
Closes zfsonlinux/zfs#859
2012-12-19 09:06:35 -08:00
Etienne Dechamps a9f2397ee9 Determine the hostid on demand.
Currently, the SPL tries to determine the hostid at module load. The
hostid is usually determined by running the userland program "hostid"
during module initialization.

Unfortunately, when the module initializes, it may be way too soon to be
able to run any userland programs. This is especially true when the
module is compiled directly inside the kernel (built-in); in that case,
the SPL would try to run hostid when the kernel is still initializing,
which of course is doomed to fail.

This patch fixes the issue by deferring hostid generation until
something actually needs the hostid (that is, when zone_get_hostid() is
called), thus switching to a "on-initialization" model to a "on-demand"
(lazy loading) model. ZFS only needs the hostid when some pool
operations are requested, and this always happens way after the kernel
has finished initialization, thus solving the problem.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue zfsonlinux/zfs#851
2012-07-26 15:14:02 -07:00
Brian Behlendorf e8267acd25 32-bit compat, hostid_read()
Explicitly cast the sizeof in hostid_read() to prevent the
following compiler warning on 32-bit systems.

  module/spl/spl-generic.c:490:10: error: format '%lu' expects
  argument of type 'long unsigned int', but argument 4 has type
  'unsigned int' [-Werror=format]

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2012-07-20 11:14:04 -07:00
Jorgen Lundman 93b0dc92ea Fix ARM 64-bit division
Correctly implementating 64-bit division for ARM requires more than
just providing the __aeabi_uldivmod() and __aeabi_ldivmod() symbols.
They are need to be implemented is such a way that the quotient and
remainder and left in specific registers after the division operation
completes.  This change updates the wrapper functions to accomplish
this according to the official ARM Run-time ABI.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#706
2012-05-22 09:27:11 -07:00
Jorgen Lundman ef6f91ce0c Add missing 64-bit divide for 32-bit ARM
Leverage the existing generic 64-bit division operations which
were originally implemented for x86 to support ARM.  All that is
required is to make the symbols available to the linker with the
expected names.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2012-05-03 10:07:54 -07:00
Brian Behlendorf 0835057ee7 Add SPL_META_RELEASE to module load/unload messages
Include the ZFS_META_RELEASE in the module load/unload messages
to more clearly indicate exactly what version of the SPL has
been loaded.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2012-03-23 12:11:50 -07:00
Brian Behlendorf 1114ae6ae7 Prepend spl_ to all init/fini functions
This is a bit of cleanup I'd been meaning to get to for a while
to reduce the chance of a type conflict.  Well that conflict
finally occurred with the kstat_init() function which conflicts
with a function in the 2.6.32-6-pve kernel.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #56
2011-11-11 09:18:28 -08:00
Brian Behlendorf 12ff95ff57 Linux 3.1 compat, kern_path_parent()
Prior to Linux 3.1 the kern_path_parent symbol was exported for
use by kernel modules.  As of Linux 3.1 it is now longer easily
available.  To handle this case the spl will now dynamically
look up address of the missing symbol at module load time.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #52
2011-11-09 16:51:25 -08:00
Brian Behlendorf 6b3b569df3 Remove /etc/hostid missing warning
No longer print the following warning to the console when the
/etc/hostid file is missing.  This is the expected default behavior.
Keeping the hostid in sync with the initramfs is now accomplished
by creating the /etc/hostid in the initramfs not on the system.

  SPL: The /etc/hostid file is not found.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2011-10-06 14:58:09 -07:00
Darik Horn 0d54dcb566 Read the /etc/hostid file directly.
Deprecate the /usr/bin/hostid call by reading the /etc/hostid file
directly. Add the spl_hostid_path parameter to override the default
/etc/hostid path.

Rename the set_hostid() function to hostid_exec() to better reflect
actual behavior and complement the new hostid_read() function.

Use HW_INVALID_HOSTID as the spl_hostid sentinel value because
zero seems to be a valid gethostid() result on Linux.
2011-06-24 09:58:03 -07:00
Darik Horn 5b8f76ea16 Make the SPL kernel messages consistent with ZFS.
Change the SPL kernel messages for module loading and module
unloading so that they are similar to the ZFS kernel messages.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2011-04-21 09:41:13 -07:00
Darik Horn ad35b6a6e9 Remove the gawk dependency.
This reverts commit 1814251453.

Demote the gawk call back to awk and ensure that stderr is attached.  GNU gawk
tolerates a missing stderr handle, but many utilities do not, which could be
why a regular awk call was unexplainably failing on some systems.

Use argv[0] instead of sh_path for consistency internally and with other Linux
drivers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2011-04-21 09:41:09 -07:00
Darik Horn fa6f7d8f9d Import spl_hostid as a module parameter.
Provide a call_usermodehelper() alternative by letting the hostid be passed as
a module parameter like this:

  $ modprobe spl spl_hostid=0x12345678

Internally change the spl_hostid variable to unsigned long because that is the
type that the coreutils /usr/bin/hostid returns.

Move the hostid command into GET_HOSTID_CMD for consistency with the similar
GET_KALLSYMS_ADDR_CMD invocation.

Use argv[0] instead of sh_path for consistency internally and with other Linux
drivers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2011-04-21 09:41:01 -07:00
Brian Behlendorf 5c1967ebe2 Fix zlib compression
While portions of the code needed to support z_compress_level() and
z_uncompress() where in place.  In reality the current implementation
was non-functional, it just was compilable.

The critical missing component was to setup a workspace for the
compress/uncompress stream structures to use.  A kmem_cache was
added for the workspace area because we require a large chunk
of memory.  This avoids to need to continually alloc/free this
memory and vmap() the pages which is very slow.  Several objects
will reside in the per-cpu kmem_cache making them quick to acquire
and release.  A further optimization would be to adjust the
implementation to additional ensure the memory is local to the cpu.
Currently that may not be the case.
2011-02-25 16:56:22 -08:00
Brian Behlendorf 9fe45dc1ac Add Thread Specific Data (TSD) Implementation
Thread specific data has implemented using a hash table, this avoids
the need to add a member to the task structure and allows maximum
portability between kernels.  This implementation has been optimized
to keep the tsd_set() and tsd_get() times as small as possible.

The majority of the entries in the hash table are for specific tsd
entries.  These entries are hashed by the product of their key and
pid because by design the key and pid are guaranteed to be unique.
Their product also has the desirable properly that it will be uniformly
distributed over the hash bins providing neither the pid nor key is zero.
Under linux the zero pid is always the init process and thus won't be
used, and this implementation is careful to never to assign a zero key.
By default the hash table is sized to 512 bins which is expected to
be sufficient for light to moderate usage of thread specific data.

The hash table contains two additional type of entries.  They first
type is entry is called a 'key' entry and it is added to the hash during
tsd_create().  It is used to store the address of the destructor function
and it is used as an anchor point.  All tsd entries which use the same
key will be linked to this entry.  This is used during tsd_destory() to
quickly call the destructor function for all tsd associated with the key.
The 'key' entry may be looked up with tsd_hash_search() by passing the
key you wish to lookup and DTOR_PID constant as the pid.

The second type of entry is called a 'pid' entry and it is added to the
hash the first time a process set a key.  The 'pid' entry is also used
as an anchor and all tsd for the process will be linked to it.  This
list is using during tsd_exit() to ensure all registered destructors
are run for the process.  The 'pid' entry may be looked up with
tsd_hash_search() by passing the PID_KEY constant as the key, and
the process pid.  Note that tsd_exit() is called by thread_exit()
so if your using the Solaris thread API you should not need to call
tsd_exit() directly.
2010-12-07 10:02:32 -08:00
Ricardo M. Correia 81672c0122 Display DEBUG keyword during module load when --enable-debug is used.
Signed-off-by: Ricardo M. Correia <ricardo.correia@oracle.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-07-20 15:31:03 -07:00
Brian Behlendorf b17edc10a9 Prefix all SPL debug macros with 'S'
To avoid conflicts with symbols defined by dependent packages
all debugging symbols have been prefixed with a 'S' for SPL.
Any dependent package needing to integrate with the SPL debug
should include the spl-debug.h header and use the 'S' prefixed
macros.  They must also build with DEBUG defined.
2010-07-20 13:30:40 -07:00
Brian Behlendorf 55abb0929e Split <sys/debug.h> header
To avoid symbol conflicts with dependent packages the debug
header must be split in to several parts.  The <sys/debug.h>
header now only contains the Solaris macro's such as ASSERT
and VERIFY.  The spl-debug.h header contain the spl specific
debugging infrastructure and should be included by any package
which needs to use the spl logging.  Finally the spl-trace.h
header contains internal data structures only used for the log
facility and should not be included by anythign by spl-debug.c.

This way dependent packages can include the standard Solaris
headers without picking up any SPL debug macros.  However, if
the dependant package want to integrate with the SPL debugging
subsystem they can then explicitly include spl-debug.h.

Along with this change I have dropped the CHECK_STACK macros
because the upstream Linux kernel now has much better stack
depth checking built in and we don't need this complexity.

Additionally SBUG has been replaced with PANIC and provided as
part of the Solaris macro set.  While the Solaris version is
really panic() that conflicts with the Linux kernel so we'll
just have to make due to PANIC.  It should rarely be called
directly, the prefered usage would be an ASSERT or VERIFY.

There's lots of change here but this cleanup was overdue.
2010-07-20 13:29:35 -07:00
Brian Behlendorf a4bfd8ea1b Add __divdi3(), remove __udivdi3() kernel dependency
Up until now no SPL consumer attempted to perform signed 64-bit
division so there was no need to support this.  That has now
changed so I adding 64-bit division support for 32-bit platforms.
The signed implementation is based on the unsigned version.

Since the have been several bug reports in the past concerning
correct 64-bit division on 32-bit platforms I added some long
over due regression tests.  Much to my surprise the unsigned
64-bit division regression tests failed.

This was surprising because __udivdi3() was implemented by simply
calling div64_u64() which is provided by the kernel.  This meant
that the linux kernels 64-bit division algorithm on 32-bit platforms
was flawed.  After some investigation this turned out to be exactly
the case.

Because of this I was forced to abandon the kernel helper and
instead to fully implement 64-bit division in the spl.  There are
several published implementation out there on how to do this
properly and I settled on one proposed in the book Hacker's Delight.
Their proposed algoritm is freely available without restriction
and I have just modified it to be linux kernel friendly.

The update implementation now passed all the unsigned and signed
regression tests.  This should be functional, but not fast, which is
good enough for out purposes.  If you want fast too I'd strongly
suggest you upgrade to a 64-bit platform.  I have also reported the
kernel bug and we'll see if we can't get it fixed up stream.
2010-07-13 16:44:02 -07:00
Brian Behlendorf 1814251453 Require gawk the usermode helper fails with awk
For some reason when awk invoked by the usermode helper the command
always fails.  Interestingly gawk does not suffer from this problem
which is why I never observed this failure since the distro I tested
with all had gawk installed instead of awk.  Anyway, the simplest
thing to do here is to just make gawk mandatory.  I've added a
configure check for gawk specifically and have updated the command
to call gawk not awk.
2010-07-01 16:38:08 -07:00
Ned Bass 1a73940d39 Initialize the /dev/splatctl device buffer
On open() and initialize the buffer with the SPL version string.  The
user space splat utility expects to find the SPL version string when
it opens and reads from /dev/splatctl.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-07-01 10:59:46 -07:00
Brian Behlendorf ae4c36adce Cleanly split Linux proc.h (fs) from conflicting Solaris proc.h (process)
Under linux the proc.h header is for the /proc filesystem, and under
Solaris the proc/h header if for processes.  This patch correctly
moves the Linux proc functionality in a linux/proc_compat.h header
and leaves the sys/proc.h for use by Solaris.  Minor updates were
required to all the call sites where it was included of course.
2010-06-11 15:57:25 -07:00
Alex Zhuravlev 1b4ad25e2f Stack overflow on 64-bit modulus operations on 32-bit architectures.
Running 'zpool create' on a 32-bit machine with an SPL compiled with
gcc 4.4.4 led to a stack overlow.  This turned out to be due to some
sort of 'optimization' by gcc:

uint64_t __umoddi3(uint64_t dividend, uint64_t divisor)
{
   return dividend - divisor * (dividend / divisor);
}

This code was supposed to be using __udivdi3 to implement /, but gcc
instead implemented it via __umoddi3 itself.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-06-03 09:06:55 -07:00
Brian Behlendorf 716154c592 Public Release Prep
Updated AUTHORS, COPYING, DISCLAIMER, and INSTALL files.  Added
standardized headers to all source file to clearly indicate the
copyright, license, and to give credit where credit is due.
2010-05-17 15:18:00 -07:00
Brian Behlendorf 82a358d9c0 Update vn_set_pwd() to allow user|kernal address for filename
During module init spl_setup()->The vn_set_pwd("/") was failing
with -EFAULT because user_path_dir() and __user_walk() both
expect 'filename' to be a user space address and it's not in
this case.  To handle this the data segment size is increased
to to ensure strncpy_from_user() does not fail with -EFAULT.

Additionally, I've added a printk() warning to catch this and
log it to the console if it ever reoccurs.  I thought everything
was working properly here because there consequences of this
failing are subtle and usually non-critical.
2010-04-22 12:53:58 -07:00