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67 lines
2.4 KiB
67 lines
2.4 KiB
4 months ago
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// Copyright 2015 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_ANDROID_LIBRARY_LOADER_LIBRARY_PREFETCHER_H_
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#define BASE_ANDROID_LIBRARY_LOADER_LIBRARY_PREFETCHER_H_
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#include <jni.h>
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#include <stdint.h>
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#include "base/android/library_loader/anchor_functions_buildflags.h"
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#include "base/base_export.h"
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#include "base/gtest_prod_util.h"
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#include "base/macros.h"
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#if BUILDFLAG(SUPPORTS_CODE_ORDERING)
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namespace base {
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namespace android {
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// Forks and waits for a process prefetching the native library. This is done in
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// a forked process for the following reasons:
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// - Isolating the main process from mistakes in getting the address range, only
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// crashing the forked process in case of mistake.
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// - Not inflating the memory used by the main process uselessly, which could
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// increase its likelihood to be killed.
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// The forked process has background priority and, since it is not declared to
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// the Android runtime, can be killed at any time, which is not an issue here.
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class BASE_EXPORT NativeLibraryPrefetcher {
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public:
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// Finds the executable code range, forks a low priority process pre-fetching
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// it wait()s for the process to exit or die. If ordered_only is true, only
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// the ordered section is prefetched. See GetOrdrderedTextRange() in
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// library_prefetcher.cc.
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static void ForkAndPrefetchNativeLibrary(bool ordered_only);
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// Returns the percentage of the native library code currently resident in
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// memory, or -1 in case of error.
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static int PercentageOfResidentNativeLibraryCode();
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// Collects residency for the native library executable multiple times, then
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// dumps it to disk.
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static void PeriodicallyCollectResidency();
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// Calls madvise() on the native library executable, using orderfile
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// information to decide how to advise each part of the library.
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static void MadviseForOrderfile();
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private:
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// Returns the percentage of [start, end] currently resident in
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// memory, or -1 in case of error.
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static int PercentageOfResidentCode(size_t start, size_t end);
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FRIEND_TEST_ALL_PREFIXES(NativeLibraryPrefetcherTest,
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TestPercentageOfResidentCode);
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DISALLOW_IMPLICIT_CONSTRUCTORS(NativeLibraryPrefetcher);
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};
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} // namespace android
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} // namespace base
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#endif // BUILDFLAG(SUPPORTS_CODE_ORDERING)
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#endif // BASE_ANDROID_LIBRARY_LOADER_LIBRARY_PREFETCHER_H_
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