support: Add LockedPool

Add a pool for locked memory chunks, replacing LockedPageManager.

This is something I've been wanting to do for a long time. The current
approach of locking objects where they happen to be on the stack or heap
in-place causes a lot of mlock/munlock system call overhead, slowing
down any handling of keys.

Also locked memory is a limited resource on many operating systems (and
using a lot of it bogs down the system), so the previous approach of
locking every page that may contain any key information (but also other
information) is wasteful.

1 files changed, 0 insertions, 70 deletions

diff --git a/src/support/pagelocker.cpp b/src/support/pagelocker.cpp
deleted file mode 100644
index 7cea2d88c5..0000000000
--- a/src/support/pagelocker.cpp
+++ /dev/null
@@ -1,70 +0,0 @@
-// Copyright (c) 2009-2015 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include "support/pagelocker.h"
-
-#if defined(HAVE_CONFIG_H)
-#include "config/bitcoin-config.h"
-#endif
-
-#ifdef WIN32
-#ifdef _WIN32_WINNT
-#undef _WIN32_WINNT
-#endif
-#define _WIN32_WINNT 0x0501
-#define WIN32_LEAN_AND_MEAN 1
-#ifndef NOMINMAX
-#define NOMINMAX
-#endif
-#include <windows.h>
-// This is used to attempt to keep keying material out of swap
-// Note that VirtualLock does not provide this as a guarantee on Windows,
-// but, in practice, memory that has been VirtualLock'd almost never gets written to
-// the pagefile except in rare circumstances where memory is extremely low.
-#else
-#include <sys/mman.h>
-#include <limits.h> // for PAGESIZE
-#include <unistd.h> // for sysconf
-#endif
-
-LockedPageManager* LockedPageManager::_instance = NULL;
-boost::once_flag LockedPageManager::init_flag = BOOST_ONCE_INIT;
-
-/** Determine system page size in bytes */
-static inline size_t GetSystemPageSize()
-{
-    size_t page_size;
-#if defined(WIN32)
-    SYSTEM_INFO sSysInfo;
-    GetSystemInfo(&sSysInfo);
-    page_size = sSysInfo.dwPageSize;
-#elif defined(PAGESIZE) // defined in limits.h
-    page_size = PAGESIZE;
-#else                   // assume some POSIX OS
-    page_size = sysconf(_SC_PAGESIZE);
-#endif
-    return page_size;
-}
-
-bool MemoryPageLocker::Lock(const void* addr, size_t len)
-{
-#ifdef WIN32
-    return VirtualLock(const_cast<void*>(addr), len) != 0;
-#else
-    return mlock(addr, len) == 0;
-#endif
-}
-
-bool MemoryPageLocker::Unlock(const void* addr, size_t len)
-{
-#ifdef WIN32
-    return VirtualUnlock(const_cast<void*>(addr), len) != 0;
-#else
-    return munlock(addr, len) == 0;
-#endif
-}
-
-LockedPageManager::LockedPageManager() : LockedPageManagerBase<MemoryPageLocker>(GetSystemPageSize())
-{
-}