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-rw-r--r--mm/oom_kill.c166
1 files changed, 74 insertions, 92 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2958fd8..4198e00 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -34,6 +34,7 @@
#include <linux/ptrace.h>
#include <linux/freezer.h>
#include <linux/ftrace.h>
+#include <linux/ratelimit.h>
#define CREATE_TRACE_POINTS
#include <trace/events/oom.h>
@@ -309,7 +310,7 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
*/
static struct task_struct *select_bad_process(unsigned int *ppoints,
unsigned long totalpages, struct mem_cgroup *memcg,
- const nodemask_t *nodemask)
+ const nodemask_t *nodemask, bool force_kill)
{
struct task_struct *g, *p;
struct task_struct *chosen = NULL;
@@ -335,7 +336,8 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
if (unlikely(frozen(p)))
__thaw_task(p);
- return ERR_PTR(-1UL);
+ if (!force_kill)
+ return ERR_PTR(-1UL);
}
if (!p->mm)
continue;
@@ -353,7 +355,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
if (p == current) {
chosen = p;
*ppoints = 1000;
- } else {
+ } else if (!force_kill) {
/*
* If this task is not being ptraced on exit,
* then wait for it to finish before killing
@@ -434,66 +436,18 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
}
#define K(x) ((x) << (PAGE_SHIFT-10))
-static int oom_kill_task(struct task_struct *p)
-{
- struct task_struct *q;
- struct mm_struct *mm;
-
- p = find_lock_task_mm(p);
- if (!p)
- return 1;
-
- /* mm cannot be safely dereferenced after task_unlock(p) */
- mm = p->mm;
-
- pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
- task_pid_nr(p), p->comm, K(p->mm->total_vm),
- K(get_mm_counter(p->mm, MM_ANONPAGES)),
- K(get_mm_counter(p->mm, MM_FILEPAGES)));
- task_unlock(p);
-
- /*
- * Kill all user processes sharing p->mm in other thread groups, if any.
- * They don't get access to memory reserves or a higher scheduler
- * priority, though, to avoid depletion of all memory or task
- * starvation. This prevents mm->mmap_sem livelock when an oom killed
- * task cannot exit because it requires the semaphore and its contended
- * by another thread trying to allocate memory itself. That thread will
- * now get access to memory reserves since it has a pending fatal
- * signal.
- */
- for_each_process(q)
- if (q->mm == mm && !same_thread_group(q, p) &&
- !(q->flags & PF_KTHREAD)) {
- if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
- continue;
-
- task_lock(q); /* Protect ->comm from prctl() */
- pr_err("Kill process %d (%s) sharing same memory\n",
- task_pid_nr(q), q->comm);
- task_unlock(q);
- force_sig(SIGKILL, q);
- }
-
- set_tsk_thread_flag(p, TIF_MEMDIE);
- force_sig(SIGKILL, p);
-
- return 0;
-}
-#undef K
-
-static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
- unsigned int points, unsigned long totalpages,
- struct mem_cgroup *memcg, nodemask_t *nodemask,
- const char *message)
+static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
+ unsigned int points, unsigned long totalpages,
+ struct mem_cgroup *memcg, nodemask_t *nodemask,
+ const char *message)
{
struct task_struct *victim = p;
struct task_struct *child;
struct task_struct *t = p;
+ struct mm_struct *mm;
unsigned int victim_points = 0;
-
- if (printk_ratelimit())
- dump_header(p, gfp_mask, order, memcg, nodemask);
+ static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
/*
* If the task is already exiting, don't alarm the sysadmin or kill
@@ -501,9 +455,12 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
*/
if (p->flags & PF_EXITING) {
set_tsk_thread_flag(p, TIF_MEMDIE);
- return 0;
+ return;
}
+ if (__ratelimit(&oom_rs))
+ dump_header(p, gfp_mask, order, memcg, nodemask);
+
task_lock(p);
pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
message, task_pid_nr(p), p->comm, points);
@@ -533,8 +490,44 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
}
} while_each_thread(p, t);
- return oom_kill_task(victim);
+ victim = find_lock_task_mm(victim);
+ if (!victim)
+ return;
+
+ /* mm cannot safely be dereferenced after task_unlock(victim) */
+ mm = victim->mm;
+ pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
+ task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
+ K(get_mm_counter(victim->mm, MM_ANONPAGES)),
+ K(get_mm_counter(victim->mm, MM_FILEPAGES)));
+ task_unlock(victim);
+
+ /*
+ * Kill all user processes sharing victim->mm in other thread groups, if
+ * any. They don't get access to memory reserves, though, to avoid
+ * depletion of all memory. This prevents mm->mmap_sem livelock when an
+ * oom killed thread cannot exit because it requires the semaphore and
+ * its contended by another thread trying to allocate memory itself.
+ * That thread will now get access to memory reserves since it has a
+ * pending fatal signal.
+ */
+ for_each_process(p)
+ if (p->mm == mm && !same_thread_group(p, victim) &&
+ !(p->flags & PF_KTHREAD)) {
+ if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
+ continue;
+
+ task_lock(p); /* Protect ->comm from prctl() */
+ pr_err("Kill process %d (%s) sharing same memory\n",
+ task_pid_nr(p), p->comm);
+ task_unlock(p);
+ force_sig(SIGKILL, p);
+ }
+
+ set_tsk_thread_flag(victim, TIF_MEMDIE);
+ force_sig(SIGKILL, victim);
}
+#undef K
/*
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
@@ -561,7 +554,8 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
}
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask)
+void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+ int order)
{
unsigned long limit;
unsigned int points = 0;
@@ -577,18 +571,13 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask)
return;
}
- check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL);
+ check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT;
read_lock(&tasklist_lock);
-retry:
- p = select_bad_process(&points, limit, memcg, NULL);
- if (!p || PTR_ERR(p) == -1UL)
- goto out;
-
- if (oom_kill_process(p, gfp_mask, 0, points, limit, memcg, NULL,
- "Memory cgroup out of memory"))
- goto retry;
-out:
+ p = select_bad_process(&points, limit, memcg, NULL, false);
+ if (p && PTR_ERR(p) != -1UL)
+ oom_kill_process(p, gfp_mask, order, points, limit, memcg, NULL,
+ "Memory cgroup out of memory");
read_unlock(&tasklist_lock);
}
#endif
@@ -700,6 +689,7 @@ static void clear_system_oom(void)
* @gfp_mask: memory allocation flags
* @order: amount of memory being requested as a power of 2
* @nodemask: nodemask passed to page allocator
+ * @force_kill: true if a task must be killed, even if others are exiting
*
* If we run out of memory, we have the choice between either
* killing a random task (bad), letting the system crash (worse)
@@ -707,7 +697,7 @@ static void clear_system_oom(void)
* don't have to be perfect here, we just have to be good.
*/
void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
- int order, nodemask_t *nodemask)
+ int order, nodemask_t *nodemask, bool force_kill)
{
const nodemask_t *mpol_mask;
struct task_struct *p;
@@ -745,33 +735,25 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
if (sysctl_oom_kill_allocating_task &&
!oom_unkillable_task(current, NULL, nodemask) &&
current->mm) {
- /*
- * oom_kill_process() needs tasklist_lock held. If it returns
- * non-zero, current could not be killed so we must fallback to
- * the tasklist scan.
- */
- if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
- NULL, nodemask,
- "Out of memory (oom_kill_allocating_task)"))
- goto out;
- }
-
-retry:
- p = select_bad_process(&points, totalpages, NULL, mpol_mask);
- if (PTR_ERR(p) == -1UL)
+ oom_kill_process(current, gfp_mask, order, 0, totalpages, NULL,
+ nodemask,
+ "Out of memory (oom_kill_allocating_task)");
goto out;
+ }
+ p = select_bad_process(&points, totalpages, NULL, mpol_mask,
+ force_kill);
/* Found nothing?!?! Either we hang forever, or we panic. */
if (!p) {
dump_header(NULL, gfp_mask, order, NULL, mpol_mask);
read_unlock(&tasklist_lock);
panic("Out of memory and no killable processes...\n");
}
-
- if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
- nodemask, "Out of memory"))
- goto retry;
- killed = 1;
+ if (PTR_ERR(p) != -1UL) {
+ oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
+ nodemask, "Out of memory");
+ killed = 1;
+ }
out:
read_unlock(&tasklist_lock);
@@ -792,7 +774,7 @@ out:
void pagefault_out_of_memory(void)
{
if (try_set_system_oom()) {
- out_of_memory(NULL, 0, 0, NULL);
+ out_of_memory(NULL, 0, 0, NULL, false);
clear_system_oom();
}
if (!test_thread_flag(TIF_MEMDIE))
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