#9706: New block-structured heap organization for 64-bit -------------------------------------+------------------------------------- Reporter: ezyang | Owner: simonmar Type: task | Status: new Priority: normal | Milestone: Component: Runtime | Version: 7.8.3 System | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by rwbarton): I did my experiments on a Linux system with overcommit disabled and watched the `Committed_AS` number from `/proc/meminfo`. According to my tests, anonymous pages which have never been mapped with `PROT_WRITE` don't count against the commit limit. Once a page is given `PROT_WRITE` permissions then it counts as committed even if `PROT_WRITE` is removed before the page is ever touched. I would guess we can "un-commit" pages by doing a new mmap over them with `PROT_NONE`, but I didn't test this. Carter tested that on OS X, mmapping 100 TB doesn't take any noticeable time, at least. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9706#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler