freebsd-skq

History

John Baldwin f3215338ef Refactor the AIO subsystem to permit file-type-specific handling and improve cancellation robustness. Introduce a new file operation, fo_aio_queue, which is responsible for queueing and completing an asynchronous I/O request for a given file. The AIO subystem now exports library of routines to manipulate AIO requests as well as the ability to run a handler function in the "default" pool of AIO daemons to service a request. A default implementation for file types which do not include an fo_aio_queue method queues requests to the "default" pool invoking the fo_read or fo_write methods as before. The AIO subsystem permits file types to install a private "cancel" routine when a request is queued to permit safe dequeueing and cleanup of cancelled requests. Sockets now use their own pool of AIO daemons and service per-socket requests in FIFO order. Socket requests will not block indefinitely permitting timely cancellation of all requests. Due to the now-tight coupling of the AIO subsystem with file types, the AIO subsystem is now a standard part of all kernels. The VFS_AIO kernel option and aio.ko module are gone. Many file types may block indefinitely in their fo_read or fo_write callbacks resulting in a hung AIO daemon. This can result in hung user processes (when processes attempt to cancel all outstanding requests during exit) or a hung system. To protect against this, AIO requests are only permitted for known "safe" files by default. AIO requests for all file types can be enabled by setting the new vfs.aio.enable_usafe sysctl to a non-zero value. The AIO tests have been updated to skip operations on unsafe file types if the sysctl is zero. Currently, AIO requests on sockets and raw disks are considered safe and are enabled by default. aio_mlock() is also enabled by default. Reviewed by: cem, jilles Discussed with: kib (earlier version) Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D5289		2016-03-01 18:12:14 +00:00
..
etc	Refactor the test/ Makefiles after recent changes to bsd.test.mk (r289158) and	2015-10-12 08:16:03 +00:00
freebsd_test_suite	Add ATF_REQUIRE_FEATURE and PLAIN_REQUIRE_FEATURE macros for	2015-12-16 05:44:53 +00:00
sys	Refactor the AIO subsystem to permit file-type-specific handling and	2016-03-01 18:12:14 +00:00
Kyuafile
Makefile	Copy README into /usr/tests	2015-11-20 03:24:04 +00:00
README	Copy README into /usr/tests	2015-11-20 03:24:04 +00:00

README

src/tests: The FreeBSD test suite
=================================

To run the FreeBSD test suite:
(1)  Make sure that kyua is installed:
       pkg install kyua
(2)  To run the tests:
       kyua test -k /usr/tests/Kyuafile
(3)  To see the test results:
       kyua report  

For further information on using the test suite, read tests(7):
       man tests

Description of FreeBSD test suite
=================================
The build of the test suite is organized in the following manner:

* The build of all test artifacts is protected by the MK_TESTS knob.
  The user can disable these with the WITHOUT_TESTS setting in
  src.conf(5).

* The goal for /usr/tests/ (the installed test programs) is to follow
  the same hierarchy as /usr/src/ wherever possible, which in turn drives
  several of the design decisions described below.  This simplifies the
  discoverability of tests.  We want a mapping such as:

    /usr/src/bin/cp/      -> /usr/tests/bin/cp/
    /usr/src/lib/libc/    -> /usr/tests/lib/libc/
    /usr/src/usr.bin/cut/ -> /usr/tests/usr.bin/cut/
    ... and many more ...

* Test programs for specific utilities and libraries are located next
  to the source code of such programs.  For example, the tests for the
  src/lib/libcrypt/ library live in src/lib/libcrypt/tests/.  The tests/
  subdirectory is optional and should, in general, be avoided.

* The src/tests/ hierarchy (this directory) provides generic test
  infrastructure and glue code to join all test programs together into
  a single test suite definition.

* The src/tests/ hierarchy also includes cross-functional test programs:
  i.e. test programs that cover more than a single utility or library
  and thus don't fit anywhere else in the tree.  Consider this to follow
  the same rationale as src/share/man/: this directory contains generic
  manual pages while the manual pages that are specific to individual
  tools or libraries live next to the source code.

In order to keep the src/tests/ hierarchy decoupled from the actual test
programs being installed --which is a worthy goal because it simplifies
the addition of new test programs and simplifies the maintenance of the
tree-- the top-level Kyuafile does not know which subdirectories may
exist upfront.  Instead, such Kyuafile automatically detects, at
run-time, which */Kyuafile files exist and uses those directly.

Similarly, every directory in src/ that wants to install a Kyuafile to
just recurse into other subdirectories reuses this Kyuafile with
auto-discovery features.  As an example, take a look at src/lib/tests/
whose sole purpose is to install a Kyuafile into /usr/tests/lib/.
The goal in this specific case is for /usr/tests/lib/ to be generated
entirely from src/lib/.

-- 
$FreeBSD$