/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <pagemap/pagemap.h>
#define MAX_FILENAME 64
#define GROWTH_FACTOR 10
#define NO_PATTERN 0x100
#define PR_SORTED 1
#define PR_VERBOSE 2
#define PR_ALL 4
struct vaddr {
unsigned long addr;
size_t num_pages;
pid_t pid;
};
struct ksm_page {
uint64_t count;
uint32_t hash;
struct vaddr *vaddr;
size_t vaddr_len, vaddr_size;
size_t vaddr_count;
uint16_t pattern;
};
struct ksm_pages {
struct ksm_page *pages;
size_t len, size;
};
static void usage(char *myname);
static int getprocname(pid_t pid, char *buf, int len);
static int read_pages(struct ksm_pages *kp, pm_map_t **maps, size_t num_maps, uint8_t pr_flags);
static void print_pages(struct ksm_pages *kp, uint8_t pr_flags);
static void free_pages(struct ksm_pages *kp, uint8_t pr_flags);
static bool is_pattern(uint8_t *data, size_t len);
static int cmp_pages(const void *a, const void *b);
extern uint32_t hashword(const uint32_t *, size_t, int32_t);
int main(int argc, char *argv[]) {
pm_kernel_t *ker;
pm_process_t *proc;
pid_t *pids;
size_t num_procs;
size_t i;
pm_map_t **maps;
size_t num_maps;
char cmdline[256]; // this must be within the range of int
int error;
int rc = EXIT_SUCCESS;
uint8_t pr_flags = 0;
struct ksm_pages kp;
memset(&kp, 0, sizeof(kp));
opterr = 0;
do {
int c = getopt(argc, argv, "hvsa");
if (c == -1)
break;
switch (c) {
case 'a':
pr_flags |= PR_ALL;
break;
case 's':
pr_flags |= PR_SORTED;
break;
case 'v':
pr_flags |= PR_VERBOSE;
break;
case 'h':
usage(argv[0]);
exit(EXIT_SUCCESS);
case '?':
fprintf(stderr, "unknown option: %c\n", optopt);
usage(argv[0]);
exit(EXIT_FAILURE);
}
} while (1);
error = pm_kernel_create(&ker);
if (error) {
fprintf(stderr, "Error creating kernel interface -- "
"does this kernel have pagemap?\n");
exit(EXIT_FAILURE);
}
if (pr_flags & PR_ALL) {
error = pm_kernel_pids(ker, &pids, &num_procs);
if (error) {
fprintf(stderr, "Error listing processes.\n");
exit(EXIT_FAILURE);
}
} else {
if (optind != argc - 1) {
usage(argv[0]);
exit(EXIT_FAILURE);
}
pids = malloc(sizeof(*pids));
if (pids == NULL) {
fprintf(stderr, "Error allocating pid memory\n");
exit(EXIT_FAILURE);
}
*pids = strtoul(argv[optind], NULL, 10);
if (*pids == 0) {
fprintf(stderr, "Invalid PID\n");
rc = EXIT_FAILURE;
goto exit;
}
num_procs = 1;
if (getprocname(*pids, cmdline, sizeof(cmdline)) < 0) {
cmdline[0] = '\0';
}
printf("%s (%u):\n", cmdline, *pids);
}
printf("Warning: this tool only compares the KSM CRCs of pages, there is a chance of "
"collisions\n");
for (i = 0; i < num_procs; i++) {
error = pm_process_create(ker, pids[i], &proc);
if (error) {
fprintf(stderr, "warning: could not create process interface for %d\n", pids[i]);
rc = EXIT_FAILURE;
goto exit;
}
error = pm_process_maps(proc, &maps, &num_maps);
if (error) {
pm_process_destroy(proc);
fprintf(stderr, "warning: could not read process map for %d\n", pids[i]);
rc = EXIT_FAILURE;
goto exit;
}
if (read_pages(&kp, maps, num_maps, pr_flags) < 0) {
free(maps);
pm_process_destroy(proc);
rc = EXIT_FAILURE;
goto exit;
}
free(maps);
pm_process_destroy(proc);
}
if (pr_flags & PR_SORTED) {
qsort(kp.pages, kp.len, sizeof(*kp.pages), cmp_pages);
}
print_pages(&kp, pr_flags);
exit:
free_pages(&kp, pr_flags);
free(pids);
return rc;
}
static int read_pages(struct ksm_pages *kp, pm_map_t **maps, size_t num_maps, uint8_t pr_flags) {
size_t i, j, k;
uint64_t *pagemap;
size_t map_len;
uint64_t flags;
pm_kernel_t *ker;
int error;
unsigned long vaddr;
int fd;
off_t off;
char filename[MAX_FILENAME];
uint32_t *data;
uint32_t hash;
int rc = 0;
struct ksm_page *cur_page;
pid_t pid;
if (num_maps == 0)
return 0;
pid = pm_process_pid(maps[0]->proc);
ker = maps[0]->proc->ker;
error = snprintf(filename, MAX_FILENAME, "/proc/%d/mem", pid);
if (error < 0 || error >= MAX_FILENAME) {
return -1;
}
data = malloc(pm_kernel_pagesize(ker));
if (data == NULL) {
fprintf(stderr, "warning: not enough memory to malloc data buffer\n");
return -1;
}
fd = open(filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "warning: could not open %s\n", filename);
rc = -1;
goto err_open;
}
for (i = 0; i < num_maps; i++) {
error = pm_map_pagemap(maps[i], &pagemap, &map_len);
if (error) {
fprintf(stderr, "warning: could not read the pagemap of %d\n",
pm_process_pid(maps[i]->proc));
continue;
}
for (j = 0; j < map_len; j++) {
error = pm_kernel_flags(ker, PM_PAGEMAP_PFN(pagemap[j]), &flags);
if (error) {
fprintf(stderr, "warning: could not read flags for pfn at address 0x%016" PRIx64 "\n",
pagemap[i]);
continue;
}
if (!(flags & PM_PAGE_KSM)) {
continue;
}
vaddr = pm_map_start(maps[i]) + j * pm_kernel_pagesize(ker);
off = lseek(fd, vaddr, SEEK_SET);
if (off == (off_t)-1) {
fprintf(stderr, "warning: could not lseek to 0x%08lx\n", vaddr);
continue;
}
ssize_t len = read(fd, data, pm_kernel_pagesize(ker));
if (len != pm_kernel_pagesize(ker)) {
fprintf(stderr, "warning: could not read page at 0x%08lx\n", vaddr);
continue;
}
hash = hashword(data, pm_kernel_pagesize(ker) / sizeof(*data), 17);
for (k = 0; k < kp->len; k++) {
if (kp->pages[k].hash == hash) break;
}
if (k == kp->len) {
if (kp->len == kp->size) {
struct ksm_page *tmp = realloc(kp->pages,
(kp->size + GROWTH_FACTOR) * sizeof(*kp->pages));
if (tmp == NULL) {
fprintf(stderr, "warning: not enough memory to realloc pages struct\n");
free(pagemap);
rc = -1;
goto err_realloc;
}
memset(&tmp[k], 0, sizeof(tmp[k]) * GROWTH_FACTOR);
kp->pages = tmp;
kp->size += GROWTH_FACTOR;
}
rc = pm_kernel_count(ker, PM_PAGEMAP_PFN(pagemap[j]), &kp->pages[kp->len].count);
if (rc) {
fprintf(stderr, "error reading page count\n");
free(pagemap);
goto err_count;
}
kp->pages[kp->len].hash = hash;
kp->pages[kp->len].pattern =
is_pattern((uint8_t *)data, pm_kernel_pagesize(ker)) ?
(data[0] & 0xFF) : NO_PATTERN;
kp->len++;
}
cur_page = &kp->pages[k];
if (pr_flags & PR_VERBOSE) {
if (cur_page->vaddr_len > 0 &&
cur_page->vaddr[cur_page->vaddr_len - 1].pid == pid &&
cur_page->vaddr[cur_page->vaddr_len - 1].addr ==
vaddr - (cur_page->vaddr[cur_page->vaddr_len - 1].num_pages *
pm_kernel_pagesize(ker))) {
cur_page->vaddr[cur_page->vaddr_len - 1].num_pages++;
} else {
if (cur_page->vaddr_len == cur_page->vaddr_size) {
struct vaddr *tmp = realloc(cur_page->vaddr,
(cur_page->vaddr_size + GROWTH_FACTOR) * sizeof(*(cur_page->vaddr)));
if (tmp == NULL) {
fprintf(stderr, "warning: not enough memory to realloc vaddr array\n");
free(pagemap);
rc = -1;
goto err_realloc;
}
memset(&tmp[cur_page->vaddr_len], 0, sizeof(tmp[cur_page->vaddr_len]) * GROWTH_FACTOR);
cur_page->vaddr = tmp;
cur_page->vaddr_size += GROWTH_FACTOR;
}
cur_page->vaddr[cur_page->vaddr_len].addr = vaddr;
cur_page->vaddr[cur_page->vaddr_len].num_pages = 1;
cur_page->vaddr[cur_page->vaddr_len].pid = pid;
cur_page->vaddr_len++;
}
}
cur_page->vaddr_count++;
}
free(pagemap);
}
goto no_err;
err_realloc:
err_count:
if (pr_flags & PR_VERBOSE) {
for (i = 0; i < kp->len; i++) {
free(kp->pages[i].vaddr);
}
}
free(kp->pages);
no_err:
close(fd);
err_open:
free(data);
return rc;
}
static void print_pages(struct ksm_pages *kp, uint8_t pr_flags) {
size_t i, j, k;
char suffix[13];
int index;
for (i = 0; i < kp->len; i++) {
if (kp->pages[i].pattern != NO_PATTERN) {
printf("0x%02x byte pattern: ", kp->pages[i].pattern);
} else {
printf("KSM CRC 0x%08x:", kp->pages[i].hash);
}
printf(" %4zu page", kp->pages[i].vaddr_count);
if (kp->pages[i].vaddr_count > 1) {
printf("s");
}
if (!(pr_flags & PR_ALL)) {
printf(" (%" PRIu64 " reference", kp->pages[i].count);
if (kp->pages[i].count > 1) {
printf("s");
}
printf(")");
}
printf("\n");
if (pr_flags & PR_VERBOSE) {
j = 0;
while (j < kp->pages[i].vaddr_len) {
printf(" ");
for (k = 0; k < 8 && j < kp->pages[i].vaddr_len; k++, j++) {
printf(" 0x%08lx", kp->pages[i].vaddr[j].addr);
index = snprintf(suffix, sizeof(suffix), ":%zu",
kp->pages[i].vaddr[j].num_pages);
if (pr_flags & PR_ALL) {
index += snprintf(suffix + index, sizeof(suffix) - index, "[%d]",
kp->pages[i].vaddr[j].pid);
}
printf("%-12s", suffix);
}
printf("\n");
}
}
}
}
static void free_pages(struct ksm_pages *kp, uint8_t pr_flags) {
size_t i;
if (pr_flags & PR_VERBOSE) {
for (i = 0; i < kp->len; i++) {
free(kp->pages[i].vaddr);
}
}
free(kp->pages);
}
static void usage(char *myname) {
fprintf(stderr, "Usage: %s [-s | -v | -a | -h ] <pid>\n"
" -s Sort pages by usage count.\n"
" -v Verbose: print virtual addresses.\n"
" -a Display all the KSM pages in the system. Ignore the pid argument.\n"
" -h Display this help screen.\n",
myname);
}
static int cmp_pages(const void *a, const void *b) {
const struct ksm_page *pg_a = a;
const struct ksm_page *pg_b = b;
int cmp = pg_b->vaddr_count - pg_a->vaddr_count;
return cmp ? cmp : pg_b->count - pg_a->count;
}
static bool is_pattern(uint8_t *data, size_t len) {
size_t i;
uint8_t first_byte = data[0];
for (i = 1; i < len; i++) {
if (first_byte != data[i]) return false;
}
return true;
}
/*
* Get the process name for a given PID. Inserts the process name into buffer
* buf of length len. The size of the buffer must be greater than zero to get
* any useful output.
*
* Note that fgets(3) only declares length as an int, so our buffer size is
* also declared as an int.
*
* Returns 0 on success, a positive value on partial success, and -1 on
* failure. Other interesting values:
* 1 on failure to create string to examine proc cmdline entry
* 2 on failure to open proc cmdline entry
* 3 on failure to read proc cmdline entry
*/
static int getprocname(pid_t pid, char *buf, int len) {
char *filename;
FILE *f;
int rc = 0;
static const char* unknown_cmdline = "<unknown>";
if (len <= 0) {
return -1;
}
if (asprintf(&filename, "/proc/%d/cmdline", (int)pid) < 0) {
rc = 1;
goto exit;
}
f = fopen(filename, "r");
if (f == NULL) {
rc = 2;
goto releasefilename;
}
if (fgets(buf, len, f) == NULL) {
rc = 3;
goto closefile;
}
closefile:
(void) fclose(f);
releasefilename:
free(filename);
exit:
if (rc != 0) {
/*
* The process went away before we could read its process name. Try
* to give the user "<unknown>" here, but otherwise they get to look
* at a blank.
*/
if (strlcpy(buf, unknown_cmdline, (size_t)len) >= (size_t)len) {
rc = 4;
}
}
return rc;
}