1 /*
2 * Copyright (C) 2013 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 #define LOG_TAG "lowmemorykiller"
18
19 #include <arpa/inet.h>
20 #include <errno.h>
21 #include <signal.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <time.h>
25 #include <sys/cdefs.h>
26 #include <sys/epoll.h>
27 #include <sys/eventfd.h>
28 #include <sys/mman.h>
29 #include <sys/socket.h>
30 #include <sys/types.h>
31 #include <unistd.h>
32
33 #include <cutils/sockets.h>
34 #include <log/log.h>
35 #include <processgroup/processgroup.h>
36
37 #ifndef __unused
38 #define __unused __attribute__((__unused__))
39 #endif
40
41 #define MEMCG_SYSFS_PATH "/dev/memcg/"
42 #define MEMPRESSURE_WATCH_LEVEL "low"
43 #define ZONEINFO_PATH "/proc/zoneinfo"
44 #define LINE_MAX 128
45
46 #define INKERNEL_MINFREE_PATH "/sys/module/lowmemorykiller/parameters/minfree"
47 #define INKERNEL_ADJ_PATH "/sys/module/lowmemorykiller/parameters/adj"
48
49 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
50
51 enum lmk_cmd {
52 LMK_TARGET,
53 LMK_PROCPRIO,
54 LMK_PROCREMOVE,
55 };
56
57 #define MAX_TARGETS 6
58 /*
59 * longest is LMK_TARGET followed by MAX_TARGETS each minfree and minkillprio
60 * values
61 */
62 #define CTRL_PACKET_MAX (sizeof(int) * (MAX_TARGETS * 2 + 1))
63
64 /* default to old in-kernel interface if no memory pressure events */
65 static int use_inkernel_interface = 1;
66
67 /* memory pressure level medium event */
68 static int mpevfd;
69
70 /* control socket listen and data */
71 static int ctrl_lfd;
72 static int ctrl_dfd = -1;
73 static int ctrl_dfd_reopened; /* did we reopen ctrl conn on this loop? */
74
75 /* 1 memory pressure level, 1 ctrl listen socket, 1 ctrl data socket */
76 #define MAX_EPOLL_EVENTS 3
77 static int epollfd;
78 static int maxevents;
79
80 /* OOM score values used by both kernel and framework */
81 #define OOM_SCORE_ADJ_MIN (-1000)
82 #define OOM_SCORE_ADJ_MAX 1000
83
84 static int lowmem_adj[MAX_TARGETS];
85 static int lowmem_minfree[MAX_TARGETS];
86 static int lowmem_targets_size;
87
88 struct sysmeminfo {
89 int nr_free_pages;
90 int nr_file_pages;
91 int nr_shmem;
92 int totalreserve_pages;
93 };
94
95 struct adjslot_list {
96 struct adjslot_list *next;
97 struct adjslot_list *prev;
98 };
99
100 struct proc {
101 struct adjslot_list asl;
102 int pid;
103 uid_t uid;
104 int oomadj;
105 struct proc *pidhash_next;
106 };
107
108 #define PIDHASH_SZ 1024
109 static struct proc *pidhash[PIDHASH_SZ];
110 #define pid_hashfn(x) ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
111
112 #define ADJTOSLOT(adj) (adj + -OOM_SCORE_ADJ_MIN)
113 static struct adjslot_list procadjslot_list[ADJTOSLOT(OOM_SCORE_ADJ_MAX) + 1];
114
115 /*
116 * Wait 1-2 seconds for the death report of a killed process prior to
117 * considering killing more processes.
118 */
119 #define KILL_TIMEOUT 2
120 /* Time of last process kill we initiated, stop me before I kill again */
121 static time_t kill_lasttime;
122
123 /* PAGE_SIZE / 1024 */
124 static long page_k;
125
read_all(int fd,char * buf,size_t max_len)126 static ssize_t read_all(int fd, char *buf, size_t max_len)
127 {
128 ssize_t ret = 0;
129
130 while (max_len > 0) {
131 ssize_t r = read(fd, buf, max_len);
132 if (r == 0) {
133 break;
134 }
135 if (r == -1) {
136 return -1;
137 }
138 ret += r;
139 buf += r;
140 max_len -= r;
141 }
142
143 return ret;
144 }
145
pid_lookup(int pid)146 static struct proc *pid_lookup(int pid) {
147 struct proc *procp;
148
149 for (procp = pidhash[pid_hashfn(pid)]; procp && procp->pid != pid;
150 procp = procp->pidhash_next)
151 ;
152
153 return procp;
154 }
155
adjslot_insert(struct adjslot_list * head,struct adjslot_list * new)156 static void adjslot_insert(struct adjslot_list *head, struct adjslot_list *new)
157 {
158 struct adjslot_list *next = head->next;
159 new->prev = head;
160 new->next = next;
161 next->prev = new;
162 head->next = new;
163 }
164
adjslot_remove(struct adjslot_list * old)165 static void adjslot_remove(struct adjslot_list *old)
166 {
167 struct adjslot_list *prev = old->prev;
168 struct adjslot_list *next = old->next;
169 next->prev = prev;
170 prev->next = next;
171 }
172
adjslot_tail(struct adjslot_list * head)173 static struct adjslot_list *adjslot_tail(struct adjslot_list *head) {
174 struct adjslot_list *asl = head->prev;
175
176 return asl == head ? NULL : asl;
177 }
178
proc_slot(struct proc * procp)179 static void proc_slot(struct proc *procp) {
180 int adjslot = ADJTOSLOT(procp->oomadj);
181
182 adjslot_insert(&procadjslot_list[adjslot], &procp->asl);
183 }
184
proc_unslot(struct proc * procp)185 static void proc_unslot(struct proc *procp) {
186 adjslot_remove(&procp->asl);
187 }
188
proc_insert(struct proc * procp)189 static void proc_insert(struct proc *procp) {
190 int hval = pid_hashfn(procp->pid);
191
192 procp->pidhash_next = pidhash[hval];
193 pidhash[hval] = procp;
194 proc_slot(procp);
195 }
196
pid_remove(int pid)197 static int pid_remove(int pid) {
198 int hval = pid_hashfn(pid);
199 struct proc *procp;
200 struct proc *prevp;
201
202 for (procp = pidhash[hval], prevp = NULL; procp && procp->pid != pid;
203 procp = procp->pidhash_next)
204 prevp = procp;
205
206 if (!procp)
207 return -1;
208
209 if (!prevp)
210 pidhash[hval] = procp->pidhash_next;
211 else
212 prevp->pidhash_next = procp->pidhash_next;
213
214 proc_unslot(procp);
215 free(procp);
216 return 0;
217 }
218
writefilestring(char * path,char * s)219 static void writefilestring(char *path, char *s) {
220 int fd = open(path, O_WRONLY | O_CLOEXEC);
221 int len = strlen(s);
222 int ret;
223
224 if (fd < 0) {
225 ALOGE("Error opening %s; errno=%d", path, errno);
226 return;
227 }
228
229 ret = write(fd, s, len);
230 if (ret < 0) {
231 ALOGE("Error writing %s; errno=%d", path, errno);
232 } else if (ret < len) {
233 ALOGE("Short write on %s; length=%d", path, ret);
234 }
235
236 close(fd);
237 }
238
cmd_procprio(int pid,int uid,int oomadj)239 static void cmd_procprio(int pid, int uid, int oomadj) {
240 struct proc *procp;
241 char path[80];
242 char val[20];
243
244 if (oomadj < OOM_SCORE_ADJ_MIN || oomadj > OOM_SCORE_ADJ_MAX) {
245 ALOGE("Invalid PROCPRIO oomadj argument %d", oomadj);
246 return;
247 }
248
249 snprintf(path, sizeof(path), "/proc/%d/oom_score_adj", pid);
250 snprintf(val, sizeof(val), "%d", oomadj);
251 writefilestring(path, val);
252
253 if (use_inkernel_interface)
254 return;
255
256 procp = pid_lookup(pid);
257 if (!procp) {
258 procp = malloc(sizeof(struct proc));
259 if (!procp) {
260 // Oh, the irony. May need to rebuild our state.
261 return;
262 }
263
264 procp->pid = pid;
265 procp->uid = uid;
266 procp->oomadj = oomadj;
267 proc_insert(procp);
268 } else {
269 proc_unslot(procp);
270 procp->oomadj = oomadj;
271 proc_slot(procp);
272 }
273 }
274
cmd_procremove(int pid)275 static void cmd_procremove(int pid) {
276 if (use_inkernel_interface)
277 return;
278
279 pid_remove(pid);
280 kill_lasttime = 0;
281 }
282
cmd_target(int ntargets,int * params)283 static void cmd_target(int ntargets, int *params) {
284 int i;
285
286 if (ntargets > (int)ARRAY_SIZE(lowmem_adj))
287 return;
288
289 for (i = 0; i < ntargets; i++) {
290 lowmem_minfree[i] = ntohl(*params++);
291 lowmem_adj[i] = ntohl(*params++);
292 }
293
294 lowmem_targets_size = ntargets;
295
296 if (use_inkernel_interface) {
297 char minfreestr[128];
298 char killpriostr[128];
299
300 minfreestr[0] = '\0';
301 killpriostr[0] = '\0';
302
303 for (i = 0; i < lowmem_targets_size; i++) {
304 char val[40];
305
306 if (i) {
307 strlcat(minfreestr, ",", sizeof(minfreestr));
308 strlcat(killpriostr, ",", sizeof(killpriostr));
309 }
310
311 snprintf(val, sizeof(val), "%d", lowmem_minfree[i]);
312 strlcat(minfreestr, val, sizeof(minfreestr));
313 snprintf(val, sizeof(val), "%d", lowmem_adj[i]);
314 strlcat(killpriostr, val, sizeof(killpriostr));
315 }
316
317 writefilestring(INKERNEL_MINFREE_PATH, minfreestr);
318 writefilestring(INKERNEL_ADJ_PATH, killpriostr);
319 }
320 }
321
ctrl_data_close(void)322 static void ctrl_data_close(void) {
323 ALOGI("Closing Activity Manager data connection");
324 close(ctrl_dfd);
325 ctrl_dfd = -1;
326 maxevents--;
327 }
328
ctrl_data_read(char * buf,size_t bufsz)329 static int ctrl_data_read(char *buf, size_t bufsz) {
330 int ret = 0;
331
332 ret = read(ctrl_dfd, buf, bufsz);
333
334 if (ret == -1) {
335 ALOGE("control data socket read failed; errno=%d", errno);
336 } else if (ret == 0) {
337 ALOGE("Got EOF on control data socket");
338 ret = -1;
339 }
340
341 return ret;
342 }
343
ctrl_command_handler(void)344 static void ctrl_command_handler(void) {
345 int ibuf[CTRL_PACKET_MAX / sizeof(int)];
346 int len;
347 int cmd = -1;
348 int nargs;
349 int targets;
350
351 len = ctrl_data_read((char *)ibuf, CTRL_PACKET_MAX);
352 if (len <= 0)
353 return;
354
355 nargs = len / sizeof(int) - 1;
356 if (nargs < 0)
357 goto wronglen;
358
359 cmd = ntohl(ibuf[0]);
360
361 switch(cmd) {
362 case LMK_TARGET:
363 targets = nargs / 2;
364 if (nargs & 0x1 || targets > (int)ARRAY_SIZE(lowmem_adj))
365 goto wronglen;
366 cmd_target(targets, &ibuf[1]);
367 break;
368 case LMK_PROCPRIO:
369 if (nargs != 3)
370 goto wronglen;
371 cmd_procprio(ntohl(ibuf[1]), ntohl(ibuf[2]), ntohl(ibuf[3]));
372 break;
373 case LMK_PROCREMOVE:
374 if (nargs != 1)
375 goto wronglen;
376 cmd_procremove(ntohl(ibuf[1]));
377 break;
378 default:
379 ALOGE("Received unknown command code %d", cmd);
380 return;
381 }
382
383 return;
384
385 wronglen:
386 ALOGE("Wrong control socket read length cmd=%d len=%d", cmd, len);
387 }
388
ctrl_data_handler(uint32_t events)389 static void ctrl_data_handler(uint32_t events) {
390 if (events & EPOLLHUP) {
391 ALOGI("ActivityManager disconnected");
392 if (!ctrl_dfd_reopened)
393 ctrl_data_close();
394 } else if (events & EPOLLIN) {
395 ctrl_command_handler();
396 }
397 }
398
ctrl_connect_handler(uint32_t events __unused)399 static void ctrl_connect_handler(uint32_t events __unused) {
400 struct sockaddr_storage ss;
401 struct sockaddr *addrp = (struct sockaddr *)&ss;
402 socklen_t alen;
403 struct epoll_event epev;
404
405 if (ctrl_dfd >= 0) {
406 ctrl_data_close();
407 ctrl_dfd_reopened = 1;
408 }
409
410 alen = sizeof(ss);
411 ctrl_dfd = accept(ctrl_lfd, addrp, &alen);
412
413 if (ctrl_dfd < 0) {
414 ALOGE("lmkd control socket accept failed; errno=%d", errno);
415 return;
416 }
417
418 ALOGI("ActivityManager connected");
419 maxevents++;
420 epev.events = EPOLLIN;
421 epev.data.ptr = (void *)ctrl_data_handler;
422 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, ctrl_dfd, &epev) == -1) {
423 ALOGE("epoll_ctl for data connection socket failed; errno=%d", errno);
424 ctrl_data_close();
425 return;
426 }
427 }
428
zoneinfo_parse_protection(char * cp)429 static int zoneinfo_parse_protection(char *cp) {
430 int max = 0;
431 int zoneval;
432 char *save_ptr;
433
434 for (cp = strtok_r(cp, "(), ", &save_ptr); cp; cp = strtok_r(NULL, "), ", &save_ptr)) {
435 zoneval = strtol(cp, &cp, 0);
436 if (zoneval > max)
437 max = zoneval;
438 }
439
440 return max;
441 }
442
zoneinfo_parse_line(char * line,struct sysmeminfo * mip)443 static void zoneinfo_parse_line(char *line, struct sysmeminfo *mip) {
444 char *cp = line;
445 char *ap;
446 char *save_ptr;
447
448 cp = strtok_r(line, " ", &save_ptr);
449 if (!cp)
450 return;
451
452 ap = strtok_r(NULL, " ", &save_ptr);
453 if (!ap)
454 return;
455
456 if (!strcmp(cp, "nr_free_pages"))
457 mip->nr_free_pages += strtol(ap, NULL, 0);
458 else if (!strcmp(cp, "nr_file_pages"))
459 mip->nr_file_pages += strtol(ap, NULL, 0);
460 else if (!strcmp(cp, "nr_shmem"))
461 mip->nr_shmem += strtol(ap, NULL, 0);
462 else if (!strcmp(cp, "high"))
463 mip->totalreserve_pages += strtol(ap, NULL, 0);
464 else if (!strcmp(cp, "protection:"))
465 mip->totalreserve_pages += zoneinfo_parse_protection(ap);
466 }
467
zoneinfo_parse(struct sysmeminfo * mip)468 static int zoneinfo_parse(struct sysmeminfo *mip) {
469 int fd;
470 ssize_t size;
471 char buf[PAGE_SIZE];
472 char *save_ptr;
473 char *line;
474
475 memset(mip, 0, sizeof(struct sysmeminfo));
476
477 fd = open(ZONEINFO_PATH, O_RDONLY | O_CLOEXEC);
478 if (fd == -1) {
479 ALOGE("%s open: errno=%d", ZONEINFO_PATH, errno);
480 return -1;
481 }
482
483 size = read_all(fd, buf, sizeof(buf) - 1);
484 if (size < 0) {
485 ALOGE("%s read: errno=%d", ZONEINFO_PATH, errno);
486 close(fd);
487 return -1;
488 }
489 ALOG_ASSERT((size_t)size < sizeof(buf) - 1, "/proc/zoneinfo too large");
490 buf[size] = 0;
491
492 for (line = strtok_r(buf, "\n", &save_ptr); line; line = strtok_r(NULL, "\n", &save_ptr))
493 zoneinfo_parse_line(line, mip);
494
495 close(fd);
496 return 0;
497 }
498
proc_get_size(int pid)499 static int proc_get_size(int pid) {
500 char path[PATH_MAX];
501 char line[LINE_MAX];
502 int fd;
503 int rss = 0;
504 int total;
505 ssize_t ret;
506
507 snprintf(path, PATH_MAX, "/proc/%d/statm", pid);
508 fd = open(path, O_RDONLY | O_CLOEXEC);
509 if (fd == -1)
510 return -1;
511
512 ret = read_all(fd, line, sizeof(line) - 1);
513 if (ret < 0) {
514 close(fd);
515 return -1;
516 }
517
518 sscanf(line, "%d %d ", &total, &rss);
519 close(fd);
520 return rss;
521 }
522
proc_get_name(int pid)523 static char *proc_get_name(int pid) {
524 char path[PATH_MAX];
525 static char line[LINE_MAX];
526 int fd;
527 char *cp;
528 ssize_t ret;
529
530 snprintf(path, PATH_MAX, "/proc/%d/cmdline", pid);
531 fd = open(path, O_RDONLY | O_CLOEXEC);
532 if (fd == -1)
533 return NULL;
534 ret = read_all(fd, line, sizeof(line) - 1);
535 close(fd);
536 if (ret < 0) {
537 return NULL;
538 }
539
540 cp = strchr(line, ' ');
541 if (cp)
542 *cp = '\0';
543
544 return line;
545 }
546
proc_adj_lru(int oomadj)547 static struct proc *proc_adj_lru(int oomadj) {
548 return (struct proc *)adjslot_tail(&procadjslot_list[ADJTOSLOT(oomadj)]);
549 }
550
551 /* Kill one process specified by procp. Returns the size of the process killed */
kill_one_process(struct proc * procp,int other_free,int other_file,int minfree,int min_score_adj,bool first)552 static int kill_one_process(struct proc *procp, int other_free, int other_file,
553 int minfree, int min_score_adj, bool first)
554 {
555 int pid = procp->pid;
556 uid_t uid = procp->uid;
557 char *taskname;
558 int tasksize;
559 int r;
560
561 taskname = proc_get_name(pid);
562 if (!taskname) {
563 pid_remove(pid);
564 return -1;
565 }
566
567 tasksize = proc_get_size(pid);
568 if (tasksize <= 0) {
569 pid_remove(pid);
570 return -1;
571 }
572
573 ALOGI("Killing '%s' (%d), uid %d, adj %d\n"
574 " to free %ldkB because cache %s%ldkB is below limit %ldkB for oom_adj %d\n"
575 " Free memory is %s%ldkB %s reserved",
576 taskname, pid, uid, procp->oomadj, tasksize * page_k,
577 first ? "" : "~", other_file * page_k, minfree * page_k, min_score_adj,
578 first ? "" : "~", other_free * page_k, other_free >= 0 ? "above" : "below");
579 r = kill(pid, SIGKILL);
580 killProcessGroup(uid, pid, SIGKILL);
581 pid_remove(pid);
582
583 if (r) {
584 ALOGE("kill(%d): errno=%d", procp->pid, errno);
585 return -1;
586 } else {
587 return tasksize;
588 }
589 }
590
591 /*
592 * Find a process to kill based on the current (possibly estimated) free memory
593 * and cached memory sizes. Returns the size of the killed processes.
594 */
find_and_kill_process(int other_free,int other_file,bool first)595 static int find_and_kill_process(int other_free, int other_file, bool first)
596 {
597 int i;
598 int min_score_adj = OOM_SCORE_ADJ_MAX + 1;
599 int minfree = 0;
600 int killed_size = 0;
601
602 for (i = 0; i < lowmem_targets_size; i++) {
603 minfree = lowmem_minfree[i];
604 if (other_free < minfree && other_file < minfree) {
605 min_score_adj = lowmem_adj[i];
606 break;
607 }
608 }
609
610 if (min_score_adj == OOM_SCORE_ADJ_MAX + 1)
611 return 0;
612
613 for (i = OOM_SCORE_ADJ_MAX; i >= min_score_adj; i--) {
614 struct proc *procp;
615
616 retry:
617 procp = proc_adj_lru(i);
618
619 if (procp) {
620 killed_size = kill_one_process(procp, other_free, other_file, minfree, min_score_adj, first);
621 if (killed_size < 0) {
622 goto retry;
623 } else {
624 return killed_size;
625 }
626 }
627 }
628
629 return 0;
630 }
631
mp_event(uint32_t events __unused)632 static void mp_event(uint32_t events __unused) {
633 int ret;
634 unsigned long long evcount;
635 struct sysmeminfo mi;
636 int other_free;
637 int other_file;
638 int killed_size;
639 bool first = true;
640
641 ret = read(mpevfd, &evcount, sizeof(evcount));
642 if (ret < 0)
643 ALOGE("Error reading memory pressure event fd; errno=%d",
644 errno);
645
646 if (time(NULL) - kill_lasttime < KILL_TIMEOUT)
647 return;
648
649 while (zoneinfo_parse(&mi) < 0) {
650 // Failed to read /proc/zoneinfo, assume ENOMEM and kill something
651 find_and_kill_process(0, 0, true);
652 }
653
654 other_free = mi.nr_free_pages - mi.totalreserve_pages;
655 other_file = mi.nr_file_pages - mi.nr_shmem;
656
657 do {
658 killed_size = find_and_kill_process(other_free, other_file, first);
659 if (killed_size > 0) {
660 first = false;
661 other_free += killed_size;
662 other_file += killed_size;
663 }
664 } while (killed_size > 0);
665 }
666
init_mp(char * levelstr,void * event_handler)667 static int init_mp(char *levelstr, void *event_handler)
668 {
669 int mpfd;
670 int evfd;
671 int evctlfd;
672 char buf[256];
673 struct epoll_event epev;
674 int ret;
675
676 mpfd = open(MEMCG_SYSFS_PATH "memory.pressure_level", O_RDONLY | O_CLOEXEC);
677 if (mpfd < 0) {
678 ALOGI("No kernel memory.pressure_level support (errno=%d)", errno);
679 goto err_open_mpfd;
680 }
681
682 evctlfd = open(MEMCG_SYSFS_PATH "cgroup.event_control", O_WRONLY | O_CLOEXEC);
683 if (evctlfd < 0) {
684 ALOGI("No kernel memory cgroup event control (errno=%d)", errno);
685 goto err_open_evctlfd;
686 }
687
688 evfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
689 if (evfd < 0) {
690 ALOGE("eventfd failed for level %s; errno=%d", levelstr, errno);
691 goto err_eventfd;
692 }
693
694 ret = snprintf(buf, sizeof(buf), "%d %d %s", evfd, mpfd, levelstr);
695 if (ret >= (ssize_t)sizeof(buf)) {
696 ALOGE("cgroup.event_control line overflow for level %s", levelstr);
697 goto err;
698 }
699
700 ret = write(evctlfd, buf, strlen(buf) + 1);
701 if (ret == -1) {
702 ALOGE("cgroup.event_control write failed for level %s; errno=%d",
703 levelstr, errno);
704 goto err;
705 }
706
707 epev.events = EPOLLIN;
708 epev.data.ptr = event_handler;
709 ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, evfd, &epev);
710 if (ret == -1) {
711 ALOGE("epoll_ctl for level %s failed; errno=%d", levelstr, errno);
712 goto err;
713 }
714 maxevents++;
715 mpevfd = evfd;
716 return 0;
717
718 err:
719 close(evfd);
720 err_eventfd:
721 close(evctlfd);
722 err_open_evctlfd:
723 close(mpfd);
724 err_open_mpfd:
725 return -1;
726 }
727
init(void)728 static int init(void) {
729 struct epoll_event epev;
730 int i;
731 int ret;
732
733 page_k = sysconf(_SC_PAGESIZE);
734 if (page_k == -1)
735 page_k = PAGE_SIZE;
736 page_k /= 1024;
737
738 epollfd = epoll_create(MAX_EPOLL_EVENTS);
739 if (epollfd == -1) {
740 ALOGE("epoll_create failed (errno=%d)", errno);
741 return -1;
742 }
743
744 ctrl_lfd = android_get_control_socket("lmkd");
745 if (ctrl_lfd < 0) {
746 ALOGE("get lmkd control socket failed");
747 return -1;
748 }
749
750 ret = listen(ctrl_lfd, 1);
751 if (ret < 0) {
752 ALOGE("lmkd control socket listen failed (errno=%d)", errno);
753 return -1;
754 }
755
756 epev.events = EPOLLIN;
757 epev.data.ptr = (void *)ctrl_connect_handler;
758 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, ctrl_lfd, &epev) == -1) {
759 ALOGE("epoll_ctl for lmkd control socket failed (errno=%d)", errno);
760 return -1;
761 }
762 maxevents++;
763
764 use_inkernel_interface = !access(INKERNEL_MINFREE_PATH, W_OK);
765
766 if (use_inkernel_interface) {
767 ALOGI("Using in-kernel low memory killer interface");
768 } else {
769 ret = init_mp(MEMPRESSURE_WATCH_LEVEL, (void *)&mp_event);
770 if (ret)
771 ALOGE("Kernel does not support memory pressure events or in-kernel low memory killer");
772 }
773
774 for (i = 0; i <= ADJTOSLOT(OOM_SCORE_ADJ_MAX); i++) {
775 procadjslot_list[i].next = &procadjslot_list[i];
776 procadjslot_list[i].prev = &procadjslot_list[i];
777 }
778
779 return 0;
780 }
781
mainloop(void)782 static void mainloop(void) {
783 while (1) {
784 struct epoll_event events[maxevents];
785 int nevents;
786 int i;
787
788 ctrl_dfd_reopened = 0;
789 nevents = epoll_wait(epollfd, events, maxevents, -1);
790
791 if (nevents == -1) {
792 if (errno == EINTR)
793 continue;
794 ALOGE("epoll_wait failed (errno=%d)", errno);
795 continue;
796 }
797
798 for (i = 0; i < nevents; ++i) {
799 if (events[i].events & EPOLLERR)
800 ALOGD("EPOLLERR on event #%d", i);
801 if (events[i].data.ptr)
802 (*(void (*)(uint32_t))events[i].data.ptr)(events[i].events);
803 }
804 }
805 }
806
main(int argc __unused,char ** argv __unused)807 int main(int argc __unused, char **argv __unused) {
808 struct sched_param param = {
809 .sched_priority = 1,
810 };
811
812 mlockall(MCL_FUTURE);
813 sched_setscheduler(0, SCHED_FIFO, ¶m);
814 if (!init())
815 mainloop();
816
817 ALOGI("exiting");
818 return 0;
819 }
820