oom_kill.c revision 0aad4b3124850e85fe54e610802f0917ce46a1ae
1/* 2 * linux/mm/oom_kill.c 3 * 4 * Copyright (C) 1998,2000 Rik van Riel 5 * Thanks go out to Claus Fischer for some serious inspiration and 6 * for goading me into coding this file... 7 * 8 * The routines in this file are used to kill a process when 9 * we're seriously out of memory. This gets called from __alloc_pages() 10 * in mm/page_alloc.c when we really run out of memory. 11 * 12 * Since we won't call these routines often (on a well-configured 13 * machine) this file will double as a 'coding guide' and a signpost 14 * for newbie kernel hackers. It features several pointers to major 15 * kernel subsystems and hints as to where to find out what things do. 16 */ 17 18#include <linux/oom.h> 19#include <linux/mm.h> 20#include <linux/err.h> 21#include <linux/gfp.h> 22#include <linux/sched.h> 23#include <linux/swap.h> 24#include <linux/timex.h> 25#include <linux/jiffies.h> 26#include <linux/cpuset.h> 27#include <linux/module.h> 28#include <linux/notifier.h> 29#include <linux/memcontrol.h> 30#include <linux/mempolicy.h> 31#include <linux/security.h> 32 33int sysctl_panic_on_oom; 34int sysctl_oom_kill_allocating_task; 35int sysctl_oom_dump_tasks = 1; 36static DEFINE_SPINLOCK(zone_scan_lock); 37/* #define DEBUG */ 38 39#ifdef CONFIG_NUMA 40/** 41 * has_intersects_mems_allowed() - check task eligiblity for kill 42 * @tsk: task struct of which task to consider 43 * @mask: nodemask passed to page allocator for mempolicy ooms 44 * 45 * Task eligibility is determined by whether or not a candidate task, @tsk, 46 * shares the same mempolicy nodes as current if it is bound by such a policy 47 * and whether or not it has the same set of allowed cpuset nodes. 48 */ 49static bool has_intersects_mems_allowed(struct task_struct *tsk, 50 const nodemask_t *mask) 51{ 52 struct task_struct *start = tsk; 53 54 do { 55 if (mask) { 56 /* 57 * If this is a mempolicy constrained oom, tsk's 58 * cpuset is irrelevant. Only return true if its 59 * mempolicy intersects current, otherwise it may be 60 * needlessly killed. 61 */ 62 if (mempolicy_nodemask_intersects(tsk, mask)) 63 return true; 64 } else { 65 /* 66 * This is not a mempolicy constrained oom, so only 67 * check the mems of tsk's cpuset. 68 */ 69 if (cpuset_mems_allowed_intersects(current, tsk)) 70 return true; 71 } 72 tsk = next_thread(tsk); 73 } while (tsk != start); 74 return false; 75} 76#else 77static bool has_intersects_mems_allowed(struct task_struct *tsk, 78 const nodemask_t *mask) 79{ 80 return true; 81} 82#endif /* CONFIG_NUMA */ 83 84/* 85 * The process p may have detached its own ->mm while exiting or through 86 * use_mm(), but one or more of its subthreads may still have a valid 87 * pointer. Return p, or any of its subthreads with a valid ->mm, with 88 * task_lock() held. 89 */ 90static struct task_struct *find_lock_task_mm(struct task_struct *p) 91{ 92 struct task_struct *t = p; 93 94 do { 95 task_lock(t); 96 if (likely(t->mm)) 97 return t; 98 task_unlock(t); 99 } while_each_thread(p, t); 100 101 return NULL; 102} 103 104/** 105 * badness - calculate a numeric value for how bad this task has been 106 * @p: task struct of which task we should calculate 107 * @uptime: current uptime in seconds 108 * 109 * The formula used is relatively simple and documented inline in the 110 * function. The main rationale is that we want to select a good task 111 * to kill when we run out of memory. 112 * 113 * Good in this context means that: 114 * 1) we lose the minimum amount of work done 115 * 2) we recover a large amount of memory 116 * 3) we don't kill anything innocent of eating tons of memory 117 * 4) we want to kill the minimum amount of processes (one) 118 * 5) we try to kill the process the user expects us to kill, this 119 * algorithm has been meticulously tuned to meet the principle 120 * of least surprise ... (be careful when you change it) 121 */ 122 123unsigned long badness(struct task_struct *p, unsigned long uptime) 124{ 125 unsigned long points, cpu_time, run_time; 126 struct task_struct *child; 127 struct task_struct *c, *t; 128 int oom_adj = p->signal->oom_adj; 129 struct task_cputime task_time; 130 unsigned long utime; 131 unsigned long stime; 132 133 if (oom_adj == OOM_DISABLE) 134 return 0; 135 136 p = find_lock_task_mm(p); 137 if (!p) 138 return 0; 139 140 /* 141 * The memory size of the process is the basis for the badness. 142 */ 143 points = p->mm->total_vm; 144 task_unlock(p); 145 146 /* 147 * swapoff can easily use up all memory, so kill those first. 148 */ 149 if (p->flags & PF_OOM_ORIGIN) 150 return ULONG_MAX; 151 152 /* 153 * Processes which fork a lot of child processes are likely 154 * a good choice. We add half the vmsize of the children if they 155 * have an own mm. This prevents forking servers to flood the 156 * machine with an endless amount of children. In case a single 157 * child is eating the vast majority of memory, adding only half 158 * to the parents will make the child our kill candidate of choice. 159 */ 160 t = p; 161 do { 162 list_for_each_entry(c, &t->children, sibling) { 163 child = find_lock_task_mm(c); 164 if (child) { 165 if (child->mm != p->mm) 166 points += child->mm->total_vm/2 + 1; 167 task_unlock(child); 168 } 169 } 170 } while_each_thread(p, t); 171 172 /* 173 * CPU time is in tens of seconds and run time is in thousands 174 * of seconds. There is no particular reason for this other than 175 * that it turned out to work very well in practice. 176 */ 177 thread_group_cputime(p, &task_time); 178 utime = cputime_to_jiffies(task_time.utime); 179 stime = cputime_to_jiffies(task_time.stime); 180 cpu_time = (utime + stime) >> (SHIFT_HZ + 3); 181 182 183 if (uptime >= p->start_time.tv_sec) 184 run_time = (uptime - p->start_time.tv_sec) >> 10; 185 else 186 run_time = 0; 187 188 if (cpu_time) 189 points /= int_sqrt(cpu_time); 190 if (run_time) 191 points /= int_sqrt(int_sqrt(run_time)); 192 193 /* 194 * Niced processes are most likely less important, so double 195 * their badness points. 196 */ 197 if (task_nice(p) > 0) 198 points *= 2; 199 200 /* 201 * Superuser processes are usually more important, so we make it 202 * less likely that we kill those. 203 */ 204 if (has_capability_noaudit(p, CAP_SYS_ADMIN) || 205 has_capability_noaudit(p, CAP_SYS_RESOURCE)) 206 points /= 4; 207 208 /* 209 * We don't want to kill a process with direct hardware access. 210 * Not only could that mess up the hardware, but usually users 211 * tend to only have this flag set on applications they think 212 * of as important. 213 */ 214 if (has_capability_noaudit(p, CAP_SYS_RAWIO)) 215 points /= 4; 216 217 /* 218 * Adjust the score by oom_adj. 219 */ 220 if (oom_adj) { 221 if (oom_adj > 0) { 222 if (!points) 223 points = 1; 224 points <<= oom_adj; 225 } else 226 points >>= -(oom_adj); 227 } 228 229#ifdef DEBUG 230 printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", 231 p->pid, p->comm, points); 232#endif 233 return points; 234} 235 236/* 237 * Determine the type of allocation constraint. 238 */ 239#ifdef CONFIG_NUMA 240static enum oom_constraint constrained_alloc(struct zonelist *zonelist, 241 gfp_t gfp_mask, nodemask_t *nodemask) 242{ 243 struct zone *zone; 244 struct zoneref *z; 245 enum zone_type high_zoneidx = gfp_zone(gfp_mask); 246 247 /* 248 * Reach here only when __GFP_NOFAIL is used. So, we should avoid 249 * to kill current.We have to random task kill in this case. 250 * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now. 251 */ 252 if (gfp_mask & __GFP_THISNODE) 253 return CONSTRAINT_NONE; 254 255 /* 256 * The nodemask here is a nodemask passed to alloc_pages(). Now, 257 * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy 258 * feature. mempolicy is an only user of nodemask here. 259 * check mempolicy's nodemask contains all N_HIGH_MEMORY 260 */ 261 if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) 262 return CONSTRAINT_MEMORY_POLICY; 263 264 /* Check this allocation failure is caused by cpuset's wall function */ 265 for_each_zone_zonelist_nodemask(zone, z, zonelist, 266 high_zoneidx, nodemask) 267 if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) 268 return CONSTRAINT_CPUSET; 269 270 return CONSTRAINT_NONE; 271} 272#else 273static enum oom_constraint constrained_alloc(struct zonelist *zonelist, 274 gfp_t gfp_mask, nodemask_t *nodemask) 275{ 276 return CONSTRAINT_NONE; 277} 278#endif 279 280/* 281 * Simple selection loop. We chose the process with the highest 282 * number of 'points'. We expect the caller will lock the tasklist. 283 * 284 * (not docbooked, we don't want this one cluttering up the manual) 285 */ 286static struct task_struct *select_bad_process(unsigned long *ppoints, 287 struct mem_cgroup *mem, const nodemask_t *nodemask) 288{ 289 struct task_struct *p; 290 struct task_struct *chosen = NULL; 291 struct timespec uptime; 292 *ppoints = 0; 293 294 do_posix_clock_monotonic_gettime(&uptime); 295 for_each_process(p) { 296 unsigned long points; 297 298 /* skip the init task and kthreads */ 299 if (is_global_init(p) || (p->flags & PF_KTHREAD)) 300 continue; 301 if (mem && !task_in_mem_cgroup(p, mem)) 302 continue; 303 if (!has_intersects_mems_allowed(p, nodemask)) 304 continue; 305 306 /* 307 * This task already has access to memory reserves and is 308 * being killed. Don't allow any other task access to the 309 * memory reserve. 310 * 311 * Note: this may have a chance of deadlock if it gets 312 * blocked waiting for another task which itself is waiting 313 * for memory. Is there a better alternative? 314 */ 315 if (test_tsk_thread_flag(p, TIF_MEMDIE)) 316 return ERR_PTR(-1UL); 317 318 /* 319 * This is in the process of releasing memory so wait for it 320 * to finish before killing some other task by mistake. 321 * 322 * However, if p is the current task, we allow the 'kill' to 323 * go ahead if it is exiting: this will simply set TIF_MEMDIE, 324 * which will allow it to gain access to memory reserves in 325 * the process of exiting and releasing its resources. 326 * Otherwise we could get an easy OOM deadlock. 327 */ 328 if ((p->flags & PF_EXITING) && p->mm) { 329 if (p != current) 330 return ERR_PTR(-1UL); 331 332 chosen = p; 333 *ppoints = ULONG_MAX; 334 } 335 336 if (p->signal->oom_adj == OOM_DISABLE) 337 continue; 338 339 points = badness(p, uptime.tv_sec); 340 if (points > *ppoints || !chosen) { 341 chosen = p; 342 *ppoints = points; 343 } 344 } 345 346 return chosen; 347} 348 349/** 350 * dump_tasks - dump current memory state of all system tasks 351 * @mem: current's memory controller, if constrained 352 * 353 * Dumps the current memory state of all system tasks, excluding kernel threads. 354 * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj 355 * score, and name. 356 * 357 * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are 358 * shown. 359 * 360 * Call with tasklist_lock read-locked. 361 */ 362static void dump_tasks(const struct mem_cgroup *mem) 363{ 364 struct task_struct *p; 365 struct task_struct *task; 366 367 printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj " 368 "name\n"); 369 for_each_process(p) { 370 if (p->flags & PF_KTHREAD) 371 continue; 372 if (mem && !task_in_mem_cgroup(p, mem)) 373 continue; 374 375 task = find_lock_task_mm(p); 376 if (!task) { 377 /* 378 * This is a kthread or all of p's threads have already 379 * detached their mm's. There's no need to report 380 * them; they can't be oom killed anyway. 381 */ 382 continue; 383 } 384 385 printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3u %3d %s\n", 386 task->pid, __task_cred(task)->uid, task->tgid, 387 task->mm->total_vm, get_mm_rss(task->mm), 388 task_cpu(task), task->signal->oom_adj, task->comm); 389 task_unlock(task); 390 } 391} 392 393static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, 394 struct mem_cgroup *mem) 395{ 396 task_lock(current); 397 pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " 398 "oom_adj=%d\n", 399 current->comm, gfp_mask, order, current->signal->oom_adj); 400 cpuset_print_task_mems_allowed(current); 401 task_unlock(current); 402 dump_stack(); 403 mem_cgroup_print_oom_info(mem, p); 404 show_mem(); 405 if (sysctl_oom_dump_tasks) 406 dump_tasks(mem); 407} 408 409#define K(x) ((x) << (PAGE_SHIFT-10)) 410static int oom_kill_task(struct task_struct *p) 411{ 412 p = find_lock_task_mm(p); 413 if (!p || p->signal->oom_adj == OOM_DISABLE) { 414 task_unlock(p); 415 return 1; 416 } 417 pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", 418 task_pid_nr(p), p->comm, K(p->mm->total_vm), 419 K(get_mm_counter(p->mm, MM_ANONPAGES)), 420 K(get_mm_counter(p->mm, MM_FILEPAGES))); 421 task_unlock(p); 422 423 p->rt.time_slice = HZ; 424 set_tsk_thread_flag(p, TIF_MEMDIE); 425 force_sig(SIGKILL, p); 426 return 0; 427} 428#undef K 429 430static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, 431 unsigned long points, struct mem_cgroup *mem, 432 const char *message) 433{ 434 struct task_struct *victim = p; 435 struct task_struct *child; 436 struct task_struct *t = p; 437 unsigned long victim_points = 0; 438 struct timespec uptime; 439 440 if (printk_ratelimit()) 441 dump_header(p, gfp_mask, order, mem); 442 443 /* 444 * If the task is already exiting, don't alarm the sysadmin or kill 445 * its children or threads, just set TIF_MEMDIE so it can die quickly 446 */ 447 if (p->flags & PF_EXITING) { 448 set_tsk_thread_flag(p, TIF_MEMDIE); 449 return 0; 450 } 451 452 task_lock(p); 453 pr_err("%s: Kill process %d (%s) score %lu or sacrifice child\n", 454 message, task_pid_nr(p), p->comm, points); 455 task_unlock(p); 456 457 /* 458 * If any of p's children has a different mm and is eligible for kill, 459 * the one with the highest badness() score is sacrificed for its 460 * parent. This attempts to lose the minimal amount of work done while 461 * still freeing memory. 462 */ 463 do_posix_clock_monotonic_gettime(&uptime); 464 do { 465 list_for_each_entry(child, &t->children, sibling) { 466 unsigned long child_points; 467 468 if (child->mm == p->mm) 469 continue; 470 if (mem && !task_in_mem_cgroup(child, mem)) 471 continue; 472 473 /* badness() returns 0 if the thread is unkillable */ 474 child_points = badness(child, uptime.tv_sec); 475 if (child_points > victim_points) { 476 victim = child; 477 victim_points = child_points; 478 } 479 } 480 } while_each_thread(p, t); 481 482 return oom_kill_task(victim); 483} 484 485/* 486 * Determines whether the kernel must panic because of the panic_on_oom sysctl. 487 */ 488static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, 489 int order) 490{ 491 if (likely(!sysctl_panic_on_oom)) 492 return; 493 if (sysctl_panic_on_oom != 2) { 494 /* 495 * panic_on_oom == 1 only affects CONSTRAINT_NONE, the kernel 496 * does not panic for cpuset, mempolicy, or memcg allocation 497 * failures. 498 */ 499 if (constraint != CONSTRAINT_NONE) 500 return; 501 } 502 read_lock(&tasklist_lock); 503 dump_header(NULL, gfp_mask, order, NULL); 504 read_unlock(&tasklist_lock); 505 panic("Out of memory: %s panic_on_oom is enabled\n", 506 sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); 507} 508 509#ifdef CONFIG_CGROUP_MEM_RES_CTLR 510void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) 511{ 512 unsigned long points = 0; 513 struct task_struct *p; 514 515 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0); 516 read_lock(&tasklist_lock); 517retry: 518 p = select_bad_process(&points, mem, NULL); 519 if (!p || PTR_ERR(p) == -1UL) 520 goto out; 521 522 if (oom_kill_process(p, gfp_mask, 0, points, mem, 523 "Memory cgroup out of memory")) 524 goto retry; 525out: 526 read_unlock(&tasklist_lock); 527} 528#endif 529 530static BLOCKING_NOTIFIER_HEAD(oom_notify_list); 531 532int register_oom_notifier(struct notifier_block *nb) 533{ 534 return blocking_notifier_chain_register(&oom_notify_list, nb); 535} 536EXPORT_SYMBOL_GPL(register_oom_notifier); 537 538int unregister_oom_notifier(struct notifier_block *nb) 539{ 540 return blocking_notifier_chain_unregister(&oom_notify_list, nb); 541} 542EXPORT_SYMBOL_GPL(unregister_oom_notifier); 543 544/* 545 * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero 546 * if a parallel OOM killing is already taking place that includes a zone in 547 * the zonelist. Otherwise, locks all zones in the zonelist and returns 1. 548 */ 549int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) 550{ 551 struct zoneref *z; 552 struct zone *zone; 553 int ret = 1; 554 555 spin_lock(&zone_scan_lock); 556 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { 557 if (zone_is_oom_locked(zone)) { 558 ret = 0; 559 goto out; 560 } 561 } 562 563 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { 564 /* 565 * Lock each zone in the zonelist under zone_scan_lock so a 566 * parallel invocation of try_set_zonelist_oom() doesn't succeed 567 * when it shouldn't. 568 */ 569 zone_set_flag(zone, ZONE_OOM_LOCKED); 570 } 571 572out: 573 spin_unlock(&zone_scan_lock); 574 return ret; 575} 576 577/* 578 * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed 579 * allocation attempts with zonelists containing them may now recall the OOM 580 * killer, if necessary. 581 */ 582void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) 583{ 584 struct zoneref *z; 585 struct zone *zone; 586 587 spin_lock(&zone_scan_lock); 588 for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) { 589 zone_clear_flag(zone, ZONE_OOM_LOCKED); 590 } 591 spin_unlock(&zone_scan_lock); 592} 593 594/* 595 * Try to acquire the oom killer lock for all system zones. Returns zero if a 596 * parallel oom killing is taking place, otherwise locks all zones and returns 597 * non-zero. 598 */ 599static int try_set_system_oom(void) 600{ 601 struct zone *zone; 602 int ret = 1; 603 604 spin_lock(&zone_scan_lock); 605 for_each_populated_zone(zone) 606 if (zone_is_oom_locked(zone)) { 607 ret = 0; 608 goto out; 609 } 610 for_each_populated_zone(zone) 611 zone_set_flag(zone, ZONE_OOM_LOCKED); 612out: 613 spin_unlock(&zone_scan_lock); 614 return ret; 615} 616 617/* 618 * Clears ZONE_OOM_LOCKED for all system zones so that failed allocation 619 * attempts or page faults may now recall the oom killer, if necessary. 620 */ 621static void clear_system_oom(void) 622{ 623 struct zone *zone; 624 625 spin_lock(&zone_scan_lock); 626 for_each_populated_zone(zone) 627 zone_clear_flag(zone, ZONE_OOM_LOCKED); 628 spin_unlock(&zone_scan_lock); 629} 630 631/** 632 * out_of_memory - kill the "best" process when we run out of memory 633 * @zonelist: zonelist pointer 634 * @gfp_mask: memory allocation flags 635 * @order: amount of memory being requested as a power of 2 636 * @nodemask: nodemask passed to page allocator 637 * 638 * If we run out of memory, we have the choice between either 639 * killing a random task (bad), letting the system crash (worse) 640 * OR try to be smart about which process to kill. Note that we 641 * don't have to be perfect here, we just have to be good. 642 */ 643void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, 644 int order, nodemask_t *nodemask) 645{ 646 struct task_struct *p; 647 unsigned long freed = 0; 648 unsigned long points; 649 enum oom_constraint constraint = CONSTRAINT_NONE; 650 651 blocking_notifier_call_chain(&oom_notify_list, 0, &freed); 652 if (freed > 0) 653 /* Got some memory back in the last second. */ 654 return; 655 656 /* 657 * If current has a pending SIGKILL, then automatically select it. The 658 * goal is to allow it to allocate so that it may quickly exit and free 659 * its memory. 660 */ 661 if (fatal_signal_pending(current)) { 662 set_thread_flag(TIF_MEMDIE); 663 return; 664 } 665 666 /* 667 * Check if there were limitations on the allocation (only relevant for 668 * NUMA) that may require different handling. 669 */ 670 if (zonelist) 671 constraint = constrained_alloc(zonelist, gfp_mask, nodemask); 672 check_panic_on_oom(constraint, gfp_mask, order); 673 674 read_lock(&tasklist_lock); 675 if (sysctl_oom_kill_allocating_task) { 676 /* 677 * oom_kill_process() needs tasklist_lock held. If it returns 678 * non-zero, current could not be killed so we must fallback to 679 * the tasklist scan. 680 */ 681 if (!oom_kill_process(current, gfp_mask, order, 0, NULL, 682 "Out of memory (oom_kill_allocating_task)")) 683 return; 684 } 685 686retry: 687 p = select_bad_process(&points, NULL, 688 constraint == CONSTRAINT_MEMORY_POLICY ? nodemask : 689 NULL); 690 if (PTR_ERR(p) == -1UL) 691 return; 692 693 /* Found nothing?!?! Either we hang forever, or we panic. */ 694 if (!p) { 695 dump_header(NULL, gfp_mask, order, NULL); 696 read_unlock(&tasklist_lock); 697 panic("Out of memory and no killable processes...\n"); 698 } 699 700 if (oom_kill_process(p, gfp_mask, order, points, NULL, 701 "Out of memory")) 702 goto retry; 703 read_unlock(&tasklist_lock); 704 705 /* 706 * Give "p" a good chance of killing itself before we 707 * retry to allocate memory unless "p" is current 708 */ 709 if (!test_thread_flag(TIF_MEMDIE)) 710 schedule_timeout_uninterruptible(1); 711} 712 713/* 714 * The pagefault handler calls here because it is out of memory, so kill a 715 * memory-hogging task. If a populated zone has ZONE_OOM_LOCKED set, a parallel 716 * oom killing is already in progress so do nothing. If a task is found with 717 * TIF_MEMDIE set, it has been killed so do nothing and allow it to exit. 718 */ 719void pagefault_out_of_memory(void) 720{ 721 if (try_set_system_oom()) { 722 out_of_memory(NULL, 0, 0, NULL); 723 clear_system_oom(); 724 } 725 if (!test_thread_flag(TIF_MEMDIE)) 726 schedule_timeout_uninterruptible(1); 727} 728