large_page_alloc-win.h

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/** @file include/detail/ut/large_page_alloc-win.h
 Windows-specific implementation bits and pieces for large (huge) page
 allocations. */
 
#ifndef detail_ut_large_page_alloc_win_h
#define detail_ut_large_page_alloc_win_h
 
#include <windows.h>
// _must_ go after windows.h, this comment makes clang-format to preserve
// the include order
#include <memoryapi.h>
 
#include "mysqld_error.h"
#include "storage/innobase/include/detail/ut/helper.h"
#include "storage/innobase/include/ut0log.h"
 
extern const size_t large_page_default_size;
 
namespace ut {
namespace detail {
 
/** Allocates memory backed by large (huge) pages.
 
    @param[in] n_bytes Size of storage (in bytes) requested to be allocated.
    @return Pointer to the allocated storage. nullptr if allocation failed.
*/
inline void *large_page_aligned_alloc(size_t n_bytes) {
  // VirtualAlloc requires for n_bytes to be a multiple of large-page size
  size_t n_bytes_rounded = pow2_round(n_bytes + (large_page_default_size - 1),
                                      large_page_default_size);
  void *ptr =
      VirtualAlloc(nullptr, n_bytes_rounded,
                   MEM_COMMIT | MEM_RESERVE | MEM_LARGE_PAGES, PAGE_READWRITE);
  if (unlikely(!ptr)) {
    ib::log_warn(ER_IB_MSG_856)
        << "large_page_aligned_alloc VirtualAlloc(" << n_bytes_rounded
        << " bytes) failed; Windows error " << GetLastError();
  }
  return ptr;
}
 
/** Releases memory backed by large (huge) pages.
 
    @param[in] ptr Pointer to large (huge) page aligned storage.
    @param[in] n_bytes Size of the storage.
    @return Returns true if releasing the large (huge) page succeeded.
 */
inline bool large_page_aligned_free(void *ptr, size_t n_bytes) {
  if (unlikely(!ptr)) return false;
  auto ret = VirtualFree(ptr, 0, MEM_RELEASE);
  (void)n_bytes;
  if (unlikely(ret == 0)) {
    ib::log_error(ER_IB_MSG_858)
        << "large_page_aligned_free VirtualFree(" << ptr
        << ")  failed;"
           " Windows error "
        << GetLastError();
  }
  return ret != 0;
}
 
/** Queries the current size of large (huge) pages on running system.
 
    @return Large (huge) page size in bytes.
*/
inline size_t large_page_size() { return GetLargePageMinimum(); }
 
}  // namespace detail
}  // namespace ut
 
#endif