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-rw-r--r--rts/posix/OSMem.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/rts/posix/OSMem.c b/rts/posix/OSMem.c
index 5291745d53..beffedaac4 100644
--- 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");
}