#8199: Get rid of HEAP_ALLOCED -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: feature request | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.7 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: 5435 | Blocking: Related Tickets: | Differential Revisions: D207 -------------------------------------+------------------------------------- Comment (by ezyang): Reproducing some comments from the Phabricator diff for posterity. #9706 didn't work on Windows because Windows counted page table memory as part of committed memory. Go has the same problem: {{{ // Number of bits in page to span calculations (4k pages). // On Windows 64-bit we limit the arena to 32GB or 35 bits. // Windows counts memory used by page table into committed memory // of the process, so we can't reserve too much memory. // See https://golang.org/issue/5402 and https://golang.org/issue/5236. // On other 64-bit platforms, we limit the arena to 512GB, or 39 bits. // On 32-bit, we don't bother limiting anything, so we use the full 32-bit address. // On Darwin/arm64, we cannot reserve more than ~5GB of virtual memory, // but as most devices have less than 4GB of physical memory anyway, we // try to be conservative here, and only ask for a 2GB heap. }}} The links are good reading: https://golang.org/issue/5402 and https://golang.org/issue/5236 (scroll down). Note that there is a little bit about Go relying on overcommitting causing problems for people on systems that don't overcommit; this is not relevant to us since we're not actually committing memory and relying on the OS to lazily initialize it if they don't actually use it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8199#comment:51 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler