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| author | Ian Lance Taylor <ian@gcc.gnu.org> | 2013-02-15 18:55:09 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2013-02-15 18:55:09 +0000 |
| commit | 3ab98a471c4b1aec557583e674beacd15be4955d (patch) | |
| tree | 69367e678dd8ce0bf0495ccdf1a1712913949390 /libgo | |
| parent | 4dddfc74f331653b453b9123ecf3c93a58a9aade (diff) | |
| download | gcc-3ab98a471c4b1aec557583e674beacd15be4955d.zip gcc-3ab98a471c4b1aec557583e674beacd15be4955d.tar.gz gcc-3ab98a471c4b1aec557583e674beacd15be4955d.tar.bz2 | |
runtime: Do not reserve huge amount of swap on 32 bit architectures.
The mmap() call which reserves the arena should have MAP_NORESERVE
flag as in typical cases this memory will never be (fully) needed.
This matters in environments which do not do Linux style memory
overcommit, such as OpenIndiana/OpenSolaris/Solaris.
The MAP_NORESERVE flag does not exist on all operating systems
(for example FreeBSD). Therefore we define it to zero value in
case it does not exist.
Fixes issue 21.
From-SVN: r196088
Diffstat (limited to 'libgo')
| -rw-r--r-- | libgo/runtime/mem.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/libgo/runtime/mem.c b/libgo/runtime/mem.c index e70694c..e606bdd 100644 --- a/libgo/runtime/mem.c +++ b/libgo/runtime/mem.c @@ -18,6 +18,10 @@ #endif #endif +#ifndef MAP_NORESERVE +#define MAP_NORESERVE 0 +#endif + #ifdef USE_DEV_ZERO static int dev_zero = -1; #endif @@ -134,7 +138,11 @@ runtime_SysReserve(void *v, uintptr n) return v; } - p = runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0); + // Use the MAP_NORESERVE mmap() flag here because typically most of + // this reservation will never be used. It does not make sense + // reserve a huge amount of unneeded swap space. This is important on + // systems which do not overcommit memory by default. + p = runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE|MAP_NORESERVE, fd, 0); if(p == MAP_FAILED) return nil; return p; |