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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
