1 /* 2 * Copyright (C) 2014 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 #include <assert.h> 18 #include <inttypes.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <stdint.h> 22 #include <sys/types.h> 23 #include <unistd.h> 24 #include <fcntl.h> 25 26 // This is an extremely simplified version of libpagemap. 27 28 #define _BITS(x, offset, bits) (((x) >> offset) & ((1LL << (bits)) - 1)) 29 30 #define PAGEMAP_PRESENT(x) (_BITS(x, 63, 1)) 31 #define PAGEMAP_SWAPPED(x) (_BITS(x, 62, 1)) 32 #define PAGEMAP_SHIFT(x) (_BITS(x, 55, 6)) 33 #define PAGEMAP_PFN(x) (_BITS(x, 0, 55)) 34 #define PAGEMAP_SWAP_OFFSET(x) (_BITS(x, 5, 50)) 35 #define PAGEMAP_SWAP_TYPE(x) (_BITS(x, 0, 5)) 36 37 static bool ReadData(int fd, unsigned long place, uint64_t *data) { 38 if (lseek(fd, place * sizeof(uint64_t), SEEK_SET) < 0) { 39 return false; 40 } 41 if (read(fd, (void*)data, sizeof(uint64_t)) != (ssize_t)sizeof(uint64_t)) { 42 return false; 43 } 44 return true; 45 } 46 47 size_t GetPssBytes() { 48 FILE* maps = fopen("/proc/self/maps", "r"); 49 assert(maps != NULL); 50 51 int pagecount_fd = open("/proc/kpagecount", O_RDONLY); 52 assert(pagecount_fd >= 0); 53 54 int pagemap_fd = open("/proc/self/pagemap", O_RDONLY); 55 assert(pagemap_fd >= 0); 56 57 char line[4096]; 58 size_t total_pss = 0; 59 int pagesize = getpagesize(); 60 while (fgets(line, sizeof(line), maps)) { 61 uintptr_t start, end; 62 if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR " ", &start, &end) != 2) { 63 total_pss = 0; 64 break; 65 } 66 for (size_t page = start/pagesize; page < end/pagesize; page++) { 67 uint64_t data; 68 if (ReadData(pagemap_fd, page, &data)) { 69 if (PAGEMAP_PRESENT(data) && !PAGEMAP_SWAPPED(data)) { 70 uint64_t count; 71 if (ReadData(pagecount_fd, PAGEMAP_PFN(data), &count)) { 72 total_pss += (count >= 1) ? pagesize / count : 0; 73 } 74 } 75 } 76 } 77 } 78 79 fclose(maps); 80 81 close(pagecount_fd); 82 close(pagemap_fd); 83 84 return total_pss; 85 } 86
