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108 Commits

Author SHA1 Message Date
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
Prakash Surya e5d1c27e30 Enable use of DTRACE_PROBE* macros in "spl" module
This change modifies some of the infrastructure for enabling the use of
the DTRACE_PROBE* macros, such that we can use tehm in the "spl" module.

Currently, when the DTRACE_PROBE* macros are used, they get expanded to
create new functions, and these dynamically generated functions become
part of the "zfs" module.

Since the "spl" module does not depend on the "zfs" module, the use of
DTRACE_PROBE* in the "spl" module would result in undefined symbols
being used in the "spl" module. Specifically, DTRACE_PROBE* would turn
into a function call, and the function being called would be a symbol
only contained in the "zfs" module; which results in a linker and/or
runtime error.

Thus, this change adds the necessary logic to the "spl" module, to
mirror the tracing functionality available to the "zfs" module. After
this change, we'll have a "trace_zfs.h" header file which defines the
probes available only to the "zfs" module, and a "trace_spl.h" header
file which defines the probes available only to the "spl" module.

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 13:13:43 -07:00
Matthew Macy 4a2ed90013 Wrap Linux module macros
MODULE_VERSION is already defined on FreeBSD. Wrap all of the
used MODULE_* macros for the sake of consistency and portability.

Add a user space noop version to reduce the need for _KERNEL ifdefs.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9542
2019-11-01 10:41:03 -07:00
Brian Behlendorf 10fa254539
Linux 4.14, 4.19, 5.0+ compat: SIMD save/restore
Contrary to initial testing we cannot rely on these kernels to
invalidate the per-cpu FPU state and restore the FPU registers.
Nor can we guarantee that the kernel won't modify the FPU state
which we saved in the task struck.

Therefore, the kfpu_begin() and kfpu_end() functions have been
updated to save and restore the FPU state using our own dedicated
per-cpu FPU state variables.

This has the additional advantage of allowing us to use the FPU
again in user threads.  So we remove the code which was added to
use task queues to ensure some functions ran in kernel threads.

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #9346
Closes #9403
2019-10-24 10:17:33 -07:00
Serapheim Dimitropoulos 851eda3566 Update skc_obj_alloc for spl kmem caches that are backed by Linux
Currently, for certain sizes and classes of allocations we use
SPL caches that are backed by caches in the Linux Slab allocator
to reduce fragmentation and increase utilization of memory. The
way things are implemented for these caches as of now though is
that we don't keep any statistics of the allocations that we
make from these caches.

This patch enables the tracking of allocated objects in those
SPL caches by making the trade-off of grabbing the cache lock
at every object allocation and free to update the respective
counter.

Additionally, this patch makes those caches visible in the
/proc/spl/kmem/slab special file.

As a side note, enabling the specific counter for those caches
enables SDB to create a more user-friendly interface than
/proc/spl/kmem/slab that can also cross-reference data from
slabinfo. Here is for example the output of one of those
caches in SDB that outputs the name of the underlying Linux
cache, the memory of SPL objects allocated in that cache,
and the percentage of those objects compared to all the
objects in it:
```
> spl_kmem_caches | filter obj.skc_name == "zio_buf_512" | pp
name        ...            source total_memory util
----------- ... ----------------- ------------ ----
zio_buf_512 ... kmalloc-512[SLUB]       16.9MB    8
```

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #9474
2019-10-18 13:24:28 -04:00
Matthew Macy 6501906280 Add kmem cache accessors
Make the metaslab platform agnostic again by adding
accessor functions which can be implemented by each
platform.

Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9404
2019-10-10 15:45:52 -07:00
Matthew Macy e4f5fa1229 Fix strdup conflict on other platforms
In the FreeBSD kernel the strdup signature is:

```
char	*strdup(const char *__restrict, struct malloc_type *);
```

It's unfortunate that the developers have chosen to change
the signature of libc functions - but it's what I have to
deal with.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9433
2019-10-10 09:47:06 -07:00
Matthew Macy bced7e3aaa OpenZFS restructuring - move platform specific sources
Move platform specific Linux source under module/os/linux/
and update the build system accordingly.  Additional code
restructuring will follow to make the common code fully
portable.
    
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Macy <mmacy@FreeBSD.org>
Closes #9206
2019-09-06 11:26:26 -07:00