> `jdk.internal.foreign.SegmentFactories::allocateNativeInternal` assumes that > the underlying implementation of malloc aligns allocations on 16 byte > boundaries for 64 bit platforms, and 8 byte boundaries on 32 bit platforms. > So for any allocation where the requested alignment is less than or equal to > this default alignment it makes no adjustment. > > However, this assumption does not hold for all allocators. Specifically > jemallc, used by libc on FreeBSD will align small allocations on 8 or 4 byte > boundaries, respectively. This causes allocateNativeInternal to sometimes > return memory that is not properly aligned when the requested alignment is > exactly 16 bytes. > > To make sure we honour the requested alignment when it exaclty matches the > quantum as defined by MAX_MALLOC_ALIGN, this patch ensures that we adjust the > alignment also in this case. > > This should make no difference for platforms where malloc allready aligns on > the quantum, except for a few unnecessary trivial calculations. > > This work was sponsored by: The FreeBSD Foundation
Harald Eilertsen has updated the pull request incrementally with one additional commit since the last revision: Fix calculation of allocationSize when byteAlignment < MAX_MALLOC_ALIGN This work was sponsored by: The FreeBSD Foundation ------------- Changes: - all: https://git.openjdk.org/jdk/pull/28235/files - new: https://git.openjdk.org/jdk/pull/28235/files/15daa51b..c723058e Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=28235&range=03 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28235&range=02-03 Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/28235.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/28235/head:pull/28235 PR: https://git.openjdk.org/jdk/pull/28235
