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"); } aabfad'>xfce.scm
AgeCommit message (Expand)Author
2017-01-15gnu: xfce4-terminal: Update to 0.8.3....Ricardo Wurmus
2016-06-27gnu: Add orage....Kei Kebreau
2016-05-19Update name for Kei Kebreau....Kei Kebreau
2016-04-26gnu: Add xfce4-taskmanager....Kei Yamashita
2016-04-25gnu: xfce: Add ristretto....宋文武
2016-04-25gnu: Add ristretto....Kei Yamashita
2016-04-14gnu: packages: Use 'search-patches' everywhere....Alex Kost
2016-03-15gnu: xfce: Add xfce4-power-manager....Leo Famulari
2016-03-15gnu: Add xfce4-power-manager....Florian Paul Schmidt
2016-03-02gnu: xfce: Don't wrap 'startxfce4'....宋文武
2016-02-28gnu: libwnck: Rename variable for GTK+ 2 variant....Andreas Enge
2016-02-27gnu: Fix misplaced commas (unquote)....Mark H Weaver
2016-02-23gnu: Add xfce4-xkb-plugin....Andreas Enge
2015-11-29gnu: xfce-session: Enable shutdown/reboot menu entries....Ricardo Wurmus
2015-10-30Merge branch 'master' into dbus-update宋文武
2015-10-30gnu: xfce4-session: Fix xflock4....David Thompson
2015-10-18gnu: xfconf: Fix test....宋文武