From b9176e2cb8372c25f6c2408931bfea37bdc75b2b Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 31 Jul 2014 09:28:32 +1000 Subject: mm, oom: remove unnecessary exit_state check The oom killer scans each process and determines whether it is eligible for oom kill or whether the oom killer should abort because of concurrent memory freeing. It will abort when an eligible process is found to have TIF_MEMDIE set, meaning it has already been oom killed and we're waiting for it to exit. Processes with task->mm == NULL should not be considered because they are either kthreads or have already detached their memory and killing them would not lead to memory freeing. That memory is only freed after exit_mm() has returned, however, and not when task->mm is first set to NULL. Clear TIF_MEMDIE after exit_mm()'s mmput() so that an oom killed process is no longer considered for oom kill, but only until exit_mm() has returned. This was fragile in the past because it relied on exit_notify() to be reached before no longer considering TIF_MEMDIE processes. Signed-off-by: David Rientjes Cc: Oleg Nesterov Signed-off-by: Andrew Morton --- kernel/exit.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index e5c4668f1799..88c6b3e42583 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -455,6 +455,7 @@ static void exit_mm(struct task_struct * tsk) task_unlock(tsk); mm_update_next_owner(mm); mmput(mm); + clear_thread_flag(TIF_MEMDIE); } /* -- cgit v1.2.3 From 6d1364482de5b71ef65afd789bc7a4956909fe8e Mon Sep 17 00:00:00 2001 From: Ionut Alexa Date: Thu, 31 Jul 2014 09:29:05 +1000 Subject: kernel/exit.c: fix coding style warnings and errors Fixed coding style warnings and errors. Signed-off-by: Ionut Alexa Signed-off-by: Andrew Morton --- kernel/exit.c | 49 ++++++++++++++++++++++++++----------------------- 1 file changed, 26 insertions(+), 23 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index 88c6b3e42583..32c58f7433a3 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -59,7 +59,7 @@ #include #include -static void exit_mm(struct task_struct * tsk); +static void exit_mm(struct task_struct *tsk); static void __unhash_process(struct task_struct *p, bool group_dead) { @@ -151,7 +151,7 @@ static void __exit_signal(struct task_struct *tsk) spin_unlock(&sighand->siglock); __cleanup_sighand(sighand); - clear_tsk_thread_flag(tsk,TIF_SIGPENDING); + clear_tsk_thread_flag(tsk, TIF_SIGPENDING); if (group_dead) { flush_sigqueue(&sig->shared_pending); tty_kref_put(tty); @@ -168,7 +168,7 @@ static void delayed_put_task_struct(struct rcu_head *rhp) } -void release_task(struct task_struct * p) +void release_task(struct task_struct *p) { struct task_struct *leader; int zap_leader; @@ -192,7 +192,8 @@ repeat: */ zap_leader = 0; leader = p->group_leader; - if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { + if (leader != p && thread_group_empty(leader) + && leader->exit_state == EXIT_ZOMBIE) { /* * If we were the last child thread and the leader has * exited already, and the leader's parent ignores SIGCHLD, @@ -241,7 +242,8 @@ struct pid *session_of_pgrp(struct pid *pgrp) * * "I ask you, have you ever known what it is to be an orphan?" */ -static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) +static int will_become_orphaned_pgrp(struct pid *pgrp, + struct task_struct *ignored_task) { struct task_struct *p; @@ -294,9 +296,9 @@ kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) struct task_struct *ignored_task = tsk; if (!parent) - /* exit: our father is in a different pgrp than - * we are and we were the only connection outside. - */ + /* exit: our father is in a different pgrp than + * we are and we were the only connection outside. + */ parent = tsk->real_parent; else /* reparent: our child is in a different pgrp than @@ -405,7 +407,7 @@ assign_new_owner: * Turn us into a lazy TLB process if we * aren't already.. */ -static void exit_mm(struct task_struct * tsk) +static void exit_mm(struct task_struct *tsk) { struct mm_struct *mm = tsk->mm; struct core_state *core_state; @@ -425,6 +427,7 @@ static void exit_mm(struct task_struct * tsk) core_state = mm->core_state; if (core_state) { struct core_thread self; + up_read(&mm->mmap_sem); self.task = tsk; @@ -566,6 +569,7 @@ static void forget_original_parent(struct task_struct *father) list_for_each_entry_safe(p, n, &father->children, sibling) { struct task_struct *t = p; + do { t->real_parent = reaper; if (t->parent == father) { @@ -599,7 +603,7 @@ static void exit_notify(struct task_struct *tsk, int group_dead) /* * This does two things: * - * A. Make init inherit all the child processes + * A. Make init inherit all the child processes * B. Check to see if any process groups have become orphaned * as a result of our exiting, and if they have any stopped * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) @@ -649,9 +653,8 @@ static void check_stack_usage(void) spin_lock(&low_water_lock); if (free < lowest_to_date) { - printk(KERN_WARNING "%s (%d) used greatest stack depth: " - "%lu bytes left\n", - current->comm, task_pid_nr(current), free); + pr_warn("%s (%d) used greatest stack depth: %lu bytes left\n", + current->comm, task_pid_nr(current), free); lowest_to_date = free; } spin_unlock(&low_water_lock); @@ -692,8 +695,7 @@ void do_exit(long code) * leave this task alone and wait for reboot. */ if (unlikely(tsk->flags & PF_EXITING)) { - printk(KERN_ALERT - "Fixing recursive fault but reboot is needed!\n"); + pr_alert("Fixing recursive fault but reboot is needed!\n"); /* * We can do this unlocked here. The futex code uses * this flag just to verify whether the pi state @@ -717,9 +719,9 @@ void do_exit(long code) raw_spin_unlock_wait(&tsk->pi_lock); if (unlikely(in_atomic())) - printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", - current->comm, task_pid_nr(current), - preempt_count()); + pr_info("note: %s[%d] exited with preempt_count %d\n", + current->comm, task_pid_nr(current), + preempt_count()); acct_update_integrals(tsk); /* sync mm's RSS info before statistics gathering */ @@ -837,7 +839,6 @@ void do_exit(long code) for (;;) cpu_relax(); /* For when BUG is null */ } - EXPORT_SYMBOL_GPL(do_exit); void complete_and_exit(struct completion *comp, long code) @@ -847,7 +848,6 @@ void complete_and_exit(struct completion *comp, long code) do_exit(code); } - EXPORT_SYMBOL(complete_and_exit); SYSCALL_DEFINE1(exit, int, error_code) @@ -870,6 +870,7 @@ do_group_exit(int exit_code) exit_code = sig->group_exit_code; else if (!thread_group_empty(current)) { struct sighand_struct *const sighand = current->sighand; + spin_lock_irq(&sighand->siglock); if (signal_group_exit(sig)) /* Another thread got here before we took the lock. */ @@ -1034,9 +1035,9 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) * as other threads in the parent group can be right * here reaping other children at the same time. * - * We use thread_group_cputime_adjusted() to get times for the thread - * group, which consolidates times for all threads in the - * group including the group leader. + * We use thread_group_cputime_adjusted() to get times for + * the thread group, which consolidates times for all threads + * in the group including the group leader. */ thread_group_cputime_adjusted(p, &tgutime, &tgstime); spin_lock_irq(&p->real_parent->sighand->siglock); @@ -1418,6 +1419,7 @@ static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk) list_for_each_entry(p, &tsk->children, sibling) { int ret = wait_consider_task(wo, 0, p); + if (ret) return ret; } @@ -1431,6 +1433,7 @@ static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk) list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { int ret = wait_consider_task(wo, 1, p); + if (ret) return ret; } -- cgit v1.2.3