diff options
Diffstat (limited to 'compiler-rt/lib/xray/xray_buffer_queue.cc')
| -rw-r--r-- | compiler-rt/lib/xray/xray_buffer_queue.cc | 21 |
1 files changed, 1 insertions, 20 deletions
diff --git a/compiler-rt/lib/xray/xray_buffer_queue.cc b/compiler-rt/lib/xray/xray_buffer_queue.cc index 3ce72890078..5bdd9148d54 100644 --- a/compiler-rt/lib/xray/xray_buffer_queue.cc +++ b/compiler-rt/lib/xray/xray_buffer_queue.cc @@ -19,33 +19,14 @@ #include <memory> #include <sys/mman.h> -#ifndef MAP_NORESERVE -// no-op on NetBSD (at least), unsupported flag on FreeBSD -#define MAP_NORESERVE 0 -#endif - using namespace __xray; using namespace __sanitizer; template <class T> static T *allocRaw(size_t N) { // TODO: Report errors? - // We use MAP_NORESERVE on platforms where it's supported to ensure that the - // pages we're allocating for XRay never end up in pages that can be swapped - // in/out. We're doing this because for FDR mode, we want to ensure that - // writes to the buffers stay resident in memory to prevent XRay itself from - // causing swapping/thrashing. - // - // In the case when XRay pages cannot be swapped in/out or there's not enough - // RAM to back these pages, we're willing to cause a segmentation fault - // instead of introducing latency in the measurement. We assume here that - // there are enough pages that are swappable in/out outside of the buffers - // being used by FDR mode (which are bounded and configurable anyway) to allow - // us to keep using always-resident memory. - // - // TODO: Make this configurable? void *A = reinterpret_cast<void *>( internal_mmap(NULL, N * sizeof(T), PROT_WRITE | PROT_READ, - MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0)); + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)); return (A == MAP_FAILED) ? nullptr : reinterpret_cast<T *>(A); } |
