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231 lines
5.2 KiB
231 lines
5.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* |
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* A test for the patch "Allow compaction of unevictable pages". |
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* With this patch we should be able to allocate at least 1/4 |
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* of RAM in huge pages. Without the patch much less is |
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* allocated. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <sys/mman.h> |
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#include <sys/resource.h> |
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#include <fcntl.h> |
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#include <errno.h> |
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#include <unistd.h> |
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#include <string.h> |
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#include "../kselftest.h" |
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#define MAP_SIZE_MB 100 |
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#define MAP_SIZE (MAP_SIZE_MB * 1024 * 1024) |
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struct map_list { |
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void *map; |
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struct map_list *next; |
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}; |
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int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize) |
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{ |
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char buffer[256] = {0}; |
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char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'"; |
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FILE *cmdfile = popen(cmd, "r"); |
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if (!(fgets(buffer, sizeof(buffer), cmdfile))) { |
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perror("Failed to read meminfo\n"); |
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return -1; |
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} |
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pclose(cmdfile); |
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*memfree = atoll(buffer); |
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cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'"; |
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cmdfile = popen(cmd, "r"); |
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if (!(fgets(buffer, sizeof(buffer), cmdfile))) { |
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perror("Failed to read meminfo\n"); |
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return -1; |
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} |
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pclose(cmdfile); |
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*hugepagesize = atoll(buffer); |
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return 0; |
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} |
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int prereq(void) |
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{ |
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char allowed; |
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int fd; |
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fd = open("/proc/sys/vm/compact_unevictable_allowed", |
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O_RDONLY | O_NONBLOCK); |
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if (fd < 0) { |
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perror("Failed to open\n" |
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"/proc/sys/vm/compact_unevictable_allowed\n"); |
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return -1; |
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} |
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if (read(fd, &allowed, sizeof(char)) != sizeof(char)) { |
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perror("Failed to read from\n" |
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"/proc/sys/vm/compact_unevictable_allowed\n"); |
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close(fd); |
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return -1; |
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} |
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close(fd); |
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if (allowed == '1') |
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return 0; |
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return -1; |
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} |
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int check_compaction(unsigned long mem_free, unsigned int hugepage_size) |
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{ |
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int fd; |
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int compaction_index = 0; |
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char initial_nr_hugepages[10] = {0}; |
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char nr_hugepages[10] = {0}; |
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/* We want to test with 80% of available memory. Else, OOM killer comes |
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in to play */ |
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mem_free = mem_free * 0.8; |
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fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK); |
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if (fd < 0) { |
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perror("Failed to open /proc/sys/vm/nr_hugepages"); |
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return -1; |
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} |
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if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) { |
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perror("Failed to read from /proc/sys/vm/nr_hugepages"); |
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goto close_fd; |
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} |
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/* Start with the initial condition of 0 huge pages*/ |
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if (write(fd, "0", sizeof(char)) != sizeof(char)) { |
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perror("Failed to write 0 to /proc/sys/vm/nr_hugepages\n"); |
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goto close_fd; |
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} |
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lseek(fd, 0, SEEK_SET); |
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/* Request a large number of huge pages. The Kernel will allocate |
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as much as it can */ |
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if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) { |
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perror("Failed to write 100000 to /proc/sys/vm/nr_hugepages\n"); |
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goto close_fd; |
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} |
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lseek(fd, 0, SEEK_SET); |
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if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) { |
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perror("Failed to re-read from /proc/sys/vm/nr_hugepages\n"); |
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goto close_fd; |
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} |
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/* We should have been able to request at least 1/3 rd of the memory in |
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huge pages */ |
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compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size); |
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if (compaction_index > 3) { |
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printf("No of huge pages allocated = %d\n", |
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(atoi(nr_hugepages))); |
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fprintf(stderr, "ERROR: Less that 1/%d of memory is available\n" |
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"as huge pages\n", compaction_index); |
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goto close_fd; |
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} |
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printf("No of huge pages allocated = %d\n", |
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(atoi(nr_hugepages))); |
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lseek(fd, 0, SEEK_SET); |
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if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages)) |
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!= strlen(initial_nr_hugepages)) { |
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perror("Failed to write value to /proc/sys/vm/nr_hugepages\n"); |
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goto close_fd; |
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} |
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close(fd); |
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return 0; |
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close_fd: |
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close(fd); |
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printf("Not OK. Compaction test failed."); |
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return -1; |
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} |
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int main(int argc, char **argv) |
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{ |
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struct rlimit lim; |
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struct map_list *list, *entry; |
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size_t page_size, i; |
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void *map = NULL; |
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unsigned long mem_free = 0; |
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unsigned long hugepage_size = 0; |
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long mem_fragmentable_MB = 0; |
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if (prereq() != 0) { |
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printf("Either the sysctl compact_unevictable_allowed is not\n" |
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"set to 1 or couldn't read the proc file.\n" |
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"Skipping the test\n"); |
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return KSFT_SKIP; |
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} |
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lim.rlim_cur = RLIM_INFINITY; |
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lim.rlim_max = RLIM_INFINITY; |
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if (setrlimit(RLIMIT_MEMLOCK, &lim)) { |
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perror("Failed to set rlimit:\n"); |
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return -1; |
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} |
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page_size = getpagesize(); |
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list = NULL; |
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if (read_memory_info(&mem_free, &hugepage_size) != 0) { |
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printf("ERROR: Cannot read meminfo\n"); |
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return -1; |
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} |
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mem_fragmentable_MB = mem_free * 0.8 / 1024; |
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while (mem_fragmentable_MB > 0) { |
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map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, |
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MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0); |
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if (map == MAP_FAILED) |
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break; |
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entry = malloc(sizeof(struct map_list)); |
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if (!entry) { |
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munmap(map, MAP_SIZE); |
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break; |
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} |
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entry->map = map; |
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entry->next = list; |
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list = entry; |
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/* Write something (in this case the address of the map) to |
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* ensure that KSM can't merge the mapped pages |
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*/ |
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for (i = 0; i < MAP_SIZE; i += page_size) |
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*(unsigned long *)(map + i) = (unsigned long)map + i; |
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mem_fragmentable_MB -= MAP_SIZE_MB; |
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} |
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for (entry = list; entry != NULL; entry = entry->next) { |
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munmap(entry->map, MAP_SIZE); |
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if (!entry->next) |
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break; |
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entry = entry->next; |
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} |
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if (check_compaction(mem_free, hugepage_size) == 0) |
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return 0; |
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return -1; |
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}
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