ghc runtime by default (otherwise depending on a "configure" option) does memory allocation on their own by first mmapping a 1 TB range of memory into the process and then parceling out chunks from it. If one of the chunks is not needed, the kernel needs to be informed - otherwise the system would quickly run out of available RAM. ghc does that via madvise(2). There are two options when doing this informing: MADV_FREE - Means "I don't need this range or the data in it any more". Kernel promises to fail later accesses to it. MADV_DONTNEED - Means "I don't need this range right now - and I don't need the data in it anymore". Kernel promises to make later accesses to it succeed (if necessary by providing a new page initialized with zeroes). MADV_FREE was introduced in Linux 4.5. glibc 2.25 and later always define MADV_FREE. Unpatched ghc 8.0.2 will use either MADV_FREE or MADV_DONTNEED, determined at ghc compile time. Which of them will actually succeed is determined by the Linux kernel at run time. This patch makes ghc try MADV_FREE. If it doesn't work, it falls back to MADV_DONTNEED. The end result is that ghc programs free their memory with Linux < 4.5 again. See https://git.haskell.org/ghc.git/commitdiff/6576bf83cdf4eac05eb88a24aa934a736c91e3da for more information. --- a/rts/posix/OSMem.c +++ b/rts/posix/OSMem.c @@ -541,11 +541,24 @@ void osDecommitMemory(void *at, W_ size) #ifdef MADV_FREE // Try MADV_FREE first, FreeBSD has both and MADV_DONTNEED - // just swaps memory out + // just swaps memory out. Linux >= 4.5 has both DONTNEED and FREE; either + // will work as they both allow the system to free anonymous pages. + // It is important that we try both methods as the kernel which we were + // built on may differ from the kernel we are now running on. r = madvise(at, size, MADV_FREE); -#else - r = madvise(at, size, MADV_DONTNEED); + if(r < 0) { + if (errno == EINVAL) { + // Perhaps the system doesn't support MADV_FREE; fall-through and + // try MADV_DONTNEED. + } else { + sysErrorBelch("unable to decommit memory"); + } + } else { + return; + } #endif + + r = madvise(at, size, MADV_DONTNEED); if(r < 0) sysErrorBelch("unable to decommit memory"); } 694cf7b29d418119c3ed0223973d59'>libedit.scm
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2019-10-30gnu: libedit: Download over HTTPS....* gnu/packages/libedit.scm (libedit)[source]: Use HTTPS. Tobias Geerinckx-Rice
2019-10-30gnu: libedit: Update to 20191025-3.1....* gnu/packages/libedit.scm (libedit): Update to 20191025-3.1. Tobias Geerinckx-Rice
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2019-02-26gnu: libedit: Update to 20181209-3.1....* gnu/packages/libedit.scm: (libedit): Update to 20181209-3.1. Gábor Boskovits