[RTEMS Project] #3582: Remove dedicated support for boundary constraint in heap allocator
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trac at rtems.org
Wed Nov 7 11:02:37 UTC 2018
#3582: Remove dedicated support for boundary constraint in heap allocator
------------------------------+-----------------------------
Reporter: Sebastian Huber | Owner: Sebastian Huber
Type: task | Status: assigned
Priority: normal | Milestone: 5.1
Component: score | Version: 5
Severity: normal | Keywords:
Blocked By: | Blocking:
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Some time ago a dedicated support for a boundary constraint was added to
the first fit heap allocator. The use case for this is the libbsd (new
network stack) which needs this for the bus space allocator:
https://www.freebsd.org/cgi/man.cgi?query=bus_dma
It turned out that this feature is rarely used. It makes the first fit
heap allocator implementation considerably more complex. It is also not a
standard allocator feature which makes it more difficult to replace the
first fit heap allocator with something else, e.g. TLSF.
The boundary constraint can be also satisfied by an allocator which
supports only the alignment constraint via:
{{{
if (boundary > alignment) {
assert(alignment == 0 || boundary % alignment == 0);
alignment = boundary;
}
}}}
--
Ticket URL: <http://devel.rtems.org/ticket/3582>
RTEMS Project <http://www.rtems.org/>
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