[GHC] #12865: POSIX osDecommitMemory has nasty compatibility problems
#12865: POSIX osDecommitMemory has nasty compatibility problems ----------------------------------------+--------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Runtime System | Version: 8.0.1 Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- `osDecommitMemory` in `rts/posix/OSMem.c` currently does the following, {{{#!c #ifdef MADV_FREE // Try MADV_FREE first, FreeBSD has both and MADV_DONTNEED // just swaps memory out r = madvise(at, size, MADV_FREE); #else r = madvise(at, size, MADV_DONTNEED); #endif if(r < 0) sysErrorBelch("unable to decommit memory"); }}} As it turns out, the Linux kernel as of 4.5 supports `MADV_FREE`. This means that binary distributions built in such environments will use `MADV_FREE`, even if running on an older kernel that does not support this advice. Ultimately this means that any attempt to decommit will fail. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12865 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12865: POSIX osDecommitMemory has nasty compatibility problems -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Runtime System | Version: 8.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): One approach to fixing this would be to instead do something like this, {{{#!c int r = 1; #ifdef MADV_FREE // Try MADV_FREE first, FreeBSD has both and MADV_DONTNEED // just swaps memory out r = madvise(at, size, MADV_FREE); #endif #ifdef MADV_DONTNEED if (r != 0) r = madvise(at, size, MADV_DONTNEED); #endif if(r < 0) sysErrorBelch("unable to decommit memory"); }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12865#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12865: POSIX osDecommitMemory has nasty compatibility problems -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: patch Priority: high | Milestone: 8.2.1 Component: Runtime System | Version: 8.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2780 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => patch * differential: => Phab:D2780 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12865#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#12865: POSIX osDecommitMemory has nasty compatibility problems
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Reporter: bgamari | Owner:
Type: bug | Status: patch
Priority: high | Milestone: 8.2.1
Component: Runtime System | Version: 8.0.1
Resolution: | Keywords:
Operating System: Linux | Architecture:
| Unknown/Multiple
Type of failure: None/Unknown | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s): Phab:D2780
Wiki Page: |
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Comment (by Ben Gamari
#12865: POSIX osDecommitMemory has nasty compatibility problems -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: closed Priority: high | Milestone: 8.2.1 Component: Runtime System | Version: 8.0.1 Resolution: fixed | Keywords: Operating System: Linux | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2780 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: patch => closed * resolution: => fixed -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12865#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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