diff options
| -rw-r--r-- | runtime/gc/collector/mark_compact.cc | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/runtime/gc/collector/mark_compact.cc b/runtime/gc/collector/mark_compact.cc index 403a382668..d73418b8b3 100644 --- a/runtime/gc/collector/mark_compact.cc +++ b/runtime/gc/collector/mark_compact.cc @@ -61,14 +61,25 @@ namespace art { // We require MREMAP_DONTUNMAP functionality of the mremap syscall, which was -// introduced in 5.13 kernel version. Check for that on host. Checking -// on Android is not required as MREMAP_DONTUNMAP and userfaultfd were enabled -// together. +// introduced in 5.13 kernel version. +static bool HaveMremapDontunmap() { + void* old = mmap(nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0); + CHECK_NE(old, MAP_FAILED); + void* addr = mremap(old, kPageSize, kPageSize, MREMAP_MAYMOVE | MREMAP_DONTUNMAP, nullptr); + CHECK_EQ(munmap(old, kPageSize), 0); + if (addr != MAP_FAILED) { + CHECK_EQ(munmap(addr, kPageSize), 0); + return true; + } else { + return false; + } +} +static bool gHaveMremapDontunmap = IsKernelVersionAtLeast(5, 13) || HaveMremapDontunmap(); + // Concurrent compaction termination logic depends on the kernel having // the fault-retry feature (allowing repeated faults on the same page), which was // introduced in 5.7. On Android this feature is backported on all the kernels where // userfaultfd is enabled. -static const bool gHaveMremapDontunmap = kIsTargetAndroid || IsKernelVersionAtLeast(5, 13); static const bool gKernelHasFaultRetry = kIsTargetAndroid || IsKernelVersionAtLeast(5, 7); #ifndef ART_FORCE_USE_READ_BARRIER |