[lld] [llvm] [lld][MachO] Follow-up to use madvise() for threaded file page-in. (PR #157917)
John Holdsworth via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 11 09:10:05 PDT 2025
================
@@ -334,29 +338,37 @@ class SerialBackgroundQueue {
// This code forces the page-ins on multiple threads so
// the process is not stalled waiting on disk buffer i/o.
void multiThreadedPageInBackground(DeferredFiles &deferred) {
+ using namespace std::chrono;
static const size_t pageSize = Process::getPageSizeEstimate();
static const size_t largeArchive = 10 * 1024 * 1024;
-#ifndef NDEBUG
- using namespace std::chrono;
- std::atomic_int numDeferedFilesTouched = 0;
static std::atomic_uint64_t totalBytes = 0;
+ std::atomic_int numDeferedFilesAdvised = 0;
auto t0 = high_resolution_clock::now();
-#endif
auto preloadDeferredFile = [&](const DeferredFile &deferredFile) {
const StringRef &buff = deferredFile.buffer.getBuffer();
if (buff.size() > largeArchive)
return;
-#ifndef NDEBUG
+ if (((uintptr_t)buff.data() & (pageSize - 1)))
+ return; // Not mmap()'d (not page aligned).
----------------
johnno1962 wrote:
I settled on the flooring in the finish:
```
auto aligned = llvm::alignAddr(buff.data(), Align(pageSize));
auto rounded = llvm::alignTo(buff.size(), Align(pageSize));
if (madvise((void *)aligned, buff.size(), MADV_WILLNEED) < 0)
https://github.com/llvm/llvm-project/pull/157917
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