Commit Graph

57 Commits

Author SHA1 Message Date
Alexander Motin
efdfb14fc8 Remove pool io kstats
This mostly reverts "3537 want pool io kstats" commit of 8 years ago.

From one side this code using pool-wide locks became pretty bad for
performance, creating significant lock contention in I/O pipeline.
From another, there are more efficient ways now to obtain detailed
statistics, while this statistics is illumos-specific and much less
usable on Linux and FreeBSD, reported only via procfs/sysctls.

This commit does not remove KSTAT_TYPE_IO implementation, that may
be removed later together with already unused KSTAT_TYPE_INTR and
KSTAT_TYPE_TIMER.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12212
2021-06-10 10:50:16 -07:00
Brian Behlendorf
af80160f48 Linux: Set spl_kmem_cache_slab_limit when page size !4K
For small objects the kernel's slab implementation is very fast and
space efficient. However, as the allocation size increases to
require multiple pages performance suffers. The SPL kmem cache
allocator was designed to better handle these large allocation
sizes. Therefore, on Linux the kmem_cache_* compatibility wrappers
prefer to use the kernel's slab allocator for small objects and
the custom SPL kmem cache allocator for larger objects.

This logic was effectively disabled for all architectures using
a non-4K page size which caused all kmem caches to only use the
SPL implementation. Functionally this is fine, but the SPL code
which calculates the target number of objects per-slab does not
take in to account that __vmalloc() always returns page-aligned
memory. This can result in a massive amount of wasted space when
allocating tiny objects on a platform using large pages (64k).

To resolve this issue we set the spl_kmem_cache_slab_limit cutoff
to 16K for all architectures. 

This particular change does not attempt to update the logic used
to calculate the optimal number of pages per slab. This remains
an issue which should be addressed in a future change.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #12152
Closes #11429
Closes #11574
Closes #12150
2021-06-09 13:05:34 -07:00
наб
2fe8060cee spl-module-parameters.5: remove spl_kmem_cache_{expire,obj_per_slab_min}
Both were removed in 4fbdb10c7b ("remove
kmem_cache module parameter KMC_EXPIRE_AGE")

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12157
2021-06-09 13:05:34 -07:00
наб
7cdd4dd33b linux: don't fall through to 3-arg vfs_getattr
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12103
2021-05-27 22:31:57 -07:00
наб
bdcf0cca10 linux/spl: proc: use global table_{min,max} values instead of local ones
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #11879
2021-04-19 15:22:57 -07:00
наб
e5c4f86e7a linux/spl: base proc_dohostid() on proc_dostring()
This fixes /proc/sys/kernel/spl/hostid on kernels with mainline commit
32927393dc1ccd60fb2bdc05b9e8e88753761469 ("sysctl: pass kernel pointers
to ->proc_handler") ‒ 5.7-rc1 and up

The access_ok() check in copy_to_user() in proc_copyout_string() would
always fail, so all userspace reads and writes would fail with EINVAL

proc_dostring() strips only the final new-line,
but simple_strtoul() doesn't actually need a back-trimmed string ‒
writing "012345678   \n" is still allowed, as is "012345678zupsko", &c.

This alters what happens when an invalid value is written ‒
previously it'd get set to what-ever simple_strtoul() returned
(probably 0, thereby resetting it to default), now it does nothing

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #11878
Closes #11879
2021-04-19 15:22:57 -07:00
Paul Dagnelie
d682e20ba4 Add SIGSTOP and SIGTSTP handling to issig
This change adds SIGSTOP and SIGTSTP handling to the issig function; 
this mirrors its behavior on Solaris. This way, long running kernel 
tasks can be stopped with the appropriate signals. Note that doing 
so with ctrl-z on the command line doesn't return control of the tty 
to the shell, because tty handling is done separately from stopping 
the process. That can be future work, if people feel that it is a 
necessary addition.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Issue #810 
Issue #10843 
Closes #11801
2021-04-19 15:12:33 -07:00
Brian Behlendorf
0e6c493fec cppcheck: integrete cppcheck
In order for cppcheck to perform a proper analysis it needs to be
aware of how the sources are compiled (source files, include
paths/files, extra defines, etc).  All the needed information is
available from the Makefiles and can be leveraged with a generic
cppcheck Makefile target.  So let's add one.

Additional minor changes:

* Removing the cppcheck-suppressions.txt file.  With cppcheck 2.3
  and these changes it appears to no longer be needed.  Some inline
  suppressions were also removed since they appear not to be
  needed.  We can add them back if it turns out they're needed
  for older versions of cppcheck.

* Added the ax_count_cpus m4 macro to detect at configure time how
  many processors are available in order to run multiple cppcheck
  jobs.  This value is also now used as a replacement for nproc
  when executing the kernel interface checks.

* "PHONY =" line moved in to the Rules.am file which is included
  at the top of all Makefile.am's.  This is just convenient becase
  it allows us to use the += syntax to add phony targets.

* One upside of this integration worth mentioning is it now allows
  `make cppcheck` to be run in any directory to check that subtree.

* For the moment, cppcheck is not run against the FreeBSD specific
  kernel sources.  The cppcheck-FreeBSD target will need to be
  implemented and testing on FreeBSD to support this.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11508
2021-01-26 16:12:26 -08:00
Brian Behlendorf
a06ba74a1e cppcheck: return value always 0
Identical condition and return expression 'rc', return value is
always 0.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11508
2021-01-26 16:12:18 -08:00
Brian Behlendorf
2cdd75bed7 cppcheck: remove redundant ASSERTs
The ASSERT that the passed pointer isn't NULL appears after the
pointer has already been dereferenced.  Remove the redundant check.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11508
2021-01-26 16:12:10 -08:00
Matthew Macy
a4134da2b2
spl-taskq: Make sure thread tsd hash entry is cleared
Like any other thread created by thread_create() we need to call
thread_exit() to properly clean it up.  In particular, this ensures the
tsd hash for the thread is cleared.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #11512
2021-01-25 11:18:28 -08:00
Paul Dagnelie
60a4c7d2a2
Implement memory and CPU hotplug
ZFS currently doesn't react to hotplugging cpu or memory into the 
system in any way. This patch changes that by adding logic to the ARC 
that allows the system to take advantage of new memory that is added 
for caching purposes. It also adds logic to the taskq infrastructure 
to support dynamically expanding the number of threads allocated to a 
taskq.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Matthew Ahrens <matthew.ahrens@delphix.com>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #11212
2020-12-10 14:09:23 -08:00
Brian Behlendorf
d0249a4bd0
Replace ZFS on Linux references with OpenZFS
This change updates the documentation to refer to the project
as OpenZFS instead ZFS on Linux.  Web links have been updated
to refer to https://github.com/openzfs/zfs.  The extraneous
zfsonlinux.org web links in the ZED and SPL sources have been
dropped.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11007
2020-10-08 20:10:13 -07:00
Brian Behlendorf
266d1121c3
Fix buggy procfs_list_seq_next warning
The kernel seq_read() helper function expects ->next() to update
the passed position even there are no more entries.  Failure to
do so results in the following warning being logged.

    seq_file: buggy .next function procfs_list_seq_next [spl]
    did not update position index

Functionally there is no issue with the way procfs_list_seq_next()
is implemented and the warning is harmless.  However, we want to
silence this some what scary incorrect warning.  This commit
updates the Linux procfs code to advance the position even for
the last entry.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #10984 
Closes #10996
2020-09-30 13:27:51 -07:00
Matthew Macy
7b8363d7f0
FreeBSD: Add support for procfs_list
The procfs_list interface is required by several kstats. Implement
this functionality for FreeBSD to provide access to these kstats.
                           
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10890
2020-09-23 16:43:51 -07:00
Matthew Macy
ac6e5fb202
Replace cv_{timed}wait_sig with cv_{timed}wait_idle where appropriate
There are a number of places where cv_?_sig is used simply for
accounting purposes but the surrounding code has no ability to
cope with actually receiving a signal. On FreeBSD it is possible
to send signals to individual kernel threads so this could
enable undesirable behavior.

This patch adds routines on Linux that will do the same idle
accounting as _sig without making the task interruptible. On
FreeBSD cv_*_idle  are all aliases for cv_*

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10843
2020-09-03 20:04:09 -07:00
Spencer Kinny
6fffc88bf3
Links in Source Files
Added comments in following files
with links to Illumos manual pages:

./module/avl/avl.c
./module/nvpair/nvpair.c
./module/os/linux/spl/spl-kstat.c
./module/os/freebsd/spl/spl_kstat.c

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Spencer Kinny <spencerkinny1995@gmail.com>
Closes #5113 
Closes #10859
2020-09-02 09:42:12 -07:00
Matthew Ahrens
994de7e4b7
Remove KMC_KMEM and KMC_VMEM
`KMC_KMEM` and `KMC_VMEM` are now unused since all SPL-implemented
caches are `KMC_KVMEM`.

KMC_KMEM: Given the default value of `spl_kmem_cache_kmem_limit`, we
don't use kmalloc to back the SPL caches, instead we use kvmalloc
(KMC_KVMEM).  The flag, module parameter, /proc entries, and associated
code are removed.

KMC_VMEM: This flag is not used, and kvmalloc() is always preferable to
vmalloc().  The flag, /proc entries, and associated code are removed.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10673
2020-08-17 16:04:28 -07:00
Matthew Ahrens
c6f2b942be Remove KMC_NOMAGAZINE
Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
2020-08-05 10:28:07 -07:00
Matthew Ahrens
3c09f6949a Remove KMC_QCACHE
Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
2020-08-05 10:28:01 -07:00
Matthew Ahrens
d519c10575 Remove KMC_NOHASH
Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
2020-08-05 10:27:56 -07:00
Matthew Ahrens
f68af67a0c Remove KMC_NOTOUCH
Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
2020-08-05 10:27:46 -07:00
Matthew Ahrens
492db125dc Remove KMC_OFFSLAB
Remove dead code to make the implementation easier to understand.

Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes #10650
2020-08-05 10:25:37 -07:00
Matthew Ahrens
4fbdb10c7b
remove kmem_cache module parameter KMC_EXPIRE_AGE
By default, `spl_kmem_cache_expire` is `KMC_EXPIRE_MEM`, meaning that
objects will be removed from kmem cache magazines by
`spl_kmem_cache_reap_now()`.

There is also a module parameter to change this to `KMC_EXPIRE_AGE`,
which establishes a maximum lifetime for objects to stay in the
magazine.  This setting has rarely, if ever, been used, and is not
regularly tested.

This commit removes the code for `KMC_EXPIRE_AGE`, and associated module
parameters.

Additionally, the unused module parameter
`spl_kmem_cache_obj_per_slab_min` is removed.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10608
2020-07-24 09:39:26 -07:00
Matthew Ahrens
026e529cb3
Remove skc_reclaim, hdr_recl, kmem_cache shrinker
The SPL kmem_cache implementation provides a mechanism, `skc_reclaim`,
whereby individual caches can register a callback to be invoked when
there is memory pressure.  This mechanism is used in only one place: the
ARC registers the `hdr_recl()` reclaim function.  This function wakes up
the `arc_reap_zthr`, whose job is to call `kmem_cache_reap()` and
`arc_reduce_target_size()`.

The `skc_reclaim` callbacks are invoked only by shrinker callbacks and
`arc_reap_zthr`, and only callback only wakes up `arc_reap_zthr`.  When
called from `arc_reap_zthr`, waking `arc_reap_zthr` is a no-op.  When
called from shrinker callbacks, we are already aware of memory pressure
and responding to it.  Therefore there is little benefit to ever calling
the `hdr_recl()` `skc_reclaim` callback.

The `arc_reap_zthr` also wakes once a second, and if memory is low when
allocating an ARC buffer.  Therefore, additionally waking it from the
shrinker calbacks has little benefit.

The shrinker callbacks can be invoked very frequently, e.g. 10,000 times
per second.  Additionally, for invocation of the shrinker callback,
skc_reclaim is invoked many times.  Therefore, this mechanism consumes
significant amounts of CPU time.

The kmem_cache shrinker calls `spl_kmem_cache_reap_now()`, which,
in addition to invoking `skc_reclaim()`, does two things to attempt to
free pages for use by the system:
 1. Return free objects from the magazine layer to the slab layer
 2. Return entirely-free slabs to the page layer (i.e. free pages)

These actions apply only to caches implemented by the SPL, not those
that use the underlying kernel SLAB/SLUB caches.  The SPL caches are
used for objects >=32KB, which are primarily linear ABD's cached in the
DBUF cache.

These actions (freeing objects from the magazine layer and returning
entirely-free slabs) are also taken whenever a `kmem_cache_free()` call
finds a full magazine.  So there would typically be zero entirely-free
slabs, and the number of objects in magazines is limited (typically no
more than 64 objects per magazine, and there's one magazine per CPU).
Therefore the benefit of `spl_kmem_cache_reap_now()`, while nonzero, is
modest.

We also call `spl_kmem_cache_reap_now()` from the `arc_reap_zthr`, when
memory pressure is detected.  Therefore, calling
`spl_kmem_cache_reap_now()` from the kmem_cache shrinker is not needed.

This commit removes the `skc_reclaim` mechanism, its only callback
`hdr_recl()`, and the kmem_cache shrinker callback.

Reviewed-By: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10576
2020-07-19 09:58:30 -07:00
Romain Dolbeau
01a4852ecb
Fix early include of <linux/percpu_compat.h>
Move/add include of <linux/percpu_compat.h> to satisfy missing
requirements.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain@dolbeau.org>
Closes #10568 
Closes #10569
2020-07-15 15:58:15 -07:00
Matthew Ahrens
3c42c9ed84
Clean up OS-specific ARC and kmem code
OS-specific code (e.g. under `module/os/linux`) does not need to share
its code structure with any other operating systems.  In particular, the
ARC and kmem code need not be similar to the code in illumos, because we
won't be syncing this OS-specific code between operating systems.  For
example, if/when illumos support is added to the common repo, we would
add a file `module/os/illumos/zfs/arc_os.c` for the illumos versions of
this code.

Therefore, we can simplify the code in the OS-specific ARC and kmem
routines.

These changes do not impact system behavior, they are purely code
cleanup.  The changes are:

Arenas are not used on Linux or FreeBSD (they are always `NULL`), so
`heap_arena`, `zio_arena`, and `zio_alloc_arena` can be removed, along
with code that uses them.

In `arc_available_memory()`:
 * `desfree` is unused, remove it
 * rename `freemem` to avoid conflict with pre-existing `#define`
 * remove checks related to arenas
 * use units of bytes, rather than converting from bytes to pages and
   then back to bytes

`SPL_KMEM_CACHE_REAP` is unused, remove it.

`skc_reap` is unused, remove it.

The `count` argument to `spl_kmem_cache_reap_now()` is unused, remove
it.

`vmem_size()` and associated type and macros are unused, remove them.

In `arc_memory_throttle()`, use a less confusing variable name to store
the result of `arc_free_memory()`.

Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10499
2020-06-29 09:01:07 -07:00
Matthew Ahrens
270ece24b6
Revise SPL wrapper for shrinker callbacks
The SPL provides a wrapper for the kernel's shrinker callbacks, which
enables the ZFS code to interface with multiple versions of the shrinker
API's from different kernel versions.  Specifically, Linux kernels 3.0 -
3.11 has a single "combined" callback, and Linux kernels 3.12 and later
have two "split" callbacks.  The SPL provides a wrapper function so that
the ZFS code only needs to implement one version of the callbacks.

Currently the SPL's wrappers are designed such that the ZFS code
implements the older, "combined" callback.  There are a few downsides to
this approach:

* The general design within ZFS is for the latest Linux kernel to be
considered the "first class" API.

* The newer, "split" callback API is easier to understand, because each
callback has one purpose.

* The current wrappers do not completely abstract out the differing
API's, so ZFS code needs `#ifdef` code to handle the differing return
values required for different kernel versions.

This commit addresses these drawbacks by having the ZFS code provide the
latest, "split" callbacks, and the SPL provides a wrapping function for
the older, "combined" API.

Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10502
2020-06-27 10:27:02 -07:00
Serapheim Dimitropoulos
ec1fea4516
Use percpu_counter for obj_alloc counter of Linux-backed caches
A previous commit enabled the tracking of object allocations
in Linux-backed caches from the SPL layer for debuggability.
The commit is: 9a170fc6fe54f1e852b6c39630fe5ef2bbd97c16

Unfortunately, it also introduced minor performance regressions
that were highlighted by the ZFS perf test-suite. Within Delphix
we found that the regression would be from -1%, all the way up
to -8% for some workloads.

This commit brings performance back up to par by creating a
separate counter for those caches and making it a percpu in
order to avoid lock-contention.

The initial performance testing was done by myself, and the
final round was conducted by @tonynguien who was also the one
that discovered the regression and highlighted the culprit.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10397
2020-06-26 18:06:50 -07:00
Arvind Sankar
c0673571d0 Switch off -Wmissing-prototypes for libgcc math functions
spl-generic.c defines some of the libgcc integer library functions on
32-bit. Don't bother checking -Wmissing-prototypes since nothing should
directly call these functions from C code.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:21:46 -07:00
Arvind Sankar
60356b1a21 Add include files for prototypes
Include the header with prototypes in the file that provides definitions
as well, to catch any mismatch between prototype and definition.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:21:25 -07:00
Arvind Sankar
65c7cc49bf Mark functions as static
Mark functions used only in the same translation unit as static. This
only includes functions that do not have a prototype in a header file
either.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470
2020-06-18 12:20:38 -07:00
Matthew Macy
8056a75672
Disambiguate condvar API contract
On Illumos callers of cv_timedwait and cv_timedwait_hires
can't distinguish between whether or not the cv was signaled
or the call timed out. Illumos handles this (for some definition
of handles) by calling cv_signal in the return path if we were
signaled but the return value indicates instead that we timed
out. This would make sense if it were possible to query the the
cv for its net signal disposition. However, this isn't possible
and, in spite of the fact that there are places in the code that
clearly take a different and incompatible path if a timeout value
is indicated, this distinction appears to be rather subtle to most
developers. This problem is further compounded by the fact that on
Linux, calling cv_signal in the return path wouldn't even do the
right thing unless there are other waiters.

Since it is possible for the caller to independently determine how
much time is remaining but it is not possible to query if the cv
was in fact signaled, prioritizing signalling over timeout seems
like a cleaner solution. In addition, judging from usage patterns
within the code itself, it is also less error prone.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10471
2020-06-18 10:17:50 -07:00
Michael Niewöhner
32f26eaa70
Move GFP flags kernel compatibility code
Move the GFP flags kernel compat code from c file to kmem header.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #10424
2020-06-08 16:33:46 -07:00
Michael Niewöhner
080102a1b6
Linux 5.8 compat: __vmalloc()
The `pgprot` argument has been removed from `__vmalloc` in Linux 5.8,
being `PAGE_KERNEL` always now [1].

Detect this during configure and define a wrapper for older kernels.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/mm/vmalloc.c?h=next-20200605&id=88dca4ca5a93d2c09e5bbc6a62fbfc3af83c4fca

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Co-authored-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #10422
2020-06-08 16:32:02 -07:00
Matthew Ahrens
b3212d2fa6
Improve performance of zio_taskq_member
__zio_execute() calls zio_taskq_member() to determine if we are running
in a zio interrupt taskq, in which case we may need to switch to
processing this zio in a zio issue taskq.  The call to
zio_taskq_member() can become a performance bottleneck when we are
processing a high rate of zio's.

zio_taskq_member() calls taskq_member() on each of the zio interrupt
taskqs, of which there are 21.  This is slow because each call to
taskq_member() does tsd_get(taskq_tsd), which on Linux is relatively
slow.

This commit improves the performance of zio_taskq_member() by having it
cache the value of tsd_get(taskq_tsd), reducing the number of those
calls to 1/21th of the current behavior.

In a test case running `zfs send -c >/dev/null` of a filesystem with
small blocks (average 2.5KB/block), zio_taskq_member() was using 6.7% of
one CPU, and with this change it is reduced to 1.3%.  Overall time to
perform the `zfs send` reduced by 10% (~150,000 block/sec to ~165,000
blocks/sec).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10070
2020-03-03 10:29:38 -08:00
Matthew Ahrens
2adc6b35ae
Missed wakeup when growing kmem cache
When growing the size of a (VMEM or KVMEM) kmem cache, spl_cache_grow()
always does taskq_dispatch(spl_cache_grow_work), and then waits for the
KMC_BIT_GROWING to be cleared by the taskq thread.

The taskq thread (spl_cache_grow_work()) does:
1. allocate new slab and add to list
2. wake_up_all(skc_waitq)
3. clear_bit(KMC_BIT_GROWING)

Therefore, the waiting thread can wake up before GROWING has been
cleared.  It will see that the growing has not yet completed, and go
back to sleep until it hits the 100ms timeout.

This can have an extreme performance impact on workloads that alloc/free
more than fits in the (statically-sized) magazines.  These workloads
allocate and free slabs with high frequency.

The problem can be observed with `funclatency spl_cache_grow`, which on
some workloads shows that 99.5% of the time it takes <64us to allocate
slabs, but we spend ~70% of our time in outliers, waiting for the 100ms
timeout.

The fix is to do `clear_bit(KMC_BIT_GROWING)` before
`wake_up_all(skc_waitq)`.

A future investigation should evaluate if we still actually need to
taskq_dispatch() at all, and if so on which kernel versions.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #9989
2020-02-13 11:23:02 -08:00
Brian Behlendorf
0dd7364853 Linux 5.6 compat: struct proc_ops
The proc_ops structure was introduced to replace the use of of the
file_operations structure when registering proc handlers.  This
change creates a new kstat_proc_op_t typedef for compatibility
which can be used to pass around the correct structure.

This change additionally adds the 'const' keyword to all of the
existing proc operations structures.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9961
2020-02-07 11:03:53 -08:00
Romain Dolbeau
77122f9d68
Replace static per-cpu with dynamic per-cpu data
This solves the issue of loading the spl module on RISC-V.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Romain Dolbeau <romain.dolbeau@european-processor-initiative.eu>
Closes #9942
2020-02-06 09:26:13 -08:00
loli10K
7e2da7786e KMC_KVMEM disrupts kv_alloc() memory alignment expectations
On kernels with KASAN enabled the following failure can be observed as
soon as the zfs module is loaded:

  VERIFY(IS_P2ALIGNED(ptr, PAGE_SIZE)) failed
  PANIC at spl-kmem-cache.c:228:kv_alloc()

The problem is kmalloc() has never guaranteed aligned allocations; this
requirement resulted in zfsonlinux/spl@8b45dda which removed all
kmalloc() usage in kv_alloc().

Until a GFP_ALIGNED flag (or equivalent functionality) is provided by
the kernel this commit partially reverts 66955885 and 6d948c35 to
prevent k(v)malloc() allocations in kv_alloc().

Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #9813
2020-01-14 09:09:59 -08:00
Brian Behlendorf
e458fcca75
Change http://zfsonlinux.org links to https://zfsonlinux.org
Update the project website links contained in to repository to
reference the secure https://zfsonlinux.org address.

Reviewed-By: Richard Laager <rlaager@wiktel.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Garrett Fields <ghfields@gmail.com>
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9837
2020-01-13 16:43:59 -08:00
Ubuntu
abfdb83607 cppcheck: (error) Shifting signed 64-bit value by 63 bits
As of cppcheck 1.82 surpress the warning regarding shifting too many
bits for __divdi3() implemention.  The algorithm used here is correct.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9732
2019-12-18 17:24:42 -08:00
Ubuntu
7cf1fe6331 cppcheck: (error) Uninitialized variable
As of cppcheck 1.82 warnings are issued when using the list_for_each_*
functions with an uninitialized variable.  Functionally, this is fine
but to resolve the warning initialize these variables.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9732
2019-12-18 17:24:29 -08:00
Matthew Macy
da92d5cbb3 Add zfs_file_* interface, remove vnodes
Provide a common zfs_file_* interface which can be implemented on all 
platforms to perform normal file access from either the kernel module
or the libzpool library.

This allows all non-portable vnode_t usage in the common code to be 
replaced by the new portable zfs_file_t.  The associated vnode and
kobj compatibility functions, types, and macros have been removed
from the SPL.  Moving forward, vnodes should only be used in platform
specific code when provided by the native operating system.

Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9556
2019-11-21 09:32:57 -08:00
Michael Niewöhner
8aaa10a9a0 Check for __GFP_RECLAIM instead of GFP_KERNEL
Check for __GFP_RECLAIM instead of GFP_KERNEL because zfs modifies
IO and FS flags which breaks the check for GFP_KERNEL.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #9034
2019-11-13 10:05:23 -08:00
Michael Niewöhner
6d948c3519 Add kmem_cache flag for forcing kvmalloc
This adds a new KMC_KVMEM flag was added to enforce use of the
kvmalloc allocator in kmem_cache_create even for large blocks, which
may also increase performance in some specific cases (e.g. zstd), too.

Default to KVMEM instead of VMEM in spl_kmem_cache_create.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #9034
2019-11-13 10:05:23 -08:00
Michael Niewöhner
66955885e2 Make use of kvmalloc if available and fix vmem_alloc implementation
This patch implements use of kvmalloc for GFP_KERNEL allocations, which
may increase performance if the allocator is able to allocate physical
memory, if kvmalloc is available as a public kernel interface (since
v4.12). Otherwise it will simply fall back to virtual memory (vmalloc).

Also fix vmem_alloc implementation which can lead to slow allocations
since the first attempt with kmalloc does not make use of the noretry
flag but tells the linux kernel to retry several times before it fails.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #9034
2019-11-13 10:05:10 -08:00
Michael Niewöhner
c025008df5 Add missing documentation for some KMC flags
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #9034
2019-11-13 09:34:51 -08:00
Brian Behlendorf
066e825221
Linux compat: Minimum kernel version 3.10
Increase the minimum supported kernel version from 2.6.32 to 3.10.
This removes support for the following Linux enterprise distributions.

    Distribution     | Kernel | End of Life
    ---------------- | ------ | -------------
    Ubuntu 12.04 LTS | 3.2    | Apr 28, 2017
    SLES 11          | 3.0    | Mar 32, 2019
    RHEL / CentOS 6  | 2.6.32 | Nov 30, 2020

The following changes were made as part of removing support.

* Updated `configure` to enforce a minimum kernel version as
  specified in the META file (Linux-Minimum: 3.10).

    configure: error:
        *** Cannot build against kernel version 2.6.32.
        *** The minimum supported kernel version is 3.10.

* Removed all `configure` kABI checks and matching C code for
  interfaces which solely predate the Linux 3.10 kernel.

* Updated all `configure` kABI checks to fail when an interface is
  missing which was in the 3.10 kernel up to the latest 5.1 kernel.
  Removed the HAVE_* preprocessor defines for these checks and
  updated the code to unconditionally use the verified interface.

* Inverted the detection logic in several kABI checks to match
  the new interface as it appears in 3.10 and newer and not the
  legacy interface.

* Consolidated the following checks in to individual files. Due
  the large number of changes in the checks it made sense to handle
  this now.  It would be desirable to group other related checks in
  the same fashion, but this as left as future work.

  - config/kernel-blkdev.m4 - Block device kABI checks
  - config/kernel-blk-queue.m4 - Block queue kABI checks
  - config/kernel-bio.m4 - Bio interface kABI checks

* Removed the kABI checks for sops->nr_cached_objects() and
  sops->free_cached_objects().  These interfaces are currently unused.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9566
2019-11-12 08:59:06 -08:00
Prakash Surya
ae38e00968 Add tracepoints for taskq entry lifetime events
This adds some new DTRACE_PROBE* endpoints so that we can observe taskq
latencies on a system. Additionally, a new "taskqlatency.bt" script is
added to do this observation via "bpftrace". Lastly, a "zfs-trace.sh"
script is added to wrap "bpftrace" with the proper options required to
run and use "taskqlatency.bt".

For example, with these changes in place, a user can run the following:

    $ cd ./contrib/bpftrace
    $ sudo ./zfs-trace.sh taskqlatency.bt
    Attaching 6 probes...
    ^C

Here's some example output, showing latency information for time spent
executing the taskq entry's function:

    @exec_lat_us[dp_sync_taskq, userquota_updates_task]:
    [2, 4)                 5 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [4, 8)                 0 |                                                    |
    [8, 16)                1 |@@@@@@@@@@                                          |
    [16, 32)               2 |@@@@@@@@@@@@@@@@@@@@                                |

    @exec_lat_us[z_wr_int_h, zio_execute]:
    [8, 16)               16 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [16, 32)               2 |@@@@@@                                              |

    @exec_lat_us[z_wr_iss_h, zio_execute]:
    [16, 32)               4 |@@@@@@@@@@@@@@@@                                    |
    [32, 64)              13 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [64, 128)              1 |@@@@                                                |

    @exec_lat_us[z_ioctl_int, zio_execute]:
    [2, 4)                 1 |@@@@                                                |
    [4, 8)                11 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [8, 16)                8 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@               |

    @exec_lat_us[dp_sync_taskq, sync_dnodes_task]:
    [2, 4)                 1 |@@@@@@                                              |
    [4, 8)                 7 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@       |
    [8, 16)                8 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [16, 32)               2 |@@@@@@@@@@@@@                                       |
    [32, 64)               4 |@@@@@@@@@@@@@@@@@@@@@@@@@@                          |
    [64, 128)              1 |@@@@@@                                              |
    [128, 256)             0 |                                                    |
    [256, 512)             1 |@@@@@@

Here's some example output, showing latency information for time spent
waiting on the taskq, prior to starting execution of entry's function:

    @queue_lat_us[dp_sync_taskq]:
    [2, 4)                 1 |@@@@                                                |
    [4, 8)                 7 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@                      |
    [8, 16)                2 |@@@@@@@@                                            |
    [16, 32)               3 |@@@@@@@@@@@@@                                       |
    [32, 64)              12 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [64, 128)              6 |@@@@@@@@@@@@@@@@@@@@@@@@@@                          |
    [128, 256)             0 |                                                    |
    [256, 512)             1 |@@@@                                                |

    @queue_lat_us[z_wr_iss]:
    [4, 8)                 4 |@@@@                                                |
    [8, 16)               13 |@@@@@@@@@@@@@@@                                     |
    [16, 32)               6 |@@@@@@@                                             |
    [32, 64)               2 |@@                                                  |
    [64, 128)             12 |@@@@@@@@@@@@@@                                      |
    [128, 256)            15 |@@@@@@@@@@@@@@@@@@                                  |
    [256, 512)            33 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@             |
    [512, 1K)             27 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@                    |
    [1K, 2K)               7 |@@@@@@@@                                            |
    [2K, 4K)              14 |@@@@@@@@@@@@@@@@                                    |
    [4K, 8K)              14 |@@@@@@@@@@@@@@@@                                    |
    [8K, 16K)             23 |@@@@@@@@@@@@@@@@@@@@@@@@@@@                         |
    [16K, 32K)            43 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|

    @queue_lat_us[z_wr_int]:
    [2, 4)                10 |@@@@@                                               |
    [4, 8)                71 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@           |
    [8, 16)               88 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
    [16, 32)              50 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@                       |
    [32, 64)              65 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@              |
    [64, 128)             43 |@@@@@@@@@@@@@@@@@@@@@@@@@                           |
    [128, 256)            19 |@@@@@@@@@@@                                         |
    [256, 512)             3 |@                                                   |
    [512, 1K)              1 |                                                    |

Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Prakash Surya <prakash.surya@delphix.com>
Closes #9525
2019-11-01 13:14:54 -07:00