CircuitPython - a Python implementation for teaching coding with microcontrollers https://git.suspectdevices.com/suspect-devices/circuitpython/atom?h=4.x 2019-02-02T00:05:37+00:00 2019-02-02T00:05:37+00:00 Scott Shawcroft scott@tannewt.org 2019-02-02T00:05:37+00:00 urn:sha1:5555a24479a2f40d52d008c991f191d3b9b566bf It's contents change often and may be referenced elsewhere. Fixes #1443 2018-07-25T18:49:18+00:00 Scott Shawcroft scott@tannewt.org 2018-07-25T18:49:18+00:00 urn:sha1:1ffb0a714f056eaffdebaa411c3fcadb79a2b6d1 2018-07-19T19:19:21+00:00 Dan Halbert halbert@halwitz.org 2018-07-19T19:19:21+00:00 urn:sha1:be1d882a8b5d2878c9b4402ae641abf9a88cd682 2018-07-03T12:45:50+00:00 Scott Shawcroft scott@tannewt.org 2018-06-27T18:17:13+00:00 urn:sha1:252aacdddf1aae89e3ebe91ca72a3ad666728e37 2018-03-25T20:11:30+00:00 Jeff Epler jepler@unpythonic.net 2018-03-25T19:25:04+00:00 urn:sha1:922b7c313197a28aa8243710d2d26f1034575674 This fixes a crash running the cpydiff/core_class_superproperty.py test, but it does not fix the difference to cpython3. Closes: #705 2018-01-24T22:13:26+00:00 Scott Shawcroft scott.shawcroft@gmail.com 2018-01-24T22:13:26+00:00 urn:sha1:aa0ce98b3e7228a469fa11709fbd6864242079b4 2018-01-24T18:33:46+00:00 Scott Shawcroft scott.shawcroft@gmail.com 2018-01-24T00:22:05+00:00 urn:sha1:416abe33ed44e44d8f75342731080217e123278b This adapts the allocation process to start from either end of the heap when searching for free space. The default behavior is identical to the existing behavior where it starts with the lowest block and looks higher. Now it can also look from the highest block and lower depending on the long_lived parameter to gc_alloc. As the heap fills, the two sections may overlap. When they overlap, a collect may be triggered in order to keep the long lived section compact. However, free space is always eligable for each type of allocation. By starting from either of the end of the heap we have ability to separate short lived objects from long lived ones. This separation reduces heap fragmentation because long lived objects are easy to densely pack. Most objects are short lived initially but may be made long lived when they are referenced by a type or module. This involves copying the memory and then letting the collect phase free the old portion. QSTR pools and chunks are always long lived because they are never freed. The reallocation, collection and free processes are largely unchanged. They simply also maintain an index to the highest free block as well as the lowest. These indices are used to speed up the allocation search until the next collect. In practice, this change may slightly slow down import statements with the benefit that memory is much less fragmented afterwards. For example, a test import into a 20k heap that leaves ~6k free previously had the largest continuous free space of ~400 bytes. After this change, the largest continuous free space is over 3400 bytes.