On Mon, 14 Oct 2013 22:17:50 +0200 Peter Bex <peter....@xs4all.nl> wrote:
> On Sun, Oct 13, 2013 at 01:51:01PM +0200, Peter Bex wrote: >> After adding these checks, I noticed that in a DEBUGBUILD, the >> hash-table tests started failing consistently with the dreaded >> "out of memory - heap full while resizing" error. After spending the >> weekend groveling through the garbage collector, I finally found a >> very strange statement in runtime.c: after carefully calculating >> the new heap size and ensuring it will fit both the current heap >> and the stack, the heap size is HALVED, for no apparent reason! >> There isn't even a comment stating why this is done. > > I went and asked our tribal elder, and he explained to me that the > rereclaim function's size calculation is based on the FULL heap size, > which consists of two halves: fromspace and tospace. > > This means that the fix of removing the line that divided the > size by two would effectively cause the heap to grow by 200% instead > of 100% in the usual case. This also suggests the correct fix: to > change the code that ensures the heap is at least its current size plus > enough room to accommodate what's on the stack such that it will add > twice the stack size (because it will be tacked onto both the tospace > and the fromspace). > > So here's the three patches again, with some additional comments in the > GC for total clarity, so we will never get confused about this again! Thanks a lot, Peter. I've pushed your patches. Best wishes. Mario -- http://parenteses.org/mario _______________________________________________ Chicken-hackers mailing list Chicken-hackers@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-hackers
