1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <sys/types.h> 20 #include <unistd.h> 21 22 #include <string> 23 #include <vector> 24 25 #include <android-base/unique_fd.h> 26 27 namespace android { 28 namespace meminfo { 29 30 class PageAcct final { 31 // Class for per-page accounting by using kernel provided interfaces like 32 // kpagecount, kpageflags etc. 33 public: KernelHasPageIdle()34 static bool KernelHasPageIdle() { 35 return (access("/sys/kernel/mm/page_idle/bitmap", R_OK | W_OK) == 0); 36 } 37 38 bool InitPageAcct(bool pageidle_enable = false); 39 bool PageFlags(uint64_t pfn, uint64_t* flags); 40 bool PageMapCount(uint64_t pfn, uint64_t* mapcount); 41 42 int IsPageIdle(uint64_t pfn); 43 44 // The only way to create PageAcct object Instance()45 static PageAcct& Instance() { 46 static PageAcct instance; 47 return instance; 48 } 49 50 ~PageAcct() = default; 51 52 private: PageAcct()53 PageAcct() : kpagecount_fd_(-1), kpageflags_fd_(-1), pageidle_fd_(-1) {} 54 int MarkPageIdle(uint64_t pfn) const; 55 int GetPageIdle(uint64_t pfn) const; 56 57 // Non-copyable & Non-movable 58 PageAcct(const PageAcct&) = delete; 59 PageAcct& operator=(const PageAcct&) = delete; 60 PageAcct& operator=(PageAcct&&) = delete; 61 PageAcct(PageAcct&&) = delete; 62 63 ::android::base::unique_fd kpagecount_fd_; 64 ::android::base::unique_fd kpageflags_fd_; 65 ::android::base::unique_fd pageidle_fd_; 66 }; 67 68 // Returns if the page present bit is set in the value 69 // passed in. 70 bool page_present(uint64_t pagemap_val); 71 72 // Returns if the page swapped bit is set in the value 73 // passed in. 74 bool page_swapped(uint64_t pagemap_val); 75 76 // Returns the page frame number (physical page) from 77 // pagemap value 78 uint64_t page_pfn(uint64_t pagemap_val); 79 80 } // namespace meminfo 81 } // namespace android 82