aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c24
-rw-r--r--kernel/irq/handle.c2
-rw-r--r--kernel/module.c6
-rw-r--r--kernel/sched.c2
-rw-r--r--kernel/signal.c11
-rw-r--r--kernel/spinlock.c8
6 files changed, 40 insertions, 13 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 961d74044de..00e8f257551 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -166,9 +166,8 @@ static struct super_block *cpuset_sb = NULL;
* The hooks from fork and exit, cpuset_fork() and cpuset_exit(), don't
* (usually) grab cpuset_sem. These are the two most performance
* critical pieces of code here. The exception occurs on exit(),
- * if the last task using a cpuset exits, and the cpuset was marked
- * notify_on_release. In that case, the cpuset_sem is taken, the
- * path to the released cpuset calculated, and a usermode call made
+ * when a task in a notify_on_release cpuset exits. Then cpuset_sem
+ * is taken, and if the cpuset count is zero, a usermode call made
* to /sbin/cpuset_release_agent with the name of the cpuset (path
* relative to the root of cpuset file system) as the argument.
*
@@ -1404,6 +1403,18 @@ void cpuset_fork(struct task_struct *tsk)
*
* Description: Detach cpuset from @tsk and release it.
*
+ * Note that cpusets marked notify_on_release force every task
+ * in them to take the global cpuset_sem semaphore when exiting.
+ * This could impact scaling on very large systems. Be reluctant
+ * to use notify_on_release cpusets where very high task exit
+ * scaling is required on large systems.
+ *
+ * Don't even think about derefencing 'cs' after the cpuset use
+ * count goes to zero, except inside a critical section guarded
+ * by the cpuset_sem semaphore. If you don't hold cpuset_sem,
+ * then a zero cpuset use count is a license to any other task to
+ * nuke the cpuset immediately.
+ *
**/
void cpuset_exit(struct task_struct *tsk)
@@ -1415,10 +1426,13 @@ void cpuset_exit(struct task_struct *tsk)
tsk->cpuset = NULL;
task_unlock(tsk);
- if (atomic_dec_and_test(&cs->count)) {
+ if (notify_on_release(cs)) {
down(&cpuset_sem);
- check_for_release(cs);
+ if (atomic_dec_and_test(&cs->count))
+ check_for_release(cs);
up(&cpuset_sem);
+ } else {
+ atomic_dec(&cs->count);
}
}
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 06b5a632399..436c7d93c00 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -119,8 +119,6 @@ fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
*/
desc->handler->ack(irq);
action_ret = handle_IRQ_event(irq, regs, desc->action);
- if (!noirqdebug)
- note_interrupt(irq, desc, action_ret);
desc->handler->end(irq);
return 1;
}
diff --git a/kernel/module.c b/kernel/module.c
index 5734ab09d3f..83b3d376708 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1758,6 +1758,7 @@ sys_init_module(void __user *umod,
const char __user *uargs)
{
struct module *mod;
+ mm_segment_t old_fs = get_fs();
int ret = 0;
/* Must have permission */
@@ -1775,6 +1776,9 @@ sys_init_module(void __user *umod,
return PTR_ERR(mod);
}
+ /* flush the icache in correct context */
+ set_fs(KERNEL_DS);
+
/* Flush the instruction cache, since we've played with text */
if (mod->module_init)
flush_icache_range((unsigned long)mod->module_init,
@@ -1783,6 +1787,8 @@ sys_init_module(void __user *umod,
flush_icache_range((unsigned long)mod->module_core,
(unsigned long)mod->module_core + mod->core_size);
+ set_fs(old_fs);
+
/* Now sew it into the lists. They won't access us, since
strong_try_module_get() will fail. */
stop_machine_run(__link_module, mod, NR_CPUS);
diff --git a/kernel/sched.c b/kernel/sched.c
index 0dc3158667a..66b2ed78482 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4243,7 +4243,7 @@ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *tsk)
/* No more Mr. Nice Guy. */
if (dest_cpu == NR_CPUS) {
- tsk->cpus_allowed = cpuset_cpus_allowed(tsk);
+ cpus_setall(tsk->cpus_allowed);
dest_cpu = any_online_cpu(tsk->cpus_allowed);
/*
diff --git a/kernel/signal.c b/kernel/signal.c
index 293e189d8bc..c89821b69ae 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -523,7 +523,16 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
{
int sig = 0;
- sig = next_signal(pending, mask);
+ /* SIGKILL must have priority, otherwise it is quite easy
+ * to create an unkillable process, sending sig < SIGKILL
+ * to self */
+ if (unlikely(sigismember(&pending->signal, SIGKILL))) {
+ if (!sigismember(mask, SIGKILL))
+ sig = SIGKILL;
+ }
+
+ if (likely(!sig))
+ sig = next_signal(pending, mask);
if (sig) {
if (current->notifier) {
if (sigismember(current->notifier_mask, sig)) {
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index e15ed17863f..0c3f9d8bbe1 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -294,7 +294,7 @@ EXPORT_SYMBOL(_spin_unlock_irq);
void __lockfunc _spin_unlock_bh(spinlock_t *lock)
{
_raw_spin_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_spin_unlock_bh);
@@ -318,7 +318,7 @@ EXPORT_SYMBOL(_read_unlock_irq);
void __lockfunc _read_unlock_bh(rwlock_t *lock)
{
_raw_read_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_read_unlock_bh);
@@ -342,7 +342,7 @@ EXPORT_SYMBOL(_write_unlock_irq);
void __lockfunc _write_unlock_bh(rwlock_t *lock)
{
_raw_write_unlock(lock);
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
}
EXPORT_SYMBOL(_write_unlock_bh);
@@ -354,7 +354,7 @@ int __lockfunc _spin_trylock_bh(spinlock_t *lock)
if (_raw_spin_trylock(lock))
return 1;
- preempt_enable();
+ preempt_enable_no_resched();
local_bh_enable();
return 0;
}