Commit Graph

50 Commits

Author SHA1 Message Date
Krzysztof Chruściński
0bb25d2e17 lib: os: spsc_pbuf: Clarify using cache management in the module
Packet buffer can be used for sharing data between cores. In that
case when any core has data cache then data cache handling must
be enabled in the module. However, it shall never be enabled when
the packet buffer is used on a single core. Adding that information
to the documentation.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
2024-07-01 16:07:30 -04:00
Chris Friedt
487a8756c3 posix: eventfd: fix dependency cycle between net and posix
Until recently, the posix api was purely a consumer of the
network subsystem. However, a dependency cycle was added as
a stop-gap solution for challenges with the native platform.

Specifically,

1. eventfd symbols conflict with those of the host
2. eventfd was excluded from native libc builds via cmake

If any part of the posix were then to select the network
subsystem (which is a legitimate use case, given that networking
is a part of the posix api), we would get a build error due to
the Kconfig dependency cycle.

As usual, with dependency cycles, the cycle can be broken
via a third, mutual dependency.

What is the third mutual dependency? Naturally, it is ZVFS
which was planned some time ago. ZVFS will be where we
collect file-descriptor and FILE-pointer APIs so that we can
ensure consistency for Zephyr users.

This change deprecates EVENTFD_MAX in favour of
ZVFS_EVENTFD_MAX.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>
2024-06-04 16:27:12 -05:00
Chris Friedt
bc4374b5fe posix: deprecate POSIX_MAX_FDS and add POSIX_DEVICE_IO
The POSIX_MAX_FDS option does not correspond to any standard
POSIX option. It was used to define the size of the file
descriptor table, which is by no means exclusively used by
POSIX (also net, fs, ...).

POSIX_MAX_FDS is being deprecated in order to ensure that
Zephyr's POSIX Kconfig variables correspond to those defined in
the specification, as of IEEE 1003.1-2017. Namely,
POSIX_OPEN_MAX. CONFIG_POSIX_MAX_OPEN_FILES is being deprecated
for the same reason.

To mitigate any possible layering violations, that option is
not user selectable. It tracks the newly added
CONFIG_ZVFS_OPEN_MAX option, which is native to Zephyr.

With this deprecation, we introduce the following Kconfig
options that map directly to standard POSIX Option Groups by
simply removing "CONFIG_":

* CONFIG_POSIX_DEVICE_IO

Similarly, with this deprecation, we introduce the following
Kconfig options that map directly to standard POSIX Options by
simply removing "CONFIG":

* CONFIG_POSIX_OPEN_MAX

In order to maintain parity with the current feature set, we
introduce the following Kconfig options.

* CONFIG_POSIX_DEVICE_IO_ALIAS_CLOSE
* CONFIG_POSIX_DEVICE_IO_ALIAS_OPEN
* CONFIG_POSIX_DEVICE_IO_ALIAS_READ
* CONFIG_POSIX_DEVICE_IO_ALIAS_WRITE

Gate open(), close(), read(), and write() via the
CONFIG_POSIX_DEVICE_IO Kconfig option and move
implementations into device_io.c, to be conformant with the
spec.

Lastly, stage function names for upcoming ZVFS work, to be
completed as part of the LTSv3 Roadmap (e.g. zvfs_open(), ..).

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>
2024-06-04 16:27:12 -05:00
Anas Nashif
0b999c0943 lib: move utilities into own folder
Move various utilities out of lib into own folder for better assignement
and management in the maintainer file. lib/os has become another dumping
ground for everything and it the Kconfig and contents in that folder
became difficult to manage, configure and test.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-12-22 09:54:12 +01:00
Anas Nashif
d4c881da04 lib: mem_block: move to own folder
Move mem_block into own folder and seperate from lib/os and heap
configuration.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-12-13 17:27:54 -05:00
Anas Nashif
6cb588820f lib: os: move heap to own folder
consolidate all heap related files and implementation into one folder.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-12-13 17:27:54 -05:00
Flavio Ceolin
15aa3acaf6 kconfig: Remove MP_NUM_CPUS usage
Zephyr's code base uses MP_MAX_NUM_CPUS to
know how many cores exists in the target. It is
also expected that both symbols MP_MAX_NUM_CPUS
and MP_NUM_CPUS have the same value, so lets
just use MP_MAX_NUM_CPUS and simplify it.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2023-10-03 17:45:53 +01:00
Anas Nashif
6d23a960db lib: os: build fdtable conditionally
Stop building fdtable by default, make it conditional and build it only
when needed.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-09-28 06:25:16 -04:00
Anas Nashif
e6885a4515 lib: crc: move from lib/os to lib/crc
Move crc implementation to own directory and reduce clutter in lib/os.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-08-18 08:52:16 +03:00
Anas Nashif
234032cac7 os: disable CRC by default
Users of CRC shall enable the the kconfig and not rely on it being
enabled by default.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2023-08-18 08:52:16 +03:00
Gerard Marull-Paretas
90b247b90b lib: os: add support for system power off
Add a new API to perform an immediate system power off:
`sys_poweroff()`.

Until now, this functionality has been implemented via the system power
management module, but in a clunky fashion. The way system PM works is
by defining some idle states in devicetree, that, given some properties
(e.g. minimal residency, exit latency, etc.) are automatically selected
when system goes to idle based on the expected next wake-up. However,
system off is a power state that one typically wants to control manually
from the application because it implies state loss, and in most cases,
configuring some sort of wake-up source. So in general, it is not
desired to let the system enter this state automatically. This led to
the following stuff in-tree:

from `boards/arm/mimxrt595_evk/mimxrt595_evk_cm33.dts`:

```c
/*
 * Deep power-down mode is supported in this SoC through
 *  'PM_STATE_SOFT_OFF' state. There is no entry for this in device tree,
 *  user can call pm_state_force to enter this state.
 */
```

That is, state not being defined in devicetree so that PM subsystem
doesn't pick it automatically, but still implemented in in the PM hooks:

from `soc/arm/nxp_imx/rt5xx/power.c`, `pm_state_set()`:
```c
case PM_STATE_SOFT_OFF:
	set_deepsleep_pin_config();
	POWER_EnterDeepPowerDown(EXCLUDE_FROM_DEEP_POWERDOWN);
	break;
```

And to actually make use of this state, users had to do this kind of
abominations:

```c
pm_state_force(0u, &(struct pm_state_info){ PM_STATE_SOFT_OFF, 0, 0 });

/* Now we need to go sleep. This will let the idle thread runs and
 * the pm subsystem will use the forced state. To confirm that the
 * forced state is used, lets set the same timeout used previously.
 */
k_sleep(K_SECONDS(SLEEP_S));

printk("ERROR: System off failed\n");
while (true) {
	/* spin to avoid fall-off behavior */
}
```

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
2023-08-04 16:59:36 +02:00
Joshua Lilly
69966dd452 lib: hashmap: Move hash table files lib/hashmap
Moves the hashmap related files into their own directory

Signed-off-by: Joshua Lilly <jgl@fb.com>
2023-03-02 12:03:07 -05:00
Chris Friedt
0bda7b30df lib: os: add hashmap support
* Add a flexible Hashmap API
* Add a Separate-Chaining Hashmap Implementation
* Add a Open-Addressing Linear Probe Hashmap Implementation
* Add a C-Wrapper for `std::unordered_map` for benchmarking

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2023-02-22 19:14:05 +01:00
Chris Friedt
b75df60f0b lib: os: add hash function specification and implementation
Hash functions are necessary for Hashmaps (a.k.a. Hash Tables).

* Create a flexible hash function interface
* Implementation 1. Murmur3
* Implementation 2. djb2
* Kconfig option for system-wide 32-bit hash

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2023-02-22 19:14:05 +01:00
Chris Friedt
2e36d1f3eb lib: os: add CRC shell command for integrity verification
There are several Zephyr shell commands that are used for
transferring data over a possibly unreliable connection such as a
UART into either memory or flash. For example, `flash load` and
`devmem load`.

Make the CRC functions available so that they can be used to
verify the integrity of data transferred over possibly
unreliable connections.

Signed-off-by: Chris Friedt <cfriedt@meta.com>
2022-11-29 09:32:28 +01:00
Anas Nashif
cffe98d9de crc: Make the build of crc function dependent on a Kconfig
Add CONFIG_CRC for building CRC related routines.
CRC routines are now being built for each application, whether used or
not and are add in the build system unconditionally.

Keep CONFIG_CRC enabled by default for now and until all users have
converted to use the new option.

Partial fix for #50654

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2022-11-23 13:30:00 +01:00
Anas Nashif
a5bd666f4e lib: notify: build sys-notify conditionally.
Add a new Kconfig and build this code conditionally, so we do not end up
with this file being built for each zephyr app.

Partial fix for #50654

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2022-10-03 10:18:15 +02:00
Anas Nashif
a81b322828 lib: onoff: add a config for on-off and build conditionally
Do not build this service unconditionally.

Partial fix of #50654

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2022-10-03 10:18:15 +02:00
Enjia Mai
e696de1f31 lib: os: disable PRINTK_SYNC while using EFI console as log backend
There is a spinlock used in the EFI console code for printing
one line string. It already made the log output being in order
under multi-cores, so it doesn't need a printk sync spinlock
again. Disable it while using EFI console as a log backend.

Fixes #47512.

Signed-off-by: Enjia Mai <enjia.mai@intel.com>
2022-08-11 12:17:24 +02:00
Krzysztof Chruscinski
b6dcdb17f9 lib: os: spsc_pbuf: Improve data cache configuration
Use CONFIG_DCACHE_LINE_SIZE to determine distance between
fields modified by different cores.
Add option which specifies what is the data cache line
of the remote core. Maximum from local and remote cache
line sizes is used as distance and alignement.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2022-07-18 12:21:16 -04:00
Krzysztof Chruscinski
715ae32501 lib: os: spsc_pbuf: Add option to get maximum utilization
Add option to track maximum utilization of the packet buffer.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2022-06-30 10:30:49 +02:00
Krzysztof Chruscinski
fa055f743f lib: os: spsc_pbuf: Extend API with zero copy model
Added functions which allow to use zero copy model for handling
data within the packet buffer.

Additionally, added handling of cache by adding option to keep rd_idx
in different cache line than wr_idx and data.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2022-06-30 10:30:49 +02:00
Krzysztof Chruscinski
0829610bbc lib: os: spsc_pbuf: Add option to use cache
Add flags option to init call and a flag to use cache.
Add Kconfig choice to pick how to approach cache. Cache can be
enforced in all spsc_pbuf instances, disable in all, or runtime selected
based on configuration flag. Option is added to allow memory footprint
savings.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2022-06-07 19:04:35 +02:00
Krzysztof Chruscinski
2f189e39a5 lib: os: Rename icmsg_buf to spsc_pbuf
Move icmsg_buf to lib/os and rename to spsc_pbuf (Single Producer
Single Consumer Packet Buffer). It is a generic module and initially
was created as internal module for ipc service.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2022-06-07 19:04:35 +02:00
Gerard Marull-Paretas
95fb0ded6b kconfig: remove Enable from boolean prompts
According to Kconfig guidelines, boolean prompts must not start with
"Enable...". The following command has been used to automate the changes
in this patch:

sed -i "s/bool \"[Ee]nables\? \(\w\)/bool \"\U\1/g" **/Kconfig*

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2022-03-09 15:35:54 +01:00
Andy Ross
528bef2d22 lib/os: Add sys_winstream lockless shared memory byte stream IPC
It's not uncommon to have Zephyr running in environments where it
shares a memory bus with a foreign/non-Zephyr system (both the older
Intel Quark and cAVS audio DSP systems share this property).  In those
circumstances, it would be nice to have a utility that allows an
arbitrary-sized chunk of that memory to be used as a unidirectional
buffered byte stream without requiring complicated driver support.
sys_winstream is one such abstraction.

This code is lockless, it makes no synchronization demands of the OS
or hardware beyond memory ordering[1].  It implements a simple
file/socket-style read/write API.  It produces small code and is high
performance (e.g. a read or write on Xtensa is about 60 cycles plus
one per byte copied).  It's bidirectional, with no internal Zephyr
dependencies (allowing it to be easily ported to the foreign system).
And it's quite a bit simpler (especially for the reader) than the
older cAVS trace protocol it's designed to replace.

[1] Which means that right now it won't work reliably on arm64 until
we add a memory barrier framework to Zephyr!  See notes in the code;
the locations for the barriers are present, but there's no utility to
call.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2022-01-13 14:01:23 -05:00
Daniel Leung
5604b98f21 lib: os: group heap related kconfigs under a menu
This groups the heap related kconfigs under a menu
so they are under a group (!).

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2022-01-11 16:10:53 -05:00
Emil Gydesen
43b827c562 zephyr: Add UTF8 kconfig to conditionally compile utf8.c
Add the kconfig option so that the utf8.c file can be
conditionally compile, and only for the applications
that need it.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>
2022-01-11 11:50:15 +01:00
Daniel Leung
f6e2705719 sys: heap: add support for heap listener
This adds notification in the heap code to emit events for
heap listeners.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2022-01-10 10:28:04 -05:00
Daniel Leung
071db26f6c lib: os: CONFIG_HEAP_LISTENER to be hidden
This changes CONFIG_HEAP_LISTENER to be a hidden kconfig so that
the actual heap implementation can select it to enable
notifications. Each heap implementations will have their own
kconfigs to enable heap listener functionality so that app
can be built to only listen to certain heap implementations.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
2022-01-10 10:28:04 -05:00
Damian Krolik
3aedda9852 lib: os: add heap event listener
* add generic heap event listener module that can be used
  for notifying an application of heap-related events
* use the listener module in newlib libc hooks
* add a unit test

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>
2021-12-18 07:49:15 -05:00
Gerard Marull-Paretas
78dc8ce338 drivers: timer: improve sys_timer_disable usage
- Remove the weak symbol definition
- Notify about the capability of disabling via a selected Kconfig option
  (CONFIG_SYSTEM_TIMER_HAS_DISABLE_SUPPORT)
- Provide a dummy inline function when the functionality is not
  available

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2021-12-04 07:34:53 -05:00
Chen Peng1
a71cd8790f heap: add functions to get heap runtime statistics
add functions to get the sys_heap runtime statistics,
include total free bytes, total allocated bytes.

Signed-off-by: Chen Peng1 <peng1.chen@intel.com>
2021-11-11 16:21:43 -05:00
Nicolas Pitre
46db2b491d lib/os/heap: option for optimizing for one heap size on 32-bit systems
The "small" heap is is way sufficient for most 32-bit systems.

Let's provide the option to have only one type of heap allowing for
smaller and faster heap code due to not having a bunch of runtime
conditionals based on the heap size.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
2021-10-17 07:34:51 -04:00
Carlo Caione
43cb00df08 multi_heap: Introduce shared multi-heap memory pool manager
The shared multi-heap memory pool manager uses the multi-heap allocator
to manage a set of reserved memory regions with different capabilities /
attributes (cacheable, non-cacheable, etc...) defined in the DT.

The user can request allocation from the shared pool specifying the
capability / attribute of interest for the memory (cacheable /
non-cacheable memory, etc...)

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
2021-10-12 07:44:46 -04:00
Kumar Gala
932bc399ba lib: os: Removed deprecated Kconfig PRINTK64 symbol
The symbol have been deprecated for 2 releases so remove the code
associated with it.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
2021-06-11 16:35:19 -05:00
Gerard Marull-Paretas
f163bdb280 power: move reboot functionality to os lib
Reboot functionality has nothing to do with PM, so move it out to the
subsys/os folder.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
2021-04-28 20:34:00 -04:00
Krzysztof Chruscinski
1fd71ca043 lib: os: mpsc_pbuf: Add optional debug features
Added optional debug prints. Logging cannot be used because
mpsc pbuf is used by the logging.

Added option to clear packet memory after allocation. Option is
enabled in Kconfig.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2021-04-19 10:59:23 -04:00
Krzysztof Chruscinski
3a765f4384 lib: os: Add mpsc (multiple producer, single consumer) packet buffer
Added module for storing variable length packets in a ring buffer.
Implementation assumes multiple producing contexts and single consumer.

API provides zero copy functionality with alloc, commit, claim, free
scheme.

Additionally, there are functions optimized for storing single word
packets and packets consisting of a word and a pointer. Buffer can work
in two modes: saturation or overwriting the oldest packets when buffer
has no space to allocate for a new buffer.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2021-04-19 10:59:23 -04:00
Nicolas Pitre
7a91cf0176 Revert "lib/os/heap: introduce option to force big heap mode"
This reverts commit b6b6d39bb6.

With both commit 4690b8d5ec ("libc/minimal: fix malloc() allocated
memory alignment") and commit c822e0abbd ("libc/minimal: fix
realloc() allocated memory alignment") in place, there is no longer
a need for enforcing the big heap mode on every allocations.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
2021-02-19 07:32:22 -05:00
Martin Åberg
b6b6d39bb6 lib/os/heap: introduce option to force big heap mode
This option allows forcing big heap mode. Useful on for getting 8-byte
aligned blocks on 32-bit machines.

Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
2021-01-24 10:11:11 -05:00
Peter Bigot
bb99422c8a lib/os: replace z_vprintk with cbprintf
Using the same implementation as the rest of Zephyr reduces code size.

Update options and expected results for formatting test.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2020-11-13 06:38:01 -05:00
Peter Bigot
33103828dc lib: add cbprintf capability
This commit adds a C99 stdio value formatter capability where
generated text is emitted through a callback.  This allows generation
of arbitrarily long output without a buffer, functionality that is
core to printk, logging, and other system and application needs.

The formatter supports most C99 specifications, excluding:
* %Lf long double conversion
* wide character output

Kconfig options allow disabling features like floating-point
conversion if they are not necessary.  By default most conversions are
enabled.

The original z_vprintk() implementation is adapted to meet the
interface requirements of cbvprintf, and made available as an opt-in
feature for space-constrained applications that do not need full
formatting support.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
2020-11-13 06:38:01 -05:00
Nicolas Pitre
6014e5f441 lib/os/heap: remove big_heap restriction for aligned allocations
After commit 8a6b02b5bf ("lib/os/heap: some code simplification in
sys_heap_aligned_alloc()") it is no longer required to have a "big"
heap for aligned allocations to work on 32-bit targets. While the
natural alignment for returned memory has an offset of 4 within a chunk
unit due to the smaller header size, returning to a chunkid from a
memory pointer with an offset of 8 will fall back onto the proper chunk
number once the 4 is substracted and then divided by 8.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
2020-07-14 19:35:52 -04:00
Andy Ross
3f9ad86b1d kernel/printk: Make it synchronous
Currently printk isn't synchronized except at the byte output level,
leading to interleaving of messages on SMP systems that try to log
simultaneously.  This is actually fairly amusing, and actually helpful
occasionally to validate inter-CPU contention down to the "few cycles"
level.

Still, when you're printing data you need to read, you need to be able
to read it.  Put a spinlock around each buffered line.  This has to
happen in a few places, as there are three different code paths taken
for !USERSPACE, syscall, and user mode.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2020-06-27 08:14:58 -04:00
Andy Ross
973487fdad lib/os: Rework/shrink printk conversions, add 64 bit support
Add support for 64 bit conversions in a uniformly expressable way by
printing values backwards into a buffer on the stack first.  This
allows all operations to work on the low bits of the value and so the
code doesn't need to care (beyond the size of that buffer) about the
word size.  This trick also doesn't care about the specifics of the
base value, so in the process this unifies the decimal and hex printk
conversion code to a single function.

This comes at a mild cost in CPU cycles to the decimal converter and
somewhat higher cost to hex (because it's now doing a full div/mod
operation instead of shifting and masking).  And stack usage has grown
by a few words to hold the temporary.  But the benefits in code size
are substantial (e.g. ~250 bytes of .text on arm32).

Note that this also contains a change to tests/kernel/common to
address what appears to have been a bug in the original converters.
The printk test uses a format string that looks like "%-4x%-2p" and
feeds it the literal arguments "0xABCDEF" and "(char *)42".
Now... clearly both those results are going to overflow the 4 and
2-byte field sizes, so there shouldn't be any whitespace between these
fields.  But the test was written to expect two spaces, inexplicably
(yes, I checked: POSIX-compatible printf implementations don't have
those spaces either).

The new code is definitely doing the right thing, so fix the test
instead.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2020-06-24 13:43:40 -07:00
Andy Ross
ed258e9c6f lib/os/heap: Add sys_heap_aligned_alloc()
Add support for a C11-style aligned_alloc() in the heap
implementation.  This is properly optimized, in the sense that unused
prefix/suffix data around the chosen allocation is returned to the
heap and made available for general allocation.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2020-06-22 14:54:04 -04:00
Andy Ross
aa4227754c lib/os: Add sys_heap, a new/simpler/faster memory allocator
The existing mem_pool implementation has been an endless source of
frustration.  It's had alignment bugs, it's had racy behavior.  It's
never been particularly fast.  It's outrageously complicated to
configure statically.  And while its fragmentation resistance and
overhead on small blocks is good, it's space efficiencey has always
been very poor due to the four-way buddy scheme.

This patch introduces sys_heap.  It's a more or less conventional
segregated fit allocator with power-of-two buckets.  It doesn't expose
its level structure to the user at all, simply taking an arbitrarily
aligned pointer to memory.  It stores all metadata inside the heap
region.  It allocates and frees by simple pointer and not block ID.
Static initialization is trivial, and runtime initialization is only a
few cycles to format and add one block to a list header.

It has excellent space efficiency.  Chunks can be split arbitrarily in
8 byte units.  Overhead is only four bytes per allocated chunk (eight
bytes for heaps >256kb or on 64 bit systems), plus a log2-sized array
of 2-word bucket headers.  No coarse alignment restrictions on blocks,
they can be split and merged (in units of 8 bytes) arbitrarily.

It has good fragmentation resistance.  Freed blocks are always
immediately merged with adjacent free blocks.  Allocations are
attempted from a sample of the smallest bucket that might fit, falling
back rapidly to the smallest block guaranteed to fit.  Split memory
remaining in the chunk is always returned immediately to the heap for
other allocation.

It has excellent performance with firmly bounded runtime.  All
operations are constant time (though there is a search of the smallest
bucket that has a compile-time-configurable upper bound, setting this
to extreme values results in an effectively linear search of the
list), objectively fast (about a hundred instructions) and amenable to
locked operation.  No more need for fragile lock relaxation trickery.

It also contains an extensive validation and stress test framework,
something that was sorely lacking in the previous implementation.

Note that sys_heap is not a compatible API with sys_mem_pool and
k_mem_pool.  Partial wrappers for those (now-) legacy APIs will appear
later and a deprecation strategy needs to be chosen.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2020-04-14 10:05:55 -07:00
Ulf Magnusson
bd6e04411e kconfig: Clean up header comments and make them consistent
Use this short header style in all Kconfig files:

    # <description>

    # <copyright>
    # <license>

    ...

Also change all <description>s from

    # Kconfig[.extension] - Foo-related options

to just

    # Foo-related options

It's clear enough that it's about Kconfig.

The <description> cleanup was done with this command, along with some
manual cleanup (big letter at the start, etc.)

    git ls-files '*Kconfig*' | \
        xargs sed -i -E '1 s/#\s*Kconfig[\w.-]*\s*-\s*/# /'

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
2019-11-04 17:31:27 -05:00
Anas Nashif
db92e5c66e lib: flatten all loose components into one lib
lib/ was starting to get messy and inconsitent. Files being either
dumped in the root or in sub-directories without a clear plan.
Move all library components into one single folder and call it 'os'.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2019-01-22 07:45:22 -05:00