Using MADV_FREE in jl_gc_free_page(), with fallback to MADV_DONTNEED. (…

…#46362) Co-authored-by: Keno Fischer <keno@alumni.harvard.edu>
JuliaLang · Aug 16, 2022 · ee37ef9 · ee37ef9 · nanosoldier · Aug 16, 2022
1 parent ec98087
commit ee37ef9
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/src/gc-pages.c b/src/gc-pages.c
@@ -302,6 +302,17 @@ void jl_gc_free_page(void *p) JL_NOTSAFEPOINT
     }
 #ifdef _OS_WINDOWS_
     VirtualFree(p, decommit_size, MEM_DECOMMIT);
+#elif defined(MADV_FREE)
+    static int supports_madv_free = 1;
+    if (supports_madv_free) {
+        if (madvise(p, decommit_size, MADV_FREE) == -1) {
+            assert(errno == EINVAL);
+            supports_madv_free = 0;
+        }
+    }
+    if (!supports_madv_free) {
+        madvise(p, decommit_size, MADV_DONTNEED);
+    }
 #else
     madvise(p, decommit_size, MADV_DONTNEED);
 #endif