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418 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Yi Wang
|
f364f06b34 |
mm/oom_kill.c: fix oom_cpuset_eligible() comment
Commit
|
||
Edward Chron
|
70cb6d2677 |
mm/oom: add oom_score_adj and pgtables to Killed process message
For an OOM event: print oom_score_adj value for the OOM Killed process to document what the oom score adjust value was at the time the process was OOM Killed. The adjustment value can be set by user code and it affects the resulting oom_score so it is used to influence kill process selection. When eligible tasks are not printed (sysctl oom_dump_tasks = 0) printing this value is the only documentation of the value for the process being killed. Having this value on the Killed process message is useful to document if a miscconfiguration occurred or to confirm that the oom_score_adj configuration applies as expected. An example which illustates both misconfiguration and validation that the oom_score_adj was applied as expected is: Aug 14 23:00:02 testserver kernel: Out of memory: Killed process 2692 (systemd-udevd) total-vm:1056800kB, anon-rss:1052760kB, file-rss:4kB, shmem-rss:0kB pgtables:22kB oom_score_adj:1000 The systemd-udevd is a critical system application that should have an oom_score_adj of -1000. It was miconfigured to have a adjustment of 1000 making it a highly favored OOM kill target process. The output documents both the misconfiguration and the fact that the process was correctly targeted by OOM due to the miconfiguration. This can be quite helpful for triage and problem determination. The addition of the pgtables_bytes shows page table usage by the process and is a useful measure of the memory size of the process. Link: http://lkml.kernel.org/r/20190822173157.1569-1-echron@arista.com Signed-off-by: Edward Chron <echron@arista.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
|
f9c645621a |
memcg, oom: don't require __GFP_FS when invoking memcg OOM killer
Masoud Sharbiani noticed that commit |
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Joel Savitz
|
8ac3f8fe91 |
mm/oom_kill.c: add task UID to info message on an oom kill
In the event of an oom kill, useful information about the killed process is printed to dmesg. Users, especially system administrators, will find it useful to immediately see the UID of the process. We already print uid when dumping eligible tasks so it is not overly hard to find that information in the oom report. However this information is unavailable when dumping of eligible tasks is disabled. In the following example, abuse_the_ram is the name of a program that attempts to iteratively allocate all available memory until it is stopped by force. Current message: Out of memory: Killed process 35389 (abuse_the_ram) total-vm:133718232kB, anon-rss:129624980kB, file-rss:0kB, shmem-rss:0kB Patched message: Out of memory: Killed process 2739 (abuse_the_ram), total-vm:133880028kB, anon-rss:129754836kB, file-rss:0kB, shmem-rss:0kB, UID:0 [akpm@linux-foundation.org: s/UID %d/UID:%u/ in printk] Link: http://lkml.kernel.org/r/1560362273-534-1-git-send-email-jsavitz@redhat.com Signed-off-by: Joel Savitz <jsavitz@redhat.com> Suggested-by: David Rientjes <rientjes@google.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
|
2c207985f3 |
mm/oom_kill.c: remove redundant OOM score normalization in select_bad_process()
Since commit
|
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Shakeel Butt
|
ac311a14c6 |
oom: decouple mems_allowed from oom_unkillable_task
Commit |
||
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Shakeel Butt
|
6ba749ee78 |
mm, oom: remove redundant task_in_mem_cgroup() check
oom_unkillable_task() can be called from three different contexts i.e. global OOM, memcg OOM and oom_score procfs interface. At the moment oom_unkillable_task() does a task_in_mem_cgroup() check on the given process. Since there is no reason to perform task_in_mem_cgroup() check for global OOM and oom_score procfs interface, those contexts provide NULL memcg and skips the task_in_mem_cgroup() check. However for memcg OOM context, the oom_unkillable_task() is always called from mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes redundant and effectively dead code. So, just remove the task_in_mem_cgroup() check altogether. Link: http://lkml.kernel.org/r/20190624212631.87212-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Jackson <pj@sgi.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Shakeel Butt
|
5eee7e1cdb |
mm, oom: refactor dump_tasks for memcg OOMs
dump_tasks() traverses all the existing processes even for the memcg OOM context which is not only unnecessary but also wasteful. This imposes a long RCU critical section even from a contained context which can be quite disruptive. Change dump_tasks() to be aligned with select_bad_process and use mem_cgroup_scan_tasks to selectively traverse only processes of the target memcg hierarchy during memcg OOM. Link: http://lkml.kernel.org/r/20190617231207.160865-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Paul Jackson <pj@sgi.com> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
|
f168a9a54e |
mm: memcontrol: use CSS_TASK_ITER_PROCS at mem_cgroup_scan_tasks()
Since commit
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Yafang Shao
|
432b1de0de |
mm/oom_kill.c: fix uninitialized oc->constraint
In dump_oom_summary() oc->constraint is used to show oom_constraint_text,
but it hasn't been set before. So the value of it is always the default
value 0. We should inititialize it before.
Bellow is the output when memcg oom occurs,
before this patch:
oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null), cpuset=/,mems_allowed=0,oom_memcg=/foo,task_memcg=/foo,task=bash,pid=7997,uid=0
after this patch:
oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null), cpuset=/,mems_allowed=0,oom_memcg=/foo,task_memcg=/foo,task=bash,pid=13681,uid=0
Link: http://lkml.kernel.org/r/1560522038-15879-1-git-send-email-laoar.shao@gmail.com
Fixes:
|
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Thomas Gleixner
|
457c899653 |
treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Jérôme Glisse
|
6f4f13e8d9 |
mm/mmu_notifier: contextual information for event triggering invalidation
CPU page table update can happens for many reasons, not only as a result
of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as
a result of kernel activities (memory compression, reclaim, migration,
...).
Users of mmu notifier API track changes to the CPU page table and take
specific action for them. While current API only provide range of virtual
address affected by the change, not why the changes is happening.
This patchset do the initial mechanical convertion of all the places that
calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP
event as well as the vma if it is know (most invalidation happens against
a given vma). Passing down the vma allows the users of mmu notifier to
inspect the new vma page protection.
The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier
should assume that every for the range is going away when that event
happens. A latter patch do convert mm call path to use a more appropriate
events for each call.
This is done as 2 patches so that no call site is forgotten especialy
as it uses this following coccinelle patch:
%<----------------------------------------------------------------------
@@
identifier I1, I2, I3, I4;
@@
static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1,
+enum mmu_notifier_event event,
+unsigned flags,
+struct vm_area_struct *vma,
struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... }
@@
@@
-#define mmu_notifier_range_init(range, mm, start, end)
+#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end)
@@
expression E1, E3, E4;
identifier I1;
@@
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, I1,
I1->vm_mm, E3, E4)
...>
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(..., struct vm_area_struct *VMA, ...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(...) {
struct vm_area_struct *VMA;
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, VMA,
E2, E3, E4)
...> }
@@
expression E1, E2, E3, E4;
identifier FN;
@@
FN(...) {
<...
mmu_notifier_range_init(E1,
+MMU_NOTIFY_UNMAP, 0, NULL,
E2, E3, E4)
...> }
---------------------------------------------------------------------->%
Applied with:
spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place
spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place
spatch --sp-file mmu-notifier.spatch --dir mm --in-place
Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Tetsuo Handa
|
d342a0b386 |
mm,oom: don't kill global init via memory.oom.group
Since setting global init process to some memory cgroup is technically
possible, oom_kill_memcg_member() must check it.
Tasks in /test1 are going to be killed due to memory.oom.group set
Memory cgroup out of memory: Killed process 1 (systemd) total-vm:43400kB, anon-rss:1228kB, file-rss:3992kB, shmem-rss:0kB
oom_reaper: reaped process 1 (systemd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000008b
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int main(int argc, char *argv[])
{
static char buffer[10485760];
static int pipe_fd[2] = { EOF, EOF };
unsigned int i;
int fd;
char buf[64] = { };
if (pipe(pipe_fd))
return 1;
if (chdir("/sys/fs/cgroup/"))
return 1;
fd = open("cgroup.subtree_control", O_WRONLY);
write(fd, "+memory", 7);
close(fd);
mkdir("test1", 0755);
fd = open("test1/memory.oom.group", O_WRONLY);
write(fd, "1", 1);
close(fd);
fd = open("test1/cgroup.procs", O_WRONLY);
write(fd, "1", 1);
snprintf(buf, sizeof(buf) - 1, "%d", getpid());
write(fd, buf, strlen(buf));
close(fd);
snprintf(buf, sizeof(buf) - 1, "%lu", sizeof(buffer) * 5);
fd = open("test1/memory.max", O_WRONLY);
write(fd, buf, strlen(buf));
close(fd);
for (i = 0; i < 10; i++)
if (fork() == 0) {
char c;
close(pipe_fd[1]);
read(pipe_fd[0], &c, 1);
memset(buffer, 0, sizeof(buffer));
sleep(3);
_exit(0);
}
close(pipe_fd[0]);
close(pipe_fd[1]);
sleep(3);
return 0;
}
[ 37.052923][ T9185] a.out invoked oom-killer: gfp_mask=0xcc0(GFP_KERNEL), order=0, oom_score_adj=0
[ 37.056169][ T9185] CPU: 4 PID: 9185 Comm: a.out Kdump: loaded Not tainted 5.0.0-rc4-next-20190131 #280
[ 37.059205][ T9185] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
[ 37.062954][ T9185] Call Trace:
[ 37.063976][ T9185] dump_stack+0x67/0x95
[ 37.065263][ T9185] dump_header+0x51/0x570
[ 37.066619][ T9185] ? trace_hardirqs_on+0x3f/0x110
[ 37.068171][ T9185] ? _raw_spin_unlock_irqrestore+0x3d/0x70
[ 37.069967][ T9185] oom_kill_process+0x18d/0x210
[ 37.071515][ T9185] out_of_memory+0x11b/0x380
[ 37.072936][ T9185] mem_cgroup_out_of_memory+0xb6/0xd0
[ 37.074601][ T9185] try_charge+0x790/0x820
[ 37.076021][ T9185] mem_cgroup_try_charge+0x42/0x1d0
[ 37.077629][ T9185] mem_cgroup_try_charge_delay+0x11/0x30
[ 37.079370][ T9185] do_anonymous_page+0x105/0x5e0
[ 37.080939][ T9185] __handle_mm_fault+0x9cb/0x1070
[ 37.082485][ T9185] handle_mm_fault+0x1b2/0x3a0
[ 37.083819][ T9185] ? handle_mm_fault+0x47/0x3a0
[ 37.085181][ T9185] __do_page_fault+0x255/0x4c0
[ 37.086529][ T9185] do_page_fault+0x28/0x260
[ 37.087788][ T9185] ? page_fault+0x8/0x30
[ 37.088978][ T9185] page_fault+0x1e/0x30
[ 37.090142][ T9185] RIP: 0033:0x7f8b183aefe0
[ 37.091433][ T9185] Code: 20 f3 44 0f 7f 44 17 d0 f3 44 0f 7f 47 30 f3 44 0f 7f 44 17 c0 48 01 fa 48 83 e2 c0 48 39 d1 74 a3 66 0f 1f 84 00 00 00 00 00 <66> 44 0f 7f 01 66 44 0f 7f 41 10 66 44 0f 7f 41 20 66 44 0f 7f 41
[ 37.096917][ T9185] RSP: 002b:00007fffc5d329e8 EFLAGS: 00010206
[ 37.098615][ T9185] RAX: 00000000006010e0 RBX: 0000000000000008 RCX: 0000000000c30000
[ 37.100905][ T9185] RDX: 00000000010010c0 RSI: 0000000000000000 RDI: 00000000006010e0
[ 37.103349][ T9185] RBP: 0000000000000000 R08: 00007f8b188f4740 R09: 0000000000000000
[ 37.105797][ T9185] R10: 00007fffc5d32420 R11: 00007f8b183aef40 R12: 0000000000000005
[ 37.108228][ T9185] R13: 0000000000000000 R14: ffffffffffffffff R15: 0000000000000000
[ 37.110840][ T9185] memory: usage 51200kB, limit 51200kB, failcnt 125
[ 37.113045][ T9185] memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0
[ 37.115808][ T9185] kmem: usage 0kB, limit 9007199254740988kB, failcnt 0
[ 37.117660][ T9185] Memory cgroup stats for /test1: cache:0KB rss:49484KB rss_huge:30720KB shmem:0KB mapped_file:0KB dirty:0KB writeback:0KB inactive_anon:0KB active_anon:49700KB inactive_file:0KB active_file:0KB unevictable:0KB
[ 37.123371][ T9185] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/test1,task_memcg=/test1,task=a.out,pid=9188,uid=0
[ 37.128158][ T9185] Memory cgroup out of memory: Killed process 9188 (a.out) total-vm:14456kB, anon-rss:10324kB, file-rss:504kB, shmem-rss:0kB
[ 37.132710][ T9185] Tasks in /test1 are going to be killed due to memory.oom.group set
[ 37.132833][ T54] oom_reaper: reaped process 9188 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.135498][ T9185] Memory cgroup out of memory: Killed process 1 (systemd) total-vm:43400kB, anon-rss:1228kB, file-rss:3992kB, shmem-rss:0kB
[ 37.143434][ T9185] Memory cgroup out of memory: Killed process 9182 (a.out) total-vm:14456kB, anon-rss:76kB, file-rss:588kB, shmem-rss:0kB
[ 37.144328][ T54] oom_reaper: reaped process 1 (systemd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.147585][ T9185] Memory cgroup out of memory: Killed process 9183 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB
[ 37.157222][ T9185] Memory cgroup out of memory: Killed process 9184 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:508kB, shmem-rss:0kB
[ 37.157259][ T9185] Memory cgroup out of memory: Killed process 9185 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB
[ 37.157291][ T9185] Memory cgroup out of memory: Killed process 9186 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:508kB, shmem-rss:0kB
[ 37.157306][ T54] oom_reaper: reaped process 9183 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.157328][ T9185] Memory cgroup out of memory: Killed process 9187 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:512kB, shmem-rss:0kB
[ 37.157452][ T9185] Memory cgroup out of memory: Killed process 9189 (a.out) total-vm:14456kB, anon-rss:6228kB, file-rss:512kB, shmem-rss:0kB
[ 37.158733][ T9185] Memory cgroup out of memory: Killed process 9190 (a.out) total-vm:14456kB, anon-rss:552kB, file-rss:512kB, shmem-rss:0kB
[ 37.160083][ T54] oom_reaper: reaped process 9186 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.160187][ T54] oom_reaper: reaped process 9189 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.206941][ T54] oom_reaper: reaped process 9185 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.212300][ T9185] Memory cgroup out of memory: Killed process 9191 (a.out) total-vm:14456kB, anon-rss:4180kB, file-rss:512kB, shmem-rss:0kB
[ 37.212317][ T54] oom_reaper: reaped process 9190 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.218860][ T9185] Memory cgroup out of memory: Killed process 9192 (a.out) total-vm:14456kB, anon-rss:1080kB, file-rss:512kB, shmem-rss:0kB
[ 37.227667][ T54] oom_reaper: reaped process 9192 (a.out), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
[ 37.292323][ T9193] abrt-hook-ccpp (9193) used greatest stack depth: 10480 bytes left
[ 37.351843][ T1] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000008b
[ 37.354833][ T1] CPU: 7 PID: 1 Comm: systemd Kdump: loaded Not tainted 5.0.0-rc4-next-20190131 #280
[ 37.357876][ T1] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
[ 37.361685][ T1] Call Trace:
[ 37.363239][ T1] dump_stack+0x67/0x95
[ 37.365010][ T1] panic+0xfc/0x2b0
[ 37.366853][ T1] do_exit+0xd55/0xd60
[ 37.368595][ T1] do_group_exit+0x47/0xc0
[ 37.370415][ T1] get_signal+0x32a/0x920
[ 37.372449][ T1] ? _raw_spin_unlock_irqrestore+0x3d/0x70
[ 37.374596][ T1] do_signal+0x32/0x6e0
[ 37.376430][ T1] ? exit_to_usermode_loop+0x26/0x9b
[ 37.378418][ T1] ? prepare_exit_to_usermode+0xa8/0xd0
[ 37.380571][ T1] exit_to_usermode_loop+0x3e/0x9b
[ 37.382588][ T1] prepare_exit_to_usermode+0xa8/0xd0
[ 37.384594][ T1] ? page_fault+0x8/0x30
[ 37.386453][ T1] retint_user+0x8/0x18
[ 37.388160][ T1] RIP: 0033:0x7f42c06974a8
[ 37.389922][ T1] Code: Bad RIP value.
[ 37.391788][ T1] RSP: 002b:00007ffc3effd388 EFLAGS: 00010213
[ 37.394075][ T1] RAX: 000000000000000e RBX: 00007ffc3effd390 RCX: 0000000000000000
[ 37.396963][ T1] RDX: 000000000000002a RSI: 00007ffc3effd390 RDI: 0000000000000004
[ 37.399550][ T1] RBP: 00007ffc3effd680 R08: 0000000000000000 R09: 0000000000000000
[ 37.402334][ T1] R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001
[ 37.404890][ T1] R13: ffffffffffffffff R14: 0000000000000884 R15: 000056460b1ac3b0
Link: http://lkml.kernel.org/r/201902010336.x113a4EO027170@www262.sakura.ne.jp
Fixes:
|
||
|
Shakeel Butt
|
bbbe480297 |
mm, oom: remove 'prefer children over parent' heuristic
Since the start of the git history of Linux, the kernel after selecting the worst process to be oom-killed, prefer to kill its child (if the child does not share mm with the parent). Later it was changed to prefer to kill a child who is worst. If the parent is still the worst then the parent will be killed. This heuristic assumes that the children did less work than their parent and by killing one of them, the work lost will be less. However this is very workload dependent. If there is a workload which can benefit from this heuristic, can use oom_score_adj to prefer children to be killed before the parent. The select_bad_process() has already selected the worst process in the system/memcg. There is no need to recheck the badness of its children and hoping to find a worse candidate. That's a lot of unneeded racy work. Also the heuristic is dangerous because it make fork bomb like workloads to recover much later because we constantly pick and kill processes which are not memory hogs. So, let's remove this whole heuristic. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190121215850.221745-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shakeel Butt
|
cefc7ef3c8 |
mm, oom: fix use-after-free in oom_kill_process
Syzbot instance running on upstream kernel found a use-after-free bug in
oom_kill_process. On further inspection it seems like the process
selected to be oom-killed has exited even before reaching
read_lock(&tasklist_lock) in oom_kill_process(). More specifically the
tsk->usage is 1 which is due to get_task_struct() in oom_evaluate_task()
and the put_task_struct within for_each_thread() frees the tsk and
for_each_thread() tries to access the tsk. The easiest fix is to do
get/put across the for_each_thread() on the selected task.
Now the next question is should we continue with the oom-kill as the
previously selected task has exited? However before adding more
complexity and heuristics, let's answer why we even look at the children
of oom-kill selected task? The select_bad_process() has already selected
the worst process in the system/memcg. Due to race, the selected
process might not be the worst at the kill time but does that matter?
The userspace can use the oom_score_adj interface to prefer children to
be killed before the parent. I looked at the history but it seems like
this is there before git history.
Link: http://lkml.kernel.org/r/20190121215850.221745-1-shakeelb@google.com
Reported-by: syzbot+7fbbfa368521945f0e3d@syzkaller.appspotmail.com
Fixes:
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Tetsuo Handa
|
9bcdeb51bd |
oom, oom_reaper: do not enqueue same task twice
Arkadiusz reported that enabling memcg's group oom killing causes
strange memcg statistics where there is no task in a memcg despite the
number of tasks in that memcg is not 0. It turned out that there is a
bug in wake_oom_reaper() which allows enqueuing same task twice which
makes impossible to decrease the number of tasks in that memcg due to a
refcount leak.
This bug existed since the OOM reaper became invokable from
task_will_free_mem(current) path in out_of_memory() in Linux 4.7,
T1@P1 |T2@P1 |T3@P1 |OOM reaper
----------+----------+----------+------------
# Processing an OOM victim in a different memcg domain.
try_charge()
mem_cgroup_out_of_memory()
mutex_lock(&oom_lock)
try_charge()
mem_cgroup_out_of_memory()
mutex_lock(&oom_lock)
try_charge()
mem_cgroup_out_of_memory()
mutex_lock(&oom_lock)
out_of_memory()
oom_kill_process(P1)
do_send_sig_info(SIGKILL, @P1)
mark_oom_victim(T1@P1)
wake_oom_reaper(T1@P1) # T1@P1 is enqueued.
mutex_unlock(&oom_lock)
out_of_memory()
mark_oom_victim(T2@P1)
wake_oom_reaper(T2@P1) # T2@P1 is enqueued.
mutex_unlock(&oom_lock)
out_of_memory()
mark_oom_victim(T1@P1)
wake_oom_reaper(T1@P1) # T1@P1 is enqueued again due to oom_reaper_list == T2@P1 && T1@P1->oom_reaper_list == NULL.
mutex_unlock(&oom_lock)
# Completed processing an OOM victim in a different memcg domain.
spin_lock(&oom_reaper_lock)
# T1P1 is dequeued.
spin_unlock(&oom_reaper_lock)
but memcg's group oom killing made it easier to trigger this bug by
calling wake_oom_reaper() on the same task from one out_of_memory()
request.
Fix this bug using an approach used by commit
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Jérôme Glisse
|
ac46d4f3c4 |
mm/mmu_notifier: use structure for invalidate_range_start/end calls v2
To avoid having to change many call sites everytime we want to add a parameter use a structure to group all parameters for the mmu_notifier invalidate_range_start/end cakks. No functional changes with this patch. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Felix Kuehling <felix.kuehling@amd.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> From: Jérôme Glisse <jglisse@redhat.com> Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3 fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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yuzhoujian
|
f0c867d958 |
mm, oom: add oom victim's memcg to the oom context information
The current oom report doesn't display victim's memcg context during the global OOM situation. While this information is not strictly needed, it can be really helpful for containerized environments to locate which container has lost a process. Now that we have a single line for the oom context, we can trivially add both the oom memcg (this can be either global_oom or a specific memcg which hits its hard limits) and task_memcg which is the victim's memcg. Below is the single line output in the oom report after this patch. - global oom context information: oom-kill:constraint=<constraint>,nodemask=<nodemask>,cpuset=<cpuset>,mems_allowed=<mems_allowed>,global_oom,task_memcg=<memcg>,task=<comm>,pid=<pid>,uid=<uid> - memcg oom context information: oom-kill:constraint=<constraint>,nodemask=<nodemask>,cpuset=<cpuset>,mems_allowed=<mems_allowed>,oom_memcg=<memcg>,task_memcg=<memcg>,task=<comm>,pid=<pid>,uid=<uid> [penguin-kernel@I-love.SAKURA.ne.jp: use pr_cont() in mem_cgroup_print_oom_context()] Link: http://lkml.kernel.org/r/201812190723.wBJ7NdkN032628@www262.sakura.ne.jp Link: http://lkml.kernel.org/r/1542799799-36184-2-git-send-email-ufo19890607@gmail.com Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Roman Gushchin <guro@fb.com> Cc: Yang Shi <yang.s@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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yuzhoujian
|
ef8444ea01 |
mm, oom: reorganize the oom report in dump_header
OOM report contains several sections. The first one is the allocation context that has triggered the OOM. Then we have cpuset context followed by the stack trace of the OOM path. The tird one is the OOM memory information. Followed by the current memory state of all system tasks. At last, we will show oom eligible tasks and the information about the chosen oom victim. One thing that makes parsing more awkward than necessary is that we do not have a single and easily parsable line about the oom context. This patch is reorganizing the oom report to 1) who invoked oom and what was the allocation request [ 515.902945] tuned invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0 2) OOM stack trace [ 515.904273] CPU: 24 PID: 1809 Comm: tuned Not tainted 4.20.0-rc3+ #3 [ 515.905518] Hardware name: Inspur SA5212M4/YZMB-00370-107, BIOS 4.1.10 11/14/2016 [ 515.906821] Call Trace: [ 515.908062] dump_stack+0x5a/0x73 [ 515.909311] dump_header+0x55/0x28c [ 515.914260] oom_kill_process+0x2d8/0x300 [ 515.916708] out_of_memory+0x145/0x4a0 [ 515.917932] __alloc_pages_slowpath+0x7d2/0xa16 [ 515.919157] __alloc_pages_nodemask+0x277/0x290 [ 515.920367] filemap_fault+0x3d0/0x6c0 [ 515.921529] ? filemap_map_pages+0x2b8/0x420 [ 515.922709] ext4_filemap_fault+0x2c/0x40 [ext4] [ 515.923884] __do_fault+0x20/0x80 [ 515.925032] __handle_mm_fault+0xbc0/0xe80 [ 515.926195] handle_mm_fault+0xfa/0x210 [ 515.927357] __do_page_fault+0x233/0x4c0 [ 515.928506] do_page_fault+0x32/0x140 [ 515.929646] ? page_fault+0x8/0x30 [ 515.930770] page_fault+0x1e/0x30 3) OOM memory information [ 515.958093] Mem-Info: [ 515.959647] active_anon:26501758 inactive_anon:1179809 isolated_anon:0 active_file:4402672 inactive_file:483963 isolated_file:1344 unevictable:0 dirty:4886753 writeback:0 unstable:0 slab_reclaimable:148442 slab_unreclaimable:18741 mapped:1347 shmem:1347 pagetables:58669 bounce:0 free:88663 free_pcp:0 free_cma:0 ... 4) current memory state of all system tasks [ 516.079544] [ 744] 0 744 9211 1345 114688 82 0 systemd-journal [ 516.082034] [ 787] 0 787 31764 0 143360 92 0 lvmetad [ 516.084465] [ 792] 0 792 10930 1 110592 208 -1000 systemd-udevd [ 516.086865] [ 1199] 0 1199 13866 0 131072 112 -1000 auditd [ 516.089190] [ 1222] 0 1222 31990 1 110592 157 0 smartd [ 516.091477] [ 1225] 0 1225 4864 85 81920 43 0 irqbalance [ 516.093712] [ 1226] 0 1226 52612 0 258048 426 0 abrtd [ 516.112128] [ 1280] 0 1280 109774 55 299008 400 0 NetworkManager [ 516.113998] [ 1295] 0 1295 28817 37 69632 24 0 ksmtuned [ 516.144596] [ 10718] 0 10718 2622484 1721372 15998976 267219 0 panic [ 516.145792] [ 10719] 0 10719 2622484 1164767 9818112 53576 0 panic [ 516.146977] [ 10720] 0 10720 2622484 1174361 9904128 53709 0 panic [ 516.148163] [ 10721] 0 10721 2622484 1209070 10194944 54824 0 panic [ 516.149329] [ 10722] 0 10722 2622484 1745799 14774272 91138 0 panic 5) oom context (contrains and the chosen victim). oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0-1,task=panic,pid=10737,uid=0 An admin can easily get the full oom context at a single line which makes parsing much easier. Link: http://lkml.kernel.org/r/1542799799-36184-1-git-send-email-ufo19890607@gmail.com Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Yang Shi <yang.s@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Arun KS
|
ca79b0c211 |
mm: convert totalram_pages and totalhigh_pages variables to atomic
totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
|
ba9f6f8954 |
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull siginfo updates from Eric Biederman: "I have been slowly sorting out siginfo and this is the culmination of that work. The primary result is in several ways the signal infrastructure has been made less error prone. The code has been updated so that manually specifying SEND_SIG_FORCED is never necessary. The conversion to the new siginfo sending functions is now complete, which makes it difficult to send a signal without filling in the proper siginfo fields. At the tail end of the patchset comes the optimization of decreasing the size of struct siginfo in the kernel from 128 bytes to about 48 bytes on 64bit. The fundamental observation that enables this is by definition none of the known ways to use struct siginfo uses the extra bytes. This comes at the cost of a small user space observable difference. For the rare case of siginfo being injected into the kernel only what can be copied into kernel_siginfo is delivered to the destination, the rest of the bytes are set to 0. For cases where the signal and the si_code are known this is safe, because we know those bytes are not used. For cases where the signal and si_code combination is unknown the bits that won't fit into struct kernel_siginfo are tested to verify they are zero, and the send fails if they are not. I made an extensive search through userspace code and I could not find anything that would break because of the above change. If it turns out I did break something it will take just the revert of a single change to restore kernel_siginfo to the same size as userspace siginfo. Testing did reveal dependencies on preferring the signo passed to sigqueueinfo over si->signo, so bit the bullet and added the complexity necessary to handle that case. Testing also revealed bad things can happen if a negative signal number is passed into the system calls. Something no sane application will do but something a malicious program or a fuzzer might do. So I have fixed the code that performs the bounds checks to ensure negative signal numbers are handled" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits) signal: Guard against negative signal numbers in copy_siginfo_from_user32 signal: Guard against negative signal numbers in copy_siginfo_from_user signal: In sigqueueinfo prefer sig not si_signo signal: Use a smaller struct siginfo in the kernel signal: Distinguish between kernel_siginfo and siginfo signal: Introduce copy_siginfo_from_user and use it's return value signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Fail sigqueueinfo if si_signo != sig signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal/unicore32: Use force_sig_fault where appropriate signal/unicore32: Generate siginfo in ucs32_notify_die signal/unicore32: Use send_sig_fault where appropriate signal/arc: Use force_sig_fault where appropriate signal/arc: Push siginfo generation into unhandled_exception signal/ia64: Use force_sig_fault where appropriate signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn signal/ia64: Use the generic force_sigsegv in setup_frame signal/arm/kvm: Use send_sig_mceerr signal/arm: Use send_sig_fault where appropriate signal/arm: Use force_sig_fault where appropriate ... |
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Eric W. Biederman
|
079b22dc9b |
signal: Use SEND_SIG_PRIV not SEND_SIG_FORCED with SIGKILL and SIGSTOP
Now that siginfo is never allocated for SIGKILL and SIGSTOP there is no difference between SEND_SIG_PRIV and SEND_SIG_FORCED for SIGKILL and SIGSTOP. This makes SEND_SIG_FORCED unnecessary and redundant in the presence of SIGKILL and SIGSTOP. Therefore change users of SEND_SIG_FORCED that are sending SIGKILL or SIGSTOP to use SEND_SIG_PRIV instead. This removes the last users of SEND_SIG_FORCED. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Tetsuo Handa
|
79cc81057e |
mm, oom: fix missing tlb_finish_mmu() in __oom_reap_task_mm().
Commit
|
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Johannes Weiner
|
3100dab2aa |
mm: memcontrol: print proper OOM header when no eligible victim left
When the memcg OOM killer runs out of killable tasks, it currently prints a WARN with no further OOM context. This has caused some user confusion. Warnings indicate a kernel problem. In a reported case, however, the situation was triggered by a nonsensical memcg configuration (hard limit set to 0). But without any VM context this wasn't obvious from the report, and it took some back and forth on the mailing list to identify what is actually a trivial issue. Handle this OOM condition like we handle it in the global OOM killer: dump the full OOM context and tell the user we ran out of tasks. This way the user can identify misconfigurations easily by themselves and rectify the problem - without having to go through the hassle of running into an obscure but unsettling warning, finding the appropriate kernel mailing list and waiting for a kernel developer to remote-analyze that the memcg configuration caused this. If users cannot make sense of why the OOM killer was triggered or why it failed, they will still report it to the mailing list, we know that from experience. So in case there is an actual kernel bug causing this, kernel developers will very likely hear about it. Link: http://lkml.kernel.org/r/20180821160406.22578-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
|
cd9b44f907 |
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: - the rest of MM - procfs updates - various misc things - more y2038 fixes - get_maintainer updates - lib/ updates - checkpatch updates - various epoll updates - autofs updates - hfsplus - some reiserfs work - fatfs updates - signal.c cleanups - ipc/ updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (166 commits) ipc/util.c: update return value of ipc_getref from int to bool ipc/util.c: further variable name cleanups ipc: simplify ipc initialization ipc: get rid of ids->tables_initialized hack lib/rhashtable: guarantee initial hashtable allocation lib/rhashtable: simplify bucket_table_alloc() ipc: drop ipc_lock() ipc/util.c: correct comment in ipc_obtain_object_check ipc: rename ipcctl_pre_down_nolock() ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() ipc: reorganize initialization of kern_ipc_perm.seq ipc: compute kern_ipc_perm.id under the ipc lock init/Kconfig: remove EXPERT from CHECKPOINT_RESTORE fs/sysv/inode.c: use ktime_get_real_seconds() for superblock stamp adfs: use timespec64 for time conversion kernel/sysctl.c: fix typos in comments drivers/rapidio/devices/rio_mport_cdev.c: remove redundant pointer md fork: don't copy inconsistent signal handler state to child signal: make get_signal() return bool signal: make sigkill_pending() return bool ... |
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Roman Gushchin
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3d8b38eb81 |
mm, oom: introduce memory.oom.group
For some workloads an intervention from the OOM killer can be painful. Killing a random task can bring the workload into an inconsistent state. Historically, there are two common solutions for this problem: 1) enabling panic_on_oom, 2) using a userspace daemon to monitor OOMs and kill all outstanding processes. Both approaches have their downsides: rebooting on each OOM is an obvious waste of capacity, and handling all in userspace is tricky and requires a userspace agent, which will monitor all cgroups for OOMs. In most cases an in-kernel after-OOM cleaning-up mechanism can eliminate the necessity of enabling panic_on_oom. Also, it can simplify the cgroup management for userspace applications. This commit introduces a new knob for cgroup v2 memory controller: memory.oom.group. The knob determines whether the cgroup should be treated as an indivisible workload by the OOM killer. If set, all tasks belonging to the cgroup or to its descendants (if the memory cgroup is not a leaf cgroup) are killed together or not at all. To determine which cgroup has to be killed, we do traverse the cgroup hierarchy from the victim task's cgroup up to the OOMing cgroup (or root) and looking for the highest-level cgroup with memory.oom.group set. Tasks with the OOM protection (oom_score_adj set to -1000) are treated as an exception and are never killed. This patch doesn't change the OOM victim selection algorithm. Link: http://lkml.kernel.org/r/20180802003201.817-4-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Roman Gushchin
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5989ad7b5e |
mm, oom: refactor oom_kill_process()
Patch series "introduce memory.oom.group", v2. This is a tiny implementation of cgroup-aware OOM killer, which adds an ability to kill a cgroup as a single unit and so guarantee the integrity of the workload. Although it has only a limited functionality in comparison to what now resides in the mm tree (it doesn't change the victim task selection algorithm, doesn't look at memory stas on cgroup level, etc), it's also much simpler and more straightforward. So, hopefully, we can avoid having long debates here, as we had with the full implementation. As it doesn't prevent any futher development, and implements an useful and complete feature, it looks as a sane way forward. This patch (of 2): oom_kill_process() consists of two logical parts: the first one is responsible for considering task's children as a potential victim and printing the debug information. The second half is responsible for sending SIGKILL to all tasks sharing the mm struct with the given victim. This commit splits oom_kill_process() with an intention to re-use the the second half: __oom_kill_process(). The cgroup-aware OOM killer will kill multiple tasks belonging to the victim cgroup. We don't need to print the debug information for the each task, as well as play with task selection (considering task's children), so we can't use the existing oom_kill_process(). Link: http://lkml.kernel.org/r/20171130152824.1591-2-guro@fb.com Link: http://lkml.kernel.org/r/20180802003201.817-3-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
|
431f42fdfd |
mm/oom_kill.c: clean up oom_reap_task_mm()
Andrew has noticed some inconsistencies in oom_reap_task_mm. Notably - Undocumented return value. - comment "failed to reap part..." is misleading - sounds like it's referring to something which happened in the past, is in fact referring to something which might happen in the future. - fails to call trace_finish_task_reaping() in one case - code duplication. - Increases mmap_sem hold time a little by moving trace_finish_task_reaping() inside the locked region. So sue me ;) - Sharing the finish: path means that the trace event won't distinguish between the two sources of finishing. Add a short explanation for the return value and fix the rest by reorganizing the function a bit to have unified function exit paths. Link: http://lkml.kernel.org/r/20180724141747.GP28386@dhcp22.suse.cz Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rodrigo Freire
|
c3b78b11ef |
mm, oom: describe task memory unit, larger PID pad
The default page memory unit of OOM task dump events might not be intuitive and potentially misleading for the non-initiated when debugging OOM events: These are pages and not kBs. Add a small printk prior to the task dump informing that the memory units are actually memory _pages_. Also extends PID field to align on up to 7 characters. Reference https://lkml.org/lkml/2018/7/3/1201 Link: http://lkml.kernel.org/r/c795eb5129149ed8a6345c273aba167ff1bbd388.1530715938.git.rfreire@redhat.com Signed-off-by: Rodrigo Freire <rfreire@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Michal Hocko
|
af5679fbc6 |
mm, oom: remove oom_lock from oom_reaper
oom_reaper used to rely on the oom_lock since |
||
|
Michal Hocko
|
93065ac753 |
mm, oom: distinguish blockable mode for mmu notifiers
There are several blockable mmu notifiers which might sleep in mmu_notifier_invalidate_range_start and that is a problem for the oom_reaper because it needs to guarantee a forward progress so it cannot depend on any sleepable locks. Currently we simply back off and mark an oom victim with blockable mmu notifiers as done after a short sleep. That can result in selecting a new oom victim prematurely because the previous one still hasn't torn its memory down yet. We can do much better though. Even if mmu notifiers use sleepable locks there is no reason to automatically assume those locks are held. Moreover majority of notifiers only care about a portion of the address space and there is absolutely zero reason to fail when we are unmapping an unrelated range. Many notifiers do really block and wait for HW which is harder to handle and we have to bail out though. This patch handles the low hanging fruit. __mmu_notifier_invalidate_range_start gets a blockable flag and callbacks are not allowed to sleep if the flag is set to false. This is achieved by using trylock instead of the sleepable lock for most callbacks and continue as long as we do not block down the call chain. I think we can improve that even further because there is a common pattern to do a range lookup first and then do something about that. The first part can be done without a sleeping lock in most cases AFAICS. The oom_reaper end then simply retries if there is at least one notifier which couldn't make any progress in !blockable mode. A retry loop is already implemented to wait for the mmap_sem and this is basically the same thing. The simplest way for driver developers to test this code path is to wrap userspace code which uses these notifiers into a memcg and set the hard limit to hit the oom. This can be done e.g. after the test faults in all the mmu notifier managed memory and set the hard limit to something really small. Then we are looking for a proper process tear down. [akpm@linux-foundation.org: coding style fixes] [akpm@linux-foundation.org: minor code simplification] Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp Reported-by: David Rientjes <rientjes@google.com> Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Dennis Dalessandro <dennis.dalessandro@intel.com> Cc: Sudeep Dutt <sudeep.dutt@intel.com> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
|
0214f46b3a |
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman:
"It was observed that a periodic timer in combination with a
sufficiently expensive fork could prevent fork from every completing.
This contains the changes to remove the need for that restart.
This set of changes is split into several parts:
- The first part makes PIDTYPE_TGID a proper pid type instead
something only for very special cases. The part starts using
PIDTYPE_TGID enough so that in __send_signal where signals are
actually delivered we know if the signal is being sent to a a group
of processes or just a single process.
- With that prep work out of the way the logic in fork is modified so
that fork logically makes signals received while it is running
appear to be received after the fork completes"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
signal: Don't send signals to tasks that don't exist
signal: Don't restart fork when signals come in.
fork: Have new threads join on-going signal group stops
fork: Skip setting TIF_SIGPENDING in ptrace_init_task
signal: Add calculate_sigpending()
fork: Unconditionally exit if a fatal signal is pending
fork: Move and describe why the code examines PIDNS_ADDING
signal: Push pid type down into complete_signal.
signal: Push pid type down into __send_signal
signal: Push pid type down into send_signal
signal: Pass pid type into do_send_sig_info
signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
signal: Pass pid type into group_send_sig_info
signal: Pass pid and pid type into send_sigqueue
posix-timers: Noralize good_sigevent
signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
pid: Implement PIDTYPE_TGID
pids: Move the pgrp and session pid pointers from task_struct to signal_struct
kvm: Don't open code task_pid in kvm_vcpu_ioctl
pids: Compute task_tgid using signal->leader_pid
...
|
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Michal Hocko
|
a195d3f5b7 |
mm/oom_kill.c: document oom_lock
Add comments describing oom_lock's scope. Requested-by: David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/20180711120121.25635-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
|
9bfe5ded05 |
mm, oom: remove sleep from under oom_lock
Tetsuo has pointed out that since
|
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Eric W. Biederman
|
40b3b02535 |
signal: Pass pid type into do_send_sig_info
This passes the information we already have at the call sight into do_send_sig_info. Ultimately allowing for better handling of signals sent to a group of processes during fork. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Roman Gushchin
|
fe6bdfc8e1 |
mm: fix oom_kill event handling
Commit
|
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Roman Gushchin
|
bbec2e1517 |
mm: rename page_counter's count/limit into usage/max
This patch renames struct page_counter fields: count -> usage limit -> max and the corresponding functions: page_counter_limit() -> page_counter_set_max() mem_cgroup_get_limit() -> mem_cgroup_get_max() mem_cgroup_resize_limit() -> mem_cgroup_resize_max() memcg_update_kmem_limit() -> memcg_update_kmem_max() memcg_update_tcp_limit() -> memcg_update_tcp_max() The idea behind this renaming is to have the direct matching between memory cgroup knobs (low, high, max) and page_counters API. This is pure renaming, this patch doesn't bring any functional change. Link: http://lkml.kernel.org/r/20180405185921.4942-1-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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David Rientjes
|
27ae357fa8 |
mm, oom: fix concurrent munlock and oom reaper unmap, v3
Since exit_mmap() is done without the protection of mm->mmap_sem, it is
possible for the oom reaper to concurrently operate on an mm until
MMF_OOM_SKIP is set.
This allows munlock_vma_pages_all() to concurrently run while the oom
reaper is operating on a vma. Since munlock_vma_pages_range() depends
on clearing VM_LOCKED from vm_flags before actually doing the munlock to
determine if any other vmas are locking the same memory, the check for
VM_LOCKED in the oom reaper is racy.
This is especially noticeable on architectures such as powerpc where
clearing a huge pmd requires serialize_against_pte_lookup(). If the pmd
is zapped by the oom reaper during follow_page_mask() after the check
for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a
kernel oops.
Fix this by manually freeing all possible memory from the mm before
doing the munlock and then setting MMF_OOM_SKIP. The oom reaper can not
run on the mm anymore so the munlock is safe to do in exit_mmap(). It
also matches the logic that the oom reaper currently uses for
determining when to set MMF_OOM_SKIP itself, so there's no new risk of
excessive oom killing.
This issue fixes CVE-2018-1000200.
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com
Fixes:
|
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|
Tetsuo Handa
|
97b1255cb2 |
mm,oom_reaper: check for MMF_OOM_SKIP before complaining
I got "oom_reaper: unable to reap pid:" messages when the victim thread was blocked inside free_pgtables() (which occurred after returning from unmap_vmas() and setting MMF_OOM_SKIP). We don't need to complain when exit_mmap() already set MMF_OOM_SKIP. Killed process 7558 (a.out) total-vm:4176kB, anon-rss:84kB, file-rss:0kB, shmem-rss:0kB oom_reaper: unable to reap pid:7558 (a.out) a.out D13272 7558 6931 0x00100084 Call Trace: schedule+0x2d/0x80 rwsem_down_write_failed+0x2bb/0x440 call_rwsem_down_write_failed+0x13/0x20 down_write+0x49/0x60 unlink_file_vma+0x28/0x50 free_pgtables+0x36/0x100 exit_mmap+0xbb/0x180 mmput+0x50/0x110 copy_process.part.41+0xb61/0x1fe0 _do_fork+0xe6/0x560 do_syscall_64+0x74/0x230 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Link: http://lkml.kernel.org/r/201803221946.DHG65638.VFJHFtOSQLOMOF@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
David Rientjes
|
d46078b288 |
mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
Since the 2.6 kernel, the oom killer has slightly biased away from CAP_SYS_ADMIN processes by discounting some of its memory usage in comparison to other processes. This has always been implicit and nothing exactly relies on the behavior. Gaurav notices that __task_cred() can dereference a potentially freed pointer if the task under consideration is exiting because a reference to the task_struct is not held. Remove the CAP_SYS_ADMIN bias so that all processes are treated equally. If any CAP_SYS_ADMIN process would like to be biased against, it is always allowed to adjust /proc/pid/oom_score_adj. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803071548510.6996@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Gaurav Kohli <gkohli@codeaurora.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Mike Rapoport
|
e8b098fc57 |
mm: kernel-doc: add missing parameter descriptions
Link: http://lkml.kernel.org/r/1519585191-10180-4-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
David Rientjes
|
f340ff8203 |
mm, oom: avoid reaping only for mm's with blockable invalidate callbacks
This uses the new annotation to determine if an mm has mmu notifiers with blockable invalidate range callbacks to avoid oom reaping. Otherwise, the callbacks are used around unmap_page_range(). Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1712141330120.74052@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dimitri Sivanich <sivanich@hpe.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Joerg Roedel <joro@8bytes.org> Cc: Doug Ledford <dledford@redhat.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Michal Hocko
|
4837fe37ad |
mm, oom_reaper: fix memory corruption
David Rientjes has reported the following memory corruption while the
oom reaper tries to unmap the victims address space
BUG: Bad page map in process oom_reaper pte:6353826300000000 pmd:00000000
addr:00007f50cab1d000 vm_flags:08100073 anon_vma:ffff9eea335603f0 mapping: (null) index:7f50cab1d
file: (null) fault: (null) mmap: (null) readpage: (null)
CPU: 2 PID: 1001 Comm: oom_reaper
Call Trace:
unmap_page_range+0x1068/0x1130
__oom_reap_task_mm+0xd5/0x16b
oom_reaper+0xff/0x14c
kthread+0xc1/0xe0
Tetsuo Handa has noticed that the synchronization inside exit_mmap is
insufficient. We only synchronize with the oom reaper if
tsk_is_oom_victim which is not true if the final __mmput is called from
a different context than the oom victim exit path. This can trivially
happen from context of any task which has grabbed mm reference (e.g. to
read /proc/<pid>/ file which requires mm etc.).
The race would look like this
oom_reaper oom_victim task
mmget_not_zero
do_exit
mmput
__oom_reap_task_mm mmput
__mmput
exit_mmap
remove_vma
unmap_page_range
Fix this issue by providing a new mm_is_oom_victim() helper which
operates on the mm struct rather than a task. Any context which
operates on a remote mm struct should use this helper in place of
tsk_is_oom_victim. The flag is set in mark_oom_victim and never cleared
so it is stable in the exit_mmap path.
Debugged by Tetsuo Handa.
Link: http://lkml.kernel.org/r/20171210095130.17110-1-mhocko@kernel.org
Fixes:
|
||
Wang Nan
|
687cb0884a |
mm, oom_reaper: gather each vma to prevent leaking TLB entry
tlb_gather_mmu(&tlb, mm, 0, -1) means gathering the whole virtual memory space. In this case, tlb->fullmm is true. Some archs like arm64 doesn't flush TLB when tlb->fullmm is true: commit |
||
|
Michal Hocko
|
0205f75571 |
mm: simplify nodemask printing
alloc_warn() and dump_header() have to explicitly handle NULL nodemask which forces both paths to use pr_cont. We can do better. printk already handles NULL pointers properly so all we need is to teach nodemask_pr_args to handle NULL nodemask carefully. This allows simplification of both alloc_warn() and dump_header() and gets rid of pr_cont altogether. This patch has been motivated by patch from Joe Perches http://lkml.kernel.org/r/b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@perches.com [akpm@linux-foundation.org: fix tile warning, per Arnd] Link: http://lkml.kernel.org/r/20171109100531.3cn2hcqnuj7mjaju@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Joe Perches <joe@perches.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Tetsuo Handa
|
c50842c8e1 |
mm,oom_reaper: remove pointless kthread_run() error check
Since oom_init() is called before userspace processes start, memory allocation failure for creating the OOM reaper kernel thread will let the OOM killer call panic() rather than wake up the OOM reaper. Link: http://lkml.kernel.org/r/1510137800-4602-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
Kirill A. Shutemov
|
af5b0f6a09 |
mm: consolidate page table accounting
Currently, we account page tables separately for each page table level, but that's redundant -- we only make use of total memory allocated to page tables for oom_badness calculation. We also provide the information to userspace, but it has dubious value there too. This patch switches page table accounting to single counter. mm->pgtables_bytes is now used to account all page table levels. We use bytes, because page table size for different levels of page table tree may be different. The change has user-visible effect: we don't have VmPMD and VmPUD reported in /proc/[pid]/status. Not sure if anybody uses them. (As alternative, we can always report 0 kB for them.) OOM-killer report is also slightly changed: we now report pgtables_bytes instead of nr_ptes, nr_pmd, nr_puds. Apart from reducing number of counters per-mm, the benefit is that we now calculate oom_badness() more correctly for machines which have different size of page tables depending on level or where page tables are less than a page in size. The only downside can be debuggability because we do not know which page table level could leak. But I do not remember many bugs that would be caught by separate counters so I wouldn't lose sleep over this. [akpm@linux-foundation.org: fix mm/huge_memory.c] Link: http://lkml.kernel.org/r/20171006100651.44742-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> [kirill.shutemov@linux.intel.com: fix build] Link: http://lkml.kernel.org/r/20171016150113.ikfxy3e7zzfvsr4w@black.fi.intel.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Kirill A. Shutemov
|
c4812909f5 |
mm: introduce wrappers to access mm->nr_ptes
Let's add wrappers for ->nr_ptes with the same interface as for nr_pmd and nr_pud. The patch also makes nr_ptes accounting dependent onto CONFIG_MMU. Page table accounting doesn't make sense if you don't have page tables. It's preparation for consolidation of page-table counters in mm_struct. Link: http://lkml.kernel.org/r/20171006100651.44742-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Kirill A. Shutemov
|
b4e98d9ac7 |
mm: account pud page tables
On a machine with 5-level paging support a process can allocate
significant amount of memory and stay unnoticed by oom-killer and memory
cgroup. The trick is to allocate a lot of PUD page tables. We don't
account PUD page tables, only PMD and PTE.
We already addressed the same issue for PMD page tables, see commit
|
||
Yang Shi
|
852d8be0ad |
mm: oom: show unreclaimable slab info when unreclaimable slabs > user memory
The kernel may panic when an oom happens without killable process sometimes it is caused by huge unreclaimable slabs used by kernel. Although kdump could help debug such problem, however, kdump is not available on all architectures and it might be malfunction sometime. And, since kernel already panic it is worthy capturing such information in dmesg to aid touble shooting. Print out unreclaimable slab info (used size and total size) which actual memory usage is not zero (num_objs * size != 0) when unreclaimable slabs amount is greater than total user memory (LRU pages). The output looks like: Unreclaimable slab info: Name Used Total rpc_buffers 31KB 31KB rpc_tasks 7KB 7KB ebitmap_node 1964KB 1964KB avtab_node 5024KB 5024KB xfs_buf 1402KB 1402KB xfs_ili 134KB 134KB xfs_efi_item 115KB 115KB xfs_efd_item 115KB 115KB xfs_buf_item 134KB 134KB xfs_log_item_desc 342KB 342KB xfs_trans 1412KB 1412KB xfs_ifork 212KB 212KB [yang.s@alibaba-inc.com: v11] Link: http://lkml.kernel.org/r/1507656303-103845-4-git-send-email-yang.s@alibaba-inc.com Link: http://lkml.kernel.org/r/1507152550-46205-4-git-send-email-yang.s@alibaba-inc.com Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Michal Hocko
|
4d4bbd8526 |
mm, oom_reaper: skip mm structs with mmu notifiers
Andrea has noticed that the oom_reaper doesn't invalidate the range via
mmu notifiers (mmu_notifier_invalidate_range_start/end) and that can
corrupt the memory of the kvm guest for example.
tlb_flush_mmu_tlbonly already invokes mmu notifiers but that is not
sufficient as per Andrea:
"mmu_notifier_invalidate_range cannot be used in replacement of
mmu_notifier_invalidate_range_start/end. For KVM
mmu_notifier_invalidate_range is a noop and rightfully so. A MMU
notifier implementation has to implement either ->invalidate_range
method or the invalidate_range_start/end methods, not both. And if you
implement invalidate_range_start/end like KVM is forced to do, calling
mmu_notifier_invalidate_range in common code is a noop for KVM.
For those MMU notifiers that can get away only implementing
->invalidate_range, the ->invalidate_range is implicitly called by
mmu_notifier_invalidate_range_end(). And only those secondary MMUs
that share the same pagetable with the primary MMU (like AMD iommuv2)
can get away only implementing ->invalidate_range"
As the callback is allowed to sleep and the implementation is out of
hand of the MM it is safer to simply bail out if there is an mmu
notifier registered. In order to not fail too early make the
mm_has_notifiers check under the oom_lock and have a little nap before
failing to give the current oom victim some more time to exit.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20170913113427.2291-1-mhocko@kernel.org
Fixes:
|
||
Andrea Arcangeli
|
2129258024 |
mm: oom: let oom_reap_task and exit_mmap run concurrently
This is purely required because exit_aio() may block and exit_mmap() may
never start, if the oom_reap_task cannot start running on a mm with
mm_users == 0.
At the same time if the OOM reaper doesn't wait at all for the memory of
the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would
generate a spurious OOM kill.
If it wasn't because of the exit_aio or similar blocking functions in
the last mmput, it would be enough to change the oom_reap_task() in the
case it finds mm_users == 0, to wait for a timeout or to wait for
__mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the
problem here so the concurrency of exit_mmap and oom_reap_task is
apparently warranted.
It's a non standard runtime, exit_mmap() runs without mmap_sem, and
oom_reap_task runs with the mmap_sem for reading as usual (kind of
MADV_DONTNEED).
The race between the two is solved with a combination of
tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP
(serialized by a dummy down_write/up_write cycle on the same lines of
the ksm_exit method).
If the oom_reap_task() may be running concurrently during exit_mmap,
exit_mmap will wait it to finish in down_write (before taking down mm
structures that would make the oom_reap_task fail with use after free).
If exit_mmap comes first, oom_reap_task() will skip the mm if
MMF_OOM_SKIP is already set and in turn all memory is already freed and
furthermore the mm data structures may already have been taken down by
free_pgtables.
[aarcange@redhat.com: incremental one liner]
Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com
[rientjes@google.com: remove unused mmput_async]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com
[aarcange@redhat.com: microoptimization]
Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com
Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com
Fixes:
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Michal Hocko
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cd04ae1e2d |
mm, oom: do not rely on TIF_MEMDIE for memory reserves access
For ages we have been relying on TIF_MEMDIE thread flag to mark OOM
victims and then, among other things, to give these threads full access
to memory reserves. There are few shortcomings of this implementation,
though.
First of all and the most serious one is that the full access to memory
reserves is quite dangerous because we leave no safety room for the
system to operate and potentially do last emergency steps to move on.
Secondly this flag is per task_struct while the OOM killer operates on
mm_struct granularity so all processes sharing the given mm are killed.
Giving the full access to all these task_structs could lead to a quick
memory reserves depletion. We have tried to reduce this risk by giving
TIF_MEMDIE only to the main thread and the currently allocating task but
that doesn't really solve this problem while it surely opens up a room
for corner cases - e.g. GFP_NO{FS,IO} requests might loop inside the
allocator without access to memory reserves because a particular thread
was not the group leader.
Now that we have the oom reaper and that all oom victims are reapable
after
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Roman Gushchin
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422580c3ce |
mm/oom_kill.c: add tracepoints for oom reaper-related events
During the debugging of the problem described in https://lkml.org/lkml/2017/5/17/542 and fixed by Tetsuo Handa in https://lkml.org/lkml/2017/5/19/383 , I've found that the existing debug output is not really useful to understand issues related to the oom reaper. So, I assume, that adding some tracepoints might help with debugging of similar issues. Trace the following events: 1) a process is marked as an oom victim, 2) a process is added to the oom reaper list, 3) the oom reaper starts reaping process's mm, 4) the oom reaper finished reaping, 5) the oom reaper skips reaping. How it works in practice? Below is an example which show how the problem mentioned above can be found: one process is added twice to the oom_reaper list: $ cd /sys/kernel/debug/tracing $ echo "oom:mark_victim" > set_event $ echo "oom:wake_reaper" >> set_event $ echo "oom:skip_task_reaping" >> set_event $ echo "oom:start_task_reaping" >> set_event $ echo "oom:finish_task_reaping" >> set_event $ cat trace_pipe allocate-502 [001] .... 91.836405: mark_victim: pid=502 allocate-502 [001] .N.. 91.837356: wake_reaper: pid=502 allocate-502 [000] .N.. 91.871149: wake_reaper: pid=502 oom_reaper-23 [000] .... 91.871177: start_task_reaping: pid=502 oom_reaper-23 [000] .N.. 91.879511: finish_task_reaping: pid=502 oom_reaper-23 [000] .... 91.879580: skip_task_reaping: pid=502 Link: http://lkml.kernel.org/r/20170530185231.GA13412@castle Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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8e675f7af5 |
mm/oom_kill: count global and memory cgroup oom kills
Show count of oom killer invocations in /proc/vmstat and count of processes killed in memory cgroup in knob "memory.events" (in memory.oom_control for v1 cgroup). Also describe difference between "oom" and "oom_kill" in memory cgroup documentation. Currently oom in memory cgroup kills tasks iff shortage has happened inside page fault. These counters helps in monitoring oom kills - for now the only way is grepping for magic words in kernel log. [akpm@linux-foundation.org: fix for mem_cgroup_count_vm_event() rename] [akpm@linux-foundation.org: fix comment, per Konstantin] Link: http://lkml.kernel.org/r/149570810989.203600.9492483715840752937.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Roman Guschin <guroan@gmail.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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d75da004c7 |
oom: improve oom disable handling
Tetsuo has reported that sysrq triggered OOM killer will print a misleading information when no tasks are selected: sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled The real reason is that there are no eligible tasks for the OOM killer to select but since commit |
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Ingo Molnar
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299300258d |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Ingo Molnar
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f7ccbae45c |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/coredump.h>
We are going to split <linux/sched/coredump.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/coredump.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Ingo Molnar
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6e84f31522 |
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h>
We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/mm.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. The APIs that are going to be moved first are: mm_alloc() __mmdrop() mmdrop() mmdrop_async_fn() mmdrop_async() mmget_not_zero() mmput() mmput_async() get_task_mm() mm_access() mm_release() Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Vegard Nossum
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f1f1007644 |
mm: add new mmgrab() helper
Apart from adding the helper function itself, the rest of the kernel is converted mechanically using: git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/' git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/' This is needed for a later patch that hooks into the helper, but might be a worthwhile cleanup on its own. (Michal Hocko provided most of the kerneldoc comment.) Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.com Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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David Rientjes
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299c517adb |
mm, oom: header nodemask is NULL when cpusets are disabled
Commit
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Kirill A. Shutemov
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235190738a |
oom-reaper: use madvise_dontneed() logic to decide if unmap the VMA
Logic on whether we can reap pages from the VMA should match what we have in madvise_dontneed(). In particular, we should skip, VM_PFNMAP VMAs, but we don't now. Let's just extract condition on which we can shoot down pagesi from a VMA with MADV_DONTNEED into separate function and use it in both places. Link: http://lkml.kernel.org/r/20170118122429.43661-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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3e8715fdc0 |
mm: drop zap_details::check_swap_entries
detail == NULL would give the same functionality as .check_swap_entries==true. Link: http://lkml.kernel.org/r/20170118122429.43661-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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da162e9368 |
mm: drop zap_details::ignore_dirty
The only user of ignore_dirty is oom-reaper. But it doesn't really use it. ignore_dirty only has effect on file pages mapped with dirty pte. But oom-repear skips shared VMAs, so there's no way we can dirty file pte in them. Link: http://lkml.kernel.org/r/20170118122429.43661-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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06ad276ac1 |
mm, oom: do not enforce OOM killer for __GFP_NOFAIL automatically
__alloc_pages_may_oom makes sure to skip the OOM killer depending on the
allocation request. This includes lowmem requests, costly high order
requests and others. For a long time __GFP_NOFAIL acted as an override
for all those rules. This is not documented and it can be quite
surprising as well. E.g. GFP_NOFS requests are not invoking the OOM
killer but GFP_NOFS|__GFP_NOFAIL does so if we try to convert some of
the existing open coded loops around allocator to nofail request (and we
have done that in the past) then such a change would have a non trivial
side effect which is far from obvious. Note that the primary motivation
for skipping the OOM killer is to prevent from pre-mature invocation.
The exception has been added by commit
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Michal Hocko
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9af744d743 |
lib/show_mem.c: teach show_mem to work with the given nodemask
show_mem() allows to filter out node specific data which is irrelevant to the allocation request via SHOW_MEM_FILTER_NODES. The filtering is done in skip_free_areas_node which skips all nodes which are not in the mems_allowed of the current process. This works most of the time as expected because the nodemask shouldn't be outside of the allocating task but there are some exceptions. E.g. memory hotplug might want to request allocations from outside of the allowed nodes (see new_node_page). Get rid of this hardcoded behavior and push the allocation mask down the show_mem path and use it instead of cpuset_current_mems_allowed. NULL nodemask is interpreted as cpuset_current_mems_allowed. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170117091543.25850-5-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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82e7d3abec |
oom: print nodemask in the oom report
We have received a hard to explain oom report from a customer. The oom triggered regardless there is a lot of free memory: PoolThread invoked oom-killer: gfp_mask=0x280da, order=0, oom_adj=0, oom_score_adj=0 PoolThread cpuset=/ mems_allowed=0-7 Pid: 30055, comm: PoolThread Tainted: G E X 3.0.101-80-default #1 Call Trace: dump_trace+0x75/0x300 dump_stack+0x69/0x6f dump_header+0x8e/0x110 oom_kill_process+0xa6/0x350 out_of_memory+0x2b7/0x310 __alloc_pages_slowpath+0x7dd/0x820 __alloc_pages_nodemask+0x1e9/0x200 alloc_pages_vma+0xe1/0x290 do_anonymous_page+0x13e/0x300 do_page_fault+0x1fd/0x4c0 page_fault+0x25/0x30 [...] active_anon:1135959151 inactive_anon:1051962 isolated_anon:0 active_file:13093 inactive_file:222506 isolated_file:0 unevictable:262144 dirty:2 writeback:0 unstable:0 free:432672819 slab_reclaimable:7917 slab_unreclaimable:95308 mapped:261139 shmem:166297 pagetables:2228282 bounce:0 [...] Node 0 DMA free:15896kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15672kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes lowmem_reserve[]: 0 2892 775542 775542 Node 0 DMA32 free:2783784kB min:28kB low:32kB high:40kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:2961572kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes lowmem_reserve[]: 0 0 772650 772650 Node 0 Normal free:8120kB min:8160kB low:10200kB high:12240kB active_anon:779334960kB inactive_anon:2198744kB active_file:0kB inactive_file:180kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:791193600kB mlocked:131072kB dirty:0kB writeback:0kB mapped:372940kB shmem:361480kB slab_reclaimable:4536kB slab_unreclaimable:68472kB kernel_stack:10104kB pagetables:1414820kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:2280 all_unreclaimable? yes lowmem_reserve[]: 0 0 0 0 Node 1 Normal free:476718144kB min:8192kB low:10240kB high:12288kB active_anon:307623696kB inactive_anon:283620kB active_file:10392kB inactive_file:69908kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:4kB writeback:0kB mapped:257208kB shmem:189896kB slab_reclaimable:3868kB slab_unreclaimable:44756kB kernel_stack:1848kB pagetables:1369432kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 2 Normal free:386002452kB min:8192kB low:10240kB high:12288kB active_anon:398563752kB inactive_anon:68184kB active_file:10292kB inactive_file:29936kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:32084kB shmem:776kB slab_reclaimable:6888kB slab_unreclaimable:60056kB kernel_stack:8208kB pagetables:1282880kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 3 Normal free:196406760kB min:8192kB low:10240kB high:12288kB active_anon:587445640kB inactive_anon:164396kB active_file:5716kB inactive_file:709844kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:291776kB shmem:111416kB slab_reclaimable:5152kB slab_unreclaimable:44516kB kernel_stack:2168kB pagetables:1455956kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 4 Normal free:425338880kB min:8192kB low:10240kB high:12288kB active_anon:359695204kB inactive_anon:43216kB active_file:5748kB inactive_file:14772kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:24708kB shmem:1120kB slab_reclaimable:1884kB slab_unreclaimable:41060kB kernel_stack:1856kB pagetables:1100208kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 5 Normal free:11140kB min:8192kB low:10240kB high:12288kB active_anon:784240872kB inactive_anon:1217164kB active_file:28kB inactive_file:48kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:11408kB shmem:0kB slab_reclaimable:2008kB slab_unreclaimable:49220kB kernel_stack:1360kB pagetables:531600kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1202 all_unreclaimable? yes lowmem_reserve[]: 0 0 0 0 Node 6 Normal free:243395332kB min:8192kB low:10240kB high:12288kB active_anon:542015544kB inactive_anon:40208kB active_file:968kB inactive_file:8484kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:19992kB shmem:496kB slab_reclaimable:1672kB slab_unreclaimable:37052kB kernel_stack:2088kB pagetables:750264kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 7 Normal free:10768kB min:8192kB low:10240kB high:12288kB active_anon:784916936kB inactive_anon:192316kB active_file:19228kB inactive_file:56852kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:4kB writeback:0kB mapped:34440kB shmem:4kB slab_reclaimable:5660kB slab_unreclaimable:36100kB kernel_stack:1328kB pagetables:1007968kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 So all nodes but Node 0 have a lot of free memory which should suggest that there is an available memory especially when mems_allowed=0-7. One could speculate that a massive process has managed to terminate and free up a lot of memory while racing with the above allocation request. Although this is highly unlikely it cannot be ruled out. A further debugging, however shown that the faulting process had mempolicy (not cpuset) to bind to Node 0. We cannot see that information from the report though. mems_allowed turned out to be more confusing than really helpful. Fix this by always priting the nodemask. It is either mempolicy mask (and non-null) or the one defined by the cpusets. The new output for the above oom report would be PoolThread invoked oom-killer: gfp_mask=0x280da(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=0, order=0, oom_adj=0, oom_score_adj=0 This patch doesn't touch show_mem and the node filtering based on the cpuset node mask because mempolicy is always a subset of cpusets and seeing the full cpuset oom context might be helpful for tunning more specific mempolicies inside cpusets (e.g. when they turn out to be too restrictive). To prevent from ugly ifdefs the mask is printed even for !NUMA configurations but this should be OK (a single node will be printed). Link: http://lkml.kernel.org/r/20160930214146.28600-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Sellami Abdelkader <abdelkader.sellami@sap.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Sellami Abdelkader <abdelkader.sellami@sap.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
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a104808e21 |
mm: don't emit warning from pagefault_out_of_memory()
Commit
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Michal Hocko
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9254990fb9 |
oom: warn if we go OOM for higher order and compaction is disabled
Since the lumpy reclaim is gone there is no source of higher order pages if CONFIG_COMPACTION=n except for the order-0 pages reclaim which is unreliable for that purpose to say the least. Hitting an OOM for !costly higher order requests is therefore all not that hard to imagine. We are trying hard to not invoke OOM killer as much as possible but there is simply no reliable way to detect whether more reclaim retries make sense. Disabling COMPACTION is not widespread but it seems that some users might have disable the feature without realizing full consequences (mostly along with disabling THP because compaction used to be THP mainly thing). This patch just adds a note if the OOM killer was triggered by higher order request with compaction disabled. This will help us identifying possible misconfiguration right from the oom report which is easier than to always keep in mind that somebody might have disabled COMPACTION without a good reason. Link: http://lkml.kernel.org/r/20160830111632.GD23963@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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1b51e65eab |
oom, oom_reaper: allow to reap mm shared by the kthreads
oom reaper was skipped for an mm which is shared with the kernel thread (aka use_mm()). The primary concern was that such a kthread might want to read from the userspace memory and see zero page as a result of the oom reaper action. This is no longer a problem after "mm: make sure that kthreads will not refault oom reaped memory" because any attempt to fault in when the MMF_UNSTABLE is set will result in SIGBUS and so the target user should see an error. This means that we can finally allow oom reaper also to tasks which share their mm with kthreads. Link: http://lkml.kernel.org/r/1472119394-11342-10-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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3f70dc38ce |
mm: make sure that kthreads will not refault oom reaped memory
There are only few use_mm() users in the kernel right now. Most of them write to the target memory but vhost driver relies on copy_from_user/get_user from a kernel thread context. This makes it impossible to reap the memory of an oom victim which shares the mm with the vhost kernel thread because it could see a zero page unexpectedly and theoretically make an incorrect decision visible outside of the killed task context. To quote Michael S. Tsirkin: : Getting an error from __get_user and friends is handled gracefully. : Getting zero instead of a real value will cause userspace : memory corruption. The vhost kernel thread is bound to an open fd of the vhost device which is not tight to the mm owner life cycle in general. The device fd can be inherited or passed over to another process which means that we really have to be careful about unexpected memory corruption because unlike for normal oom victims the result will be visible outside of the oom victim context. Make sure that no kthread context (users of use_mm) can ever see corrupted data because of the oom reaper and hook into the page fault path by checking MMF_UNSTABLE mm flag. __oom_reap_task_mm will set the flag before it starts unmapping the address space while the flag is checked after the page fault has been handled. If the flag is set then SIGBUS is triggered so any g-u-p user will get a error code. Regular tasks do not need this protection because all which share the mm are killed when the mm is reaped and so the corruption will not outlive them. This patch shouldn't have any visible effect at this moment because the OOM killer doesn't invoke oom reaper for tasks with mm shared with kthreads yet. Link: http://lkml.kernel.org/r/1472119394-11342-9-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: "Michael S. Tsirkin" <mst@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
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38531201c1 |
mm, oom: enforce exit_oom_victim on current task
There are no users of exit_oom_victim on !current task anymore so enforce the API to always work on the current. Link: http://lkml.kernel.org/r/1472119394-11342-8-git-send-email-mhocko@kernel.org Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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7d2e7a22cf |
oom, suspend: fix oom_killer_disable vs. pm suspend properly
Commit
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Michal Hocko
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862e3073b3 |
mm, oom: get rid of signal_struct::oom_victims
After "oom: keep mm of the killed task available" we can safely detect an oom victim by checking task->signal->oom_mm so we do not need the signal_struct counter anymore so let's get rid of it. This alone wouldn't be sufficient for nommu archs because exit_oom_victim doesn't hide the process from the oom killer anymore. We can, however, mark the mm with a MMF flag in __mmput. We can reuse MMF_OOM_REAPED and rename it to a more generic MMF_OOM_SKIP. Link: http://lkml.kernel.org/r/1472119394-11342-6-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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26db62f179 |
oom: keep mm of the killed task available
oom_reap_task has to call exit_oom_victim in order to make sure that the
oom vicim will not block the oom killer for ever. This is, however,
opening new problems (e.g oom_killer_disable exclusion - see commit
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Tetsuo Handa
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8496afaba9 |
mm,oom_reaper: do not attempt to reap a task twice
"mm, oom_reaper: do not attempt to reap a task twice" tried to give the OOM reaper one more chance to retry using MMF_OOM_NOT_REAPABLE flag. But the usefulness of the flag is rather limited and actually never shown in practice. If the flag is set, it means that the holder of mm->mmap_sem cannot call up_write() due to presumably being blocked at unkillable wait waiting for other thread's memory allocation. But since one of threads sharing that mm will queue that mm immediately via task_will_free_mem() shortcut (otherwise, oom_badness() will select the same mm again due to oom_score_adj value unchanged), retrying MMF_OOM_NOT_REAPABLE mm is unlikely helpful. Let's always set MMF_OOM_REAPED. Link: http://lkml.kernel.org/r/1472119394-11342-3-git-send-email-mhocko@kernel.org Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
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7ebffa4555 |
mm,oom_reaper: reduce find_lock_task_mm() usage
Patch series "fortify oom killer even more", v2. This patch (of 9): __oom_reap_task() can be simplified a bit if it receives a valid mm from oom_reap_task() which also uses that mm when __oom_reap_task() failed. We can drop one find_lock_task_mm() call and also make the __oom_reap_task() code flow easier to follow. Moreover, this will make later patch in the series easier to review. Pinning mm's mm_count for longer time is not really harmful because this will not pin much memory. This patch doesn't introduce any functional change. Link: http://lkml.kernel.org/r/1472119394-11342-2-git-send-email-mhocko@kernel.org Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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5870c2e1d7 |
mm/oom_kill.c: fix task_will_free_mem() comment
Attempt to demystify the task_will_free_mem() loop. Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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7c5f64f844 |
mm: oom: deduplicate victim selection code for memcg and global oom
When selecting an oom victim, we use the same heuristic for both memory cgroup and global oom. The only difference is the scope of tasks to select the victim from. So we could just export an iterator over all memcg tasks and keep all oom related logic in oom_kill.c, but instead we duplicate pieces of it in memcontrol.c reusing some initially private functions of oom_kill.c in order to not duplicate all of it. That looks ugly and error prone, because any modification of select_bad_process should also be propagated to mem_cgroup_out_of_memory. Let's rework this as follows: keep all oom heuristic related code private to oom_kill.c and make oom_kill.c use exported memcg functions when it's really necessary (like in case of iterating over memcg tasks). Link: http://lkml.kernel.org/r/1470056933-7505-1-git-send-email-vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Geert Uytterhoeven
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f33e6f0671 |
mm, oom: fix uninitialized ret in task_will_free_mem()
mm/oom_kill.c: In function `task_will_free_mem':
mm/oom_kill.c:767: warning: `ret' may be used uninitialized in this function
If __task_will_free_mem() is never called inside the for_each_process()
loop, ret will not be initialized.
Fixes:
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Michal Hocko
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091f362c53 |
mm, oom: tighten task_will_free_mem() locking
"mm, oom: fortify task_will_free_mem" has dropped task_lock around task_will_free_mem in oom_kill_process bacause it assumed that a potential race when the selected task exits will not be a problem as the oom_reaper will call exit_oom_victim. Tetsuo was objecting that nommu doesn't have oom_reaper so the race would be still possible. The code would be racy and lockup prone theoretically in other aspects without the oom reaper anyway so I didn't considered this a big deal. But it seems that further changes I am planning in this area will benefit from stable task->mm in this path as well. So let's drop find_lock_task_mm from task_will_free_mem and call it from under task_lock as we did previously. Just pull the task->mm != NULL check inside the function. Link: http://lkml.kernel.org/r/1467201562-6709-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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a373966d1f |
mm, oom: hide mm which is shared with kthread or global init
The only case where the oom_reaper is not triggered for the oom victim is when it shares the memory with a kernel thread (aka use_mm) or with the global init. After "mm, oom: skip vforked tasks from being selected" the victim cannot be a vforked task of the global init so we are left with clone(CLONE_VM) (without CLONE_SIGHAND). use_mm() users are quite rare as well. In order to help forward progress for the OOM killer, make sure that this really rare case will not get in the way - we do this by hiding the mm from the oom killer by setting MMF_OOM_REAPED flag for it. oom_scan_process_thread will ignore any TIF_MEMDIE task if it has MMF_OOM_REAPED flag set to catch these oom victims. After this patch we should guarantee forward progress for the OOM killer even when the selected victim is sharing memory with a kernel thread or global init as long as the victims mm is still alive. Link: http://lkml.kernel.org/r/1466426628-15074-11-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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11a410d516 |
mm, oom_reaper: do not attempt to reap a task more than twice
oom_reaper relies on the mmap_sem for read to do its job. Many places which might block readers have been converted to use down_write_killable and that has reduced chances of the contention a lot. Some paths where the mmap_sem is held for write can take other locks and they might either be not prepared to fail due to fatal signal pending or too impractical to be changed. This patch introduces MMF_OOM_NOT_REAPABLE flag which gets set after the first attempt to reap a task's mm fails. If the flag is present after the failure then we set MMF_OOM_REAPED to hide this mm from the oom killer completely so it can go and chose another victim. As a result a risk of OOM deadlock when the oom victim would be blocked indefinetly and so the oom killer cannot make any progress should be mitigated considerably while we still try really hard to perform all reclaim attempts and stay predictable in the behavior. Link: http://lkml.kernel.org/r/1466426628-15074-10-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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696453e666 |
mm, oom: task_will_free_mem should skip oom_reaped tasks
The 0-day robot has encountered the following: Out of memory: Kill process 3914 (trinity-c0) score 167 or sacrifice child Killed process 3914 (trinity-c0) total-vm:55864kB, anon-rss:1512kB, file-rss:1088kB, shmem-rss:25616kB oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26488kB oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26900kB oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26900kB oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:27296kB oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:28148kB oom_reaper is trying to reap the same task again and again. This is possible only when the oom killer is bypassed because of task_will_free_mem because we skip over tasks with MMF_OOM_REAPED already set during select_bad_process. Teach task_will_free_mem to skip over MMF_OOM_REAPED tasks as well because they will be unlikely to free anything more. Analyzed by Tetsuo Handa. Link: http://lkml.kernel.org/r/1466426628-15074-9-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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1af8bb4326 |
mm, oom: fortify task_will_free_mem()
task_will_free_mem is rather weak. It doesn't really tell whether the
task has chance to drop its mm.
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Michal Hocko
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97fd49c235 |
mm, oom: kill all tasks sharing the mm
Currently oom_kill_process skips both the oom reaper and SIG_KILL if a process sharing the same mm is unkillable via OOM_ADJUST_MIN. After "mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj" all such processes are sharing the same value so we shouldn't see such a task at all (oom_badness would rule them out). We can still encounter oom disabled vforked task which has to be killed as well if we want to have other tasks sharing the mm reapable because it can access the memory before doing exec. Killing such a task should be acceptable because it is highly unlikely it has done anything useful because it cannot modify any memory before it calls exec. An alternative would be to keep the task alive and skip the oom reaper and risk all the weird corner cases where the OOM killer cannot make forward progress because the oom victim hung somewhere on the way to exit. [rientjes@google.com - drop printk when OOM_SCORE_ADJ_MIN killed task the setting is inherently racy and we cannot do much about it without introducing locks in hot paths] Link: http://lkml.kernel.org/r/1466426628-15074-7-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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b18dc5f291 |
mm, oom: skip vforked tasks from being selected
vforked tasks are not really sitting on any memory. They are sharing the mm with parent until they exec into a new code. Until then it is just pinning the address space. OOM killer will kill the vforked task along with its parent but we still can end up selecting vforked task when the parent wouldn't be selected. E.g. init doing vfork to launch a task or vforked being a child of oom unkillable task with an updated oom_score_adj to be killable. Add a new helper to check whether a task is in the vfork sharing memory with its parent and use it in oom_badness to skip over these tasks. Link: http://lkml.kernel.org/r/1466426628-15074-6-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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44a70adec9 |
mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj
oom_score_adj is shared for the thread groups (via struct signal) but this is not sufficient to cover processes sharing mm (CLONE_VM without CLONE_SIGHAND) and so we can easily end up in a situation when some processes update their oom_score_adj and confuse the oom killer. In the worst case some of those processes might hide from the oom killer altogether via OOM_SCORE_ADJ_MIN while others are eligible. OOM killer would then pick up those eligible but won't be allowed to kill others sharing the same mm so the mm wouldn't release the mm and so the memory. It would be ideal to have the oom_score_adj per mm_struct because that is the natural entity OOM killer considers. But this will not work because some programs are doing vfork() set_oom_adj() exec() We can achieve the same though. oom_score_adj write handler can set the oom_score_adj for all processes sharing the same mm if the task is not in the middle of vfork. As a result all the processes will share the same oom_score_adj. The current implementation is rather pessimistic and checks all the existing processes by default if there is more than 1 holder of the mm but we do not have any reliable way to check for external users yet. Link: http://lkml.kernel.org/r/1466426628-15074-5-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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e5e3f4c4f0 |
mm, oom_reaper: make sure that mmput_async is called only when memory was reaped
Tetsuo is worried that mmput_async might still lead to a premature new oom victim selection due to the following race: __oom_reap_task exit_mm find_lock_task_mm atomic_inc(mm->mm_users) # = 2 task_unlock task_lock task->mm = NULL up_read(&mm->mmap_sem) < somebody write locks mmap_sem > task_unlock mmput atomic_dec_and_test # = 1 exit_oom_victim down_read_trylock # failed - no reclaim mmput_async # Takes unpredictable amount of time < new OOM situation > the final __mmput will be executed in the delayed context which might happen far in the future. Such a race is highly unlikely because the write holder of mmap_sem would have to be an external task (all direct holders are already killed or exiting) and it usually have to pin mm_users in order to do anything reasonable. We can, however, make sure that the mmput_async is only called when we do not back off and reap some memory. That would reduce the impact of the delayed __mmput because the real content would be already freed. Pin mm_count to keep it alive after we drop task_lock and before we try to get mmap_sem. If the mmap_sem succeeds we can try to grab mm_users reference and then go on with unmapping the address space. It is not clear whether this race is possible at all but it is better to be more robust and do not pin mm_users unless we are sure we are actually doing some real work during __oom_reap_task. Link: http://lkml.kernel.org/r/1465306987-30297-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
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fbe84a09da |
mm,oom: remove unused argument from oom_scan_process_thread().
oom_scan_process_thread() does not use totalpages argument. oom_badness() uses it. Link: http://lkml.kernel.org/r/1463796041-7889-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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2a966b77ae |
mm: oom: add memcg to oom_control
It's a part of oom context just like allocation order and nodemask, so let's move it to oom_control instead of passing it in the argument list. Link: http://lkml.kernel.org/r/40e03fd7aaf1f55c75d787128d6d17c5a71226c2.1464358556.git.vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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798fd75695 |
mm: zap ZONE_OOM_LOCKED
Not used since oom_lock was instroduced. Link: http://lkml.kernel.org/r/1464358093-22663-1-git-send-email-vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tetsuo Handa
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9df10fb7b8 |
oom_reaper: avoid pointless atomic_inc_not_zero usage.
Since commit
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Tetsuo Handa
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491a1c65ae |
mm,oom_reaper: don't call mmput_async() without atomic_inc_not_zero()
Commit
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Michal Hocko
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cbdcf7f789 |
mm, oom_reaper: do not use siglock in try_oom_reaper()
Oleg has noted that siglock usage in try_oom_reaper is both pointless
and dangerous. signal_group_exit can be checked lockless. The problem
is that sighand becomes NULL in __exit_signal so we can crash.
Fixes:
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Michal Hocko
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e2fe14564d |
oom_reaper: close race with exiting task
Tetsuo has reported:
Out of memory: Kill process 443 (oleg's-test) score 855 or sacrifice child
Killed process 443 (oleg's-test) total-vm:493248kB, anon-rss:423880kB, file-rss:4kB, shmem-rss:0kB
sh invoked oom-killer: gfp_mask=0x24201ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD), order=0, oom_score_adj=0
sh cpuset=/ mems_allowed=0
CPU: 2 PID: 1 Comm: sh Not tainted 4.6.0-rc7+ #51
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
Call Trace:
dump_stack+0x85/0xc8
dump_header+0x5b/0x394
oom_reaper: reaped process 443 (oleg's-test), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
In other words:
__oom_reap_task exit_mm
atomic_inc_not_zero
tsk->mm = NULL
mmput
atomic_dec_and_test # > 0
exit_oom_victim # New victim will be
# selected
<OOM killer invoked>
# no TIF_MEMDIE task so we can select a new one
unmap_page_range # to release the memory
The race exists even without the oom_reaper because anybody who pins the
address space and gets preempted might race with exit_mm but oom_reaper
made this race more probable.
We can address the oom_reaper part by using oom_lock for __oom_reap_task
because this would guarantee that a new oom victim will not be selected
if the oom reaper might race with the exit path. This doesn't solve the
original issue, though, because somebody else still might be pinning
mm_users and so __mmput won't be called to release the memory but that
is not really realiably solvable because the task will get away from the
oom sight as soon as it is unhashed from the task_list and so we cannot
guarantee a new victim won't be selected.
[akpm@linux-foundation.org: fix use of unused `mm', Per Stephen]
[akpm@linux-foundation.org: coding-style fixes]
Fixes:
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Vladimir Davydov
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edd9f7230f |
mm: oom: do not reap task if there are live threads in threadgroup
If the current process is exiting, we don't invoke oom killer, instead
we give it access to memory reserves and try to reap its mm in case
nobody is going to use it. There's a mistake in the code performing
this check - we just ignore any process of the same thread group no
matter if it is exiting or not - see try_oom_reaper. Fix it.
Link: http://lkml.kernel.org/r/1464087628-7318-1-git-send-email-vdavydov@virtuozzo.com
Fixes:
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Tetsuo Handa
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f44666b046 |
mm,oom: speed up select_bad_process() loop
Since commit
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Michal Hocko
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ec8d7c14ea |
mm, oom_reaper: do not mmput synchronously from the oom reaper context
Tetsuo has properly noted that mmput slow path might get blocked waiting for another party (e.g. exit_aio waits for an IO). If that happens the oom_reaper would be put out of the way and will not be able to process next oom victim. We should strive for making this context as reliable and independent on other subsystems as much as possible. Introduce mmput_async which will perform the slow path from an async (WQ) context. This will delay the operation but that shouldn't be a problem because the oom_reaper has reclaimed the victim's address space for most cases as much as possible and the remaining context shouldn't bind too much memory anymore. The only exception is when mmap_sem trylock has failed which shouldn't happen too often. The issue is only theoretical but not impossible. Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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bb8a4b7fd1 |
mm, oom_reaper: hide oom reaped tasks from OOM killer more carefully
Commit
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