Class faabric::util::UffdDirtyTracker

class UffdDirtyTracker : public faabric::util::DirtyTracker

Dirty tracking implementation using userfaultfd to write-protect pages, then handle the resulting userspace events when they are written to.

The dirty tracking mode can be one of four options:

• uffd - uses the SIGBUS handler to catch events triggered by accessing missing pages in demand-zero paged memory.

• uffd-wp - same as uffd but adds write-protected events to catch subsequent writes to write-protected pages.

• uffd-thread - same as uffd, but using a background event thread to handle events. This has the benefit of distinguishing between read and write missing page events.

• uffd-thread-wp - same as uffd-thread, but adds write-protected events.

See the docs for more info on these different approaches: https://www.kernel.org/doc/html/latest/admin-guide/mm/userfaultfd.html

Public Functions

UffdDirtyTracker(const std::string &modeIn)

~UffdDirtyTracker()

virtual void clearAll() override

inline virtual std::string getType() override

virtual void startTracking(std::span<uint8_t> region) override

virtual void stopTracking(std::span<uint8_t> region) override

virtual std::vector<char> getDirtyPages(std::span<uint8_t> region) override

virtual void startThreadLocalTracking(std::span<uint8_t> region) override

virtual void stopThreadLocalTracking(std::span<uint8_t> region) override

virtual std::vector<char> getThreadLocalDirtyPages(std::span<uint8_t> region) override

virtual std::vector<char> getBothDirtyPages(std::span<uint8_t> region) override

Public Static Functions

static void sigbusHandler(int sig, siginfo_t *info, void *ucontext) noexcept