Add madvise(buf, len, MADV_HUGEPAGE) call to signal that you strongly prefer huge pages.

This will make a difference if /sys/kernel/mm/transparent_hugepage/enabled has been set to [madvise], and not [always].

2 files changed, 6 insertions, 0 deletions

diff --git a/vespamalloc/src/vespamalloc/malloc/mmappool.cpp b/vespamalloc/src/vespamalloc/malloc/mmappool.cpp
index eadd5aee337..1fb6aa74af9 100644
--- a/vespamalloc/src/vespamalloc/malloc/mmappool.cpp
+++ b/vespamalloc/src/vespamalloc/malloc/mmappool.cpp
@@ -64,6 +64,9 @@ MMapPool::mmap(size_t sz) {
             }
         }
 #ifdef __linux__
+        if (madvise(buf, sz, MADV_HUGEPAGE) != 0) {
+            // Just an advise, not everyone will listen...
+        }
         if (sz >= _G_bigBlockLimit) {
             if (madvise(buf, sz, MADV_DONTDUMP) != 0) {
                 std::error_code ec(errno, std::system_category());
diff --git a/vespamalloc/src/vespamalloc/util/osmem.cpp b/vespamalloc/src/vespamalloc/util/osmem.cpp
index e0cfbc36938..2cb0eb78ad2 100644
--- a/vespamalloc/src/vespamalloc/util/osmem.cpp
+++ b/vespamalloc/src/vespamalloc/util/osmem.cpp
@@ -214,6 +214,9 @@ MmapMemory::getBasePages(size_t len, int mmapOpt, int fd, size_t offset)
         ok = (mem == wanted);
     }
     if (mem != MAP_FAILED) {
+        if (madvise(mem, len, MADV_HUGEPAGE) != 0) {
+            // Just an advise, not everyone will listen...
+        }
         if (getStart() == nullptr) {
             setStart(mem);
             // assumes len parameter is always multiple of the current block size.