On 2018/09/05 22:40, Michal Hocko wrote:
> Changelog said
>
> "Although this is possible in principle let's wait for it to actually
> happen in real life before we make the locking more complex again."
>
> So what is the real life workload that hits it? The log you have pasted
> below doesn't tell much.
Nothing special. I just ran a multi-threaded memory eater on a CONFIG_PREEMPT=y kernel.
The OOM reaper succeeded to reclaim all memory but the OOM killer still triggered
just because somebody was inside that race window.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <poll.h>
#include <sched.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <sys/mman.h>
static int memory_eater(void *unused)
{
const int fd = open("/proc/self/exe", O_RDONLY);
static cpu_set_t set = { { 1 } };
sched_setaffinity(0, sizeof(set), &set);
srand(getpid());
while (1) {
int size = rand() % 1048576;
void *ptr = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
munmap(ptr, size);
}
return 0;
}
static int child(void *unused)
{
static char *stack[256] = { };
char buf[32] = { };
int i;
sleep(1);
snprintf(buf, sizeof(buf), "tgid=%u", getpid());
prctl(PR_SET_NAME, (unsigned long) buf, 0, 0, 0);
for (i = 0; i < 256; i++)
stack[i] = malloc(4096 * 2);
for (i = 1; i < 128; i++)
if (clone(memory_eater, stack[i] + 8192, CLONE_THREAD | CLONE_SIGHAND | CLONE_VM, NULL) == -1)
_exit(1);
for (; i < 254; i++)
if (clone(memory_eater, stack[i] + 8192, CLONE_VM, NULL) == -1)
_exit(1);
return 0;
}
int main(int argc, char *argv[])
{
char *stack = malloc(1048576);
char *buf = NULL;
unsigned long size;
unsigned long i;
if (clone(child, stack + 1048576, CLONE_VM, NULL) == -1)
_exit(1);
for (size = 1048576; size < 512UL * (1 << 30); size <<= 1) {
char *cp = realloc(buf, size);
if (!cp) {
size >>= 1;
break;
}
buf = cp;
}
/* Will cause OOM due to overcommit */
for (i = 0; i < size; i += 4096)
buf[i] = 0;
while (1)
pause();
return 0;
}
>
>> [ 278.147280] Out of memory: Kill process 9943 (a.out) score 919 or sacrifice child
>> [ 278.148927] Killed process 9943 (a.out) total-vm:4267252kB, anon-rss:3430056kB, file-rss:0kB, shmem-rss:0kB
>> [ 278.151586] vmtoolsd invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=0
> [...]
>> [ 278.331527] Out of memory: Kill process 8790 (firewalld) score 5 or sacrifice child
>> [ 278.333267] Killed process 8790 (firewalld) total-vm:358012kB, anon-rss:21928kB, file-rss:0kB, shmem-rss:0kB
>> [ 278.336430] oom_reaper: reaped process 8790 (firewalld), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
>
Another example from a different machine.
[ 765.523676] a.out invoked oom-killer: gfp_mask=0x6280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null), order=0, oom_score_adj=0
[ 765.528172] a.out cpuset=/ mems_allowed=0
[ 765.530603] CPU: 5 PID: 4540 Comm: a.out Tainted: G T 4.19.0-rc2+ #689
[ 765.534307] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
[ 765.538975] Call Trace:
[ 765.540920] dump_stack+0x85/0xcb
[ 765.543088] dump_header+0x69/0x2fe
[ 765.545375] ? _raw_spin_unlock_irqrestore+0x41/0x70
[ 765.547983] oom_kill_process+0x307/0x390
[ 765.550394] out_of_memory+0x2f5/0x5b0
[ 765.552818] __alloc_pages_slowpath+0xc01/0x1030
[ 765.555442] __alloc_pages_nodemask+0x333/0x390
[ 765.557966] alloc_pages_vma+0x77/0x1f0
[ 765.560292] __handle_mm_fault+0x81c/0xf40
[ 765.562736] handle_mm_fault+0x1b7/0x3c0
[ 765.565038] __do_page_fault+0x2a6/0x580
[ 765.567420] do_page_fault+0x32/0x270
[ 765.569670] ? page_fault+0x8/0x30
[ 765.571833] page_fault+0x1e/0x30
[ 765.573934] RIP: 0033:0x4008d8
[ 765.575924] Code: Bad RIP value.
[ 765.577842] RSP: 002b:00007ffec6f7d420 EFLAGS: 00010206
[ 765.580221] RAX: 00007f6a201f4010 RBX: 0000000100000000 RCX: 0000000000000000
[ 765.583253] RDX: 00000000bde23000 RSI: 0000000000020000 RDI: 0000000200000050
[ 765.586207] RBP: 00007f6a201f4010 R08: 0000000200001000 R09: 0000000000021000
[ 765.589047] R10: 0000000000000022 R11: 0000000000001000 R12: 0000000000000006
[ 765.591996] R13: 00007ffec6f7d510 R14: 0000000000000000 R15: 0000000000000000
[ 765.595732] Mem-Info:
[ 765.597580] active_anon:794622 inactive_anon:2126 isolated_anon:0
[ 765.597580] active_file:7 inactive_file:11 isolated_file:0
[ 765.597580] unevictable:0 dirty:0 writeback:0 unstable:0
[ 765.597580] slab_reclaimable:7612 slab_unreclaimable:22840
[ 765.597580] mapped:1432 shmem:2280 pagetables:3230 bounce:0
[ 765.597580] free:20847 free_pcp:0 free_cma:0
[ 765.611408] Node 0 active_anon:3178488kB inactive_anon:8504kB active_file:28kB inactive_file:44kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:5728kB dirty:0kB writeback:0kB shmem:9120kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 3004416kB writeback_tmp:0kB unstable:0kB all_unreclaimable? yes
[ 765.620811] Node 0 DMA free:13792kB min:308kB low:384kB high:460kB active_anon:2016kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15960kB managed:15876kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 765.630835] lowmem_reserve[]: 0 2674 3378 3378
[ 765.633372] Node 0 DMA32 free:55732kB min:53260kB low:66572kB high:79884kB active_anon:2680196kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:3129152kB managed:2738556kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 765.643494] lowmem_reserve[]: 0 0 703 703
[ 765.645712] Node 0 Normal free:13912kB min:14012kB low:17512kB high:21012kB active_anon:495920kB inactive_anon:8504kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:1048576kB managed:720644kB mlocked:0kB kernel_stack:6144kB pagetables:12924kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 765.656802] lowmem_reserve[]: 0 0 0 0
[ 765.658884] Node 0 DMA: 0*4kB 0*8kB 0*16kB 1*32kB (U) 1*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 0*2048kB 3*4096kB (M) = 13792kB
[ 765.663518] Node 0 DMA32: 22*4kB (U) 26*8kB (UM) 50*16kB (U) 55*32kB (U) 46*64kB (U) 34*128kB (UM) 33*256kB (UM) 21*512kB (UM) 12*1024kB (UM) 3*2048kB (UM) 2*4096kB (M) = 55976kB
[ 765.671041] Node 0 Normal: 74*4kB (UM) 22*8kB (UM) 22*16kB (UM) 147*32kB (UE) 31*64kB (UME) 8*128kB (UME) 3*256kB (UME) 1*512kB (M) 4*1024kB (UM) 0*2048kB 0*4096kB = 13912kB
[ 765.677850] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[ 765.681352] 2295 total pagecache pages
[ 765.683550] 0 pages in swap cache
[ 765.685731] Swap cache stats: add 0, delete 0, find 0/0
[ 765.688430] Free swap = 0kB
[ 765.690419] Total swap = 0kB
[ 765.692375] 1048422 pages RAM
[ 765.694388] 0 pages HighMem/MovableOnly
[ 765.696637] 179653 pages reserved
[ 765.698618] 0 pages cma reserved
[ 765.700601] 0 pages hwpoisoned
[ 765.702651] Out of memory: Kill process 4540 (a.out) score 897 or sacrifice child
[ 765.706876] Killed process 4540 (a.out) total-vm:4267252kB, anon-rss:3111084kB, file-rss:0kB, shmem-rss:0kB
[ 765.711735] in:imjournal invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=0
[ 765.719957] in:imjournal cpuset=/ mems_allowed=0
[ 765.723302] CPU: 6 PID: 1012 Comm: in:imjournal Tainted: G T 4.19.0-rc2+ #689
[ 765.731014] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
[ 765.747405] Call Trace:
[ 765.749579] dump_stack+0x85/0xcb
[ 765.752179] dump_header+0x69/0x2fe
[ 765.754475] ? _raw_spin_unlock_irqrestore+0x41/0x70
[ 765.757307] oom_kill_process+0x307/0x390
[ 765.759873] out_of_memory+0x2f5/0x5b0
[ 765.762464] __alloc_pages_slowpath+0xc01/0x1030
[ 765.765176] __alloc_pages_nodemask+0x333/0x390
[ 765.767832] filemap_fault+0x465/0x910
[ 765.770399] ? xfs_ilock+0xbf/0x2b0 [xfs]
[ 765.770514] oom_reaper: reaped process 4540 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 765.773047] ? __xfs_filemap_fault+0x7d/0x2c0 [xfs]
[ 765.773054] ? down_read_nested+0x66/0xa0
[ 765.783474] __xfs_filemap_fault+0x8e/0x2c0 [xfs]
[ 765.786436] __do_fault+0x11/0x133
[ 765.788649] __handle_mm_fault+0xa57/0xf40
[ 765.791022] handle_mm_fault+0x1b7/0x3c0
[ 765.793307] __do_page_fault+0x2a6/0x580
[ 765.795566] do_page_fault+0x32/0x270
[ 765.797708] ? page_fault+0x8/0x30
[ 765.799735] page_fault+0x1e/0x30
[ 765.801707] RIP: 0033:0x7f9a91e00fcf
[ 765.803724] Code: Bad RIP value.
[ 765.805569] RSP: 002b:00007f9a8ebe6c60 EFLAGS: 00010293
[ 765.808021] RAX: 0000000000000000 RBX: 0000562b41445bb0 RCX: 00007f9a91e00fcf
[ 765.810969] RDX: 00007f9a8ebe6c80 RSI: 0000000000000001 RDI: 00007f9a8ebe6ca0
[ 765.813911] RBP: 00000000000dbba0 R08: 0000000000000008 R09: 0000000000000000
[ 765.816861] R10: 0000000000000000 R11: 0000000000000293 R12: 00007f9a8ebe6d90
[ 765.819762] R13: 00007f9a80029af0 R14: 00007f9a8002fdf0 R15: 00007f9a8001ea60
[ 765.823619] Mem-Info:
[ 765.825340] active_anon:16863 inactive_anon:2126 isolated_anon:0
[ 765.825340] active_file:35 inactive_file:3002 isolated_file:0
[ 765.825340] unevictable:0 dirty:0 writeback:0 unstable:0
[ 765.825340] slab_reclaimable:7612 slab_unreclaimable:22764
[ 765.825340] mapped:2597 shmem:2280 pagetables:1686 bounce:0
[ 765.825340] free:796988 free_pcp:423 free_cma:0
[ 765.839674] Node 0 active_anon:67452kB inactive_anon:8504kB active_file:140kB inactive_file:12008kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:10388kB dirty:0kB writeback:0kB shmem:9120kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 24576kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
[ 765.848867] Node 0 DMA free:15840kB min:308kB low:384kB high:460kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15960kB managed:15876kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 765.859189] lowmem_reserve[]: 0 2674 3378 3378
[ 765.861638] Node 0 DMA32 free:2735512kB min:53260kB low:66572kB high:79884kB active_anon:12kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:3129152kB managed:2738556kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:1276kB local_pcp:0kB free_cma:0kB
[ 765.871163] lowmem_reserve[]: 0 0 703 703
[ 765.873345] Node 0 Normal free:436320kB min:14012kB low:17512kB high:21012kB active_anon:67460kB inactive_anon:8504kB active_file:140kB inactive_file:12112kB unevictable:0kB writepending:0kB present:1048576kB managed:720644kB mlocked:0kB kernel_stack:6128kB pagetables:6844kB bounce:0kB free_pcp:416kB local_pcp:0kB free_cma:0kB
[ 765.884108] lowmem_reserve[]: 0 0 0 0
[ 765.886080] Node 0 DMA: 1*4kB (U) 0*8kB 0*16kB 1*32kB (U) 1*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15844kB
[ 765.891129] Node 0 DMA32: 28*4kB (UM) 33*8kB (UM) 58*16kB (UM) 60*32kB (UM) 48*64kB (UM) 34*128kB (UM) 34*256kB (UM) 21*512kB (UM) 12*1024kB (UM) 9*2048kB (UM) 653*4096kB (M) = 2735512kB
[ 765.898614] Node 0 Normal: 3528*4kB (UM) 1178*8kB (UM) 1371*16kB (UM) 898*32kB (UME) 362*64kB (UME) 108*128kB (UME) 46*256kB (UME) 22*512kB (M) 7*1024kB (UM) 10*2048kB (M) 67*4096kB (M) = 436320kB
[ 765.906220] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[ 765.909852] 5357 total pagecache pages
[ 765.912036] 0 pages in swap cache
[ 765.914092] Swap cache stats: add 0, delete 0, find 0/0
[ 765.916680] Free swap = 0kB
[ 765.918560] Total swap = 0kB
[ 765.920583] 1048422 pages RAM
[ 765.922676] 0 pages HighMem/MovableOnly
[ 765.924973] 179653 pages reserved
[ 765.927004] 0 pages cma reserved
[ 765.928919] 0 pages hwpoisoned
[ 765.930821] Unreclaimable slab info:
[ 765.932934] Name Used Total
[ 765.936489] nf_conntrack 0KB 31KB
[ 765.939582] xfs_buf 22KB 127KB
[ 765.942322] xfs_ili 20KB 127KB
[ 765.944942] xfs_efi_item 0KB 31KB
[ 765.947427] xfs_efd_item 0KB 31KB
[ 765.949957] xfs_buf_item 0KB 62KB
[ 765.952490] xfs_trans 0KB 63KB
[ 765.955268] xfs_ifork 27KB 158KB
[ 765.957913] xfs_da_state 0KB 31KB
[ 765.960483] xfs_btree_cur 0KB 63KB
[ 765.962943] xfs_bmap_free_item 0KB 15KB
[ 765.965415] xfs_log_ticket 0KB 63KB
[ 765.967880] bio-2 24KB 63KB
[ 765.970409] sd_ext_cdb 0KB 15KB
[ 765.973778] scsi_sense_cache 7KB 128KB
[ 765.976603] fib6_nodes 11KB 32KB
[ 765.979072] ip6_dst_cache 4KB 31KB
[ 765.981504] RAWv6 266KB 384KB
[ 765.983897] UDPv6 0KB 31KB
[ 765.986243] TCPv6 10KB 30KB
[ 765.988850] sgpool-128 8KB 62KB
[ 765.991320] sgpool-64 4KB 31KB
[ 765.993554] sgpool-32 2KB 31KB
[ 765.995733] sgpool-16 1KB 31KB
[ 765.997852] sgpool-8 1KB 63KB
[ 766.000043] mqueue_inode_cache 1KB 31KB
[ 766.002313] bio-1 2KB 31KB
[ 766.004549] fasync_cache 0KB 15KB
[ 766.006757] posix_timers_cache 0KB 31KB
[ 766.009787] UNIX 187KB 240KB
[ 766.012175] tcp_bind_bucket 1KB 32KB
[ 766.014163] ip_fib_trie 2KB 15KB
[ 766.016080] ip_fib_alias 3KB 15KB
[ 766.017988] ip_dst_cache 6KB 31KB
[ 766.019808] RAW 464KB 585KB
[ 766.021751] UDP 8KB 30KB
[ 766.023730] request_sock_TCP 0KB 31KB
[ 766.025684] TCP 12KB 31KB
[ 766.027458] hugetlbfs_inode_cache 2KB 30KB
[ 766.029314] eventpoll_pwq 37KB 63KB
[ 766.031131] eventpoll_epi 53KB 94KB
[ 766.032938] inotify_inode_mark 27KB 31KB
[ 766.034774] request_queue 16KB 56KB
[ 766.036598] blkdev_ioc 31KB 126KB
[ 766.038508] bio-0 6KB 127KB
[ 766.040390] biovec-max 405KB 506KB
[ 766.042199] biovec-128 0KB 31KB
[ 766.044857] biovec-64 0KB 94KB
[ 766.047009] biovec-16 0KB 63KB
[ 766.048856] bio_integrity_payload 1KB 31KB
[ 766.050745] khugepaged_mm_slot 1KB 15KB
[ 766.052602] uid_cache 2KB 31KB
[ 766.054537] dmaengine-unmap-2 0KB 15KB
[ 766.056523] audit_buffer 0KB 15KB
[ 766.058506] skbuff_fclone_cache 0KB 31KB
[ 766.060521] skbuff_head_cache 0KB 127KB
[ 766.062391] configfs_dir_cache 1KB 15KB
[ 766.064226] file_lock_cache 13KB 31KB
[ 766.066061] file_lock_ctx 15KB 31KB
[ 766.067883] fsnotify_mark_connector 18KB 31KB
[ 766.069874] net_namespace 0KB 32KB
[ 766.071801] shmem_inode_cache 1546KB 1595KB
[ 766.073838] task_delay_info 177KB 318KB
[ 766.075820] taskstats 2KB 63KB
[ 766.077664] proc_dir_entry 498KB 540KB
[ 766.080418] pde_opener 0KB 31KB
[ 766.082620] seq_file 1KB 127KB
[ 766.084526] sigqueue 0KB 63KB
[ 766.086374] kernfs_node_cache 29487KB 29536KB
[ 766.088403] mnt_cache 90KB 126KB
[ 766.090442] filp 1195KB 1466KB
[ 766.092412] names_cache 0KB 155KB
[ 766.094412] key_jar 4KB 31KB
[ 766.096428] nsproxy 1KB 15KB
[ 766.098448] vm_area_struct 3312KB 3480KB
[ 766.100378] mm_struct 68KB 128KB
[ 766.102292] fs_cache 90KB 189KB
[ 766.104179] files_cache 200KB 281KB
[ 766.106192] signal_cache 690KB 892KB
[ 766.108158] sighand_cache 943KB 1137KB
[ 766.110116] task_struct 3590KB 3825KB
[ 766.112005] cred_jar 249KB 378KB
[ 766.113912] anon_vma_chain 1634KB 1742KB
[ 766.116711] anon_vma 1214KB 1309KB
[ 766.119046] pid 129KB 256KB
[ 766.121108] Acpi-Operand 3713KB 3761KB
[ 766.123251] Acpi-ParseExt 0KB 15KB
[ 766.125261] Acpi-Parse 0KB 31KB
[ 766.127259] Acpi-State 0KB 47KB
[ 766.129256] Acpi-Namespace 2913KB 2936KB
[ 766.131118] numa_policy 74KB 94KB
[ 766.132954] trace_event_file 455KB 456KB
[ 766.134815] ftrace_event_field 777KB 787KB
[ 766.136762] pool_workqueue 72KB 94KB
[ 766.138859] task_group 35KB 63KB
[ 766.140890] page->ptl 725KB 828KB
[ 766.142857] dma-kmalloc-512 0KB 31KB
[ 766.144751] kmalloc-8192 441KB 499KB
[ 766.146793] kmalloc-4096 965KB 1090KB
[ 766.148619] kmalloc-2048 4570KB 4691KB
[ 766.150479] kmalloc-1024 881KB 988KB
[ 766.153265] kmalloc-512 3343KB 3430KB
[ 766.155491] kmalloc-256 3368KB 3434KB
[ 766.157383] kmalloc-192 276KB 447KB
[ 766.159287] kmalloc-128 981KB 1078KB
[ 766.161152] kmalloc-96 2288KB 2294KB
[ 766.163011] kmalloc-64 1675KB 1921KB
[ 766.164862] kmalloc-32 1395KB 1533KB
[ 766.166635] kmalloc-16 3359KB 3795KB
[ 766.168413] kmalloc-8 2344KB 2384KB
[ 766.170249] kmem_cache_node 102KB 126KB
[ 766.172232] kmem_cache 147KB 158KB
[ 766.174204] Out of memory: Kill process 679 (firewalld) score 6 or sacrifice child
[ 766.176757] Killed process 679 (firewalld) total-vm:357864kB, anon-rss:21920kB, file-rss:0kB, shmem-rss:0kB
[ 766.183011] oom_reaper: reaped process 679 (firewalld), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
