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authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-24 20:47:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-24 20:47:21 -0700
commitaefbef10e3ae6e2c6e3c54f906f10b34c73a2c66 (patch)
treeef967a568ff5e7bb52d1d3d0c61e701ad4f31c21 /kernel
parent266da6f14232638b9caafb7facf2a7333895dd05 (diff)
parent8a8c35fadfaf55629a37ef1a8ead1b8fb32581d2 (diff)
Merge branch 'akpm' (patches from Andrew)
Merge first patchbomb from Andrew Morton: - a few misc things - ocfs2 udpates - kernel/watchdog.c feature work (took ages to get right) - most of MM. A few tricky bits are held up and probably won't make 4.2. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits) mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc() mm, thp: respect MPOL_PREFERRED policy with non-local node tmpfs: truncate prealloc blocks past i_size mm/memory hotplug: print the last vmemmap region at the end of hot add memory mm/mmap.c: optimization of do_mmap_pgoff function mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan mm: kmemleak: avoid deadlock on the kmemleak object insertion error path mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup() mm: kmemleak: fix delete_object_*() race when called on the same memory block mm: kmemleak: allow safe memory scanning during kmemleak disabling memcg: convert mem_cgroup->under_oom from atomic_t to int memcg: remove unused mem_cgroup->oom_wakeups frontswap: allow multiple backends x86, mirror: x86 enabling - find mirrored memory ranges mm/memblock: allocate boot time data structures from mirrored memory mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute mm: do not ignore mapping_gfp_mask in page cache allocation paths mm/cma.c: fix typos in comments mm/oom_kill.c: print points as unsigned int mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/exit.c2
-rw-r--r--kernel/smpboot.c60
-rw-r--r--kernel/sysctl.c7
-rw-r--r--kernel/watchdog.c67
4 files changed, 129 insertions, 7 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 22fcc05dec40..185752a729f6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -436,7 +436,7 @@ static void exit_mm(struct task_struct *tsk)
mm_update_next_owner(mm);
mmput(mm);
if (test_thread_flag(TIF_MEMDIE))
- unmark_oom_victim();
+ exit_oom_victim();
}
static struct task_struct *find_alive_thread(struct task_struct *p)
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index c697f73d82d6..7c434c39f02a 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -232,7 +232,8 @@ void smpboot_unpark_threads(unsigned int cpu)
mutex_lock(&smpboot_threads_lock);
list_for_each_entry(cur, &hotplug_threads, list)
- smpboot_unpark_thread(cur, cpu);
+ if (cpumask_test_cpu(cpu, cur->cpumask))
+ smpboot_unpark_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
}
@@ -258,6 +259,15 @@ static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
{
unsigned int cpu;
+ /* Unpark any threads that were voluntarily parked. */
+ for_each_cpu_not(cpu, ht->cpumask) {
+ if (cpu_online(cpu)) {
+ struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+ if (tsk)
+ kthread_unpark(tsk);
+ }
+ }
+
/* We need to destroy also the parked threads of offline cpus */
for_each_possible_cpu(cpu) {
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
@@ -281,6 +291,10 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
unsigned int cpu;
int ret = 0;
+ if (!alloc_cpumask_var(&plug_thread->cpumask, GFP_KERNEL))
+ return -ENOMEM;
+ cpumask_copy(plug_thread->cpumask, cpu_possible_mask);
+
get_online_cpus();
mutex_lock(&smpboot_threads_lock);
for_each_online_cpu(cpu) {
@@ -313,9 +327,53 @@ void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
smpboot_destroy_threads(plug_thread);
mutex_unlock(&smpboot_threads_lock);
put_online_cpus();
+ free_cpumask_var(plug_thread->cpumask);
}
EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
+/**
+ * smpboot_update_cpumask_percpu_thread - Adjust which per_cpu hotplug threads stay parked
+ * @plug_thread: Hotplug thread descriptor
+ * @new: Revised mask to use
+ *
+ * The cpumask field in the smp_hotplug_thread must not be updated directly
+ * by the client, but only by calling this function.
+ * This function can only be called on a registered smp_hotplug_thread.
+ */
+int smpboot_update_cpumask_percpu_thread(struct smp_hotplug_thread *plug_thread,
+ const struct cpumask *new)
+{
+ struct cpumask *old = plug_thread->cpumask;
+ cpumask_var_t tmp;
+ unsigned int cpu;
+
+ if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
+ return -ENOMEM;
+
+ get_online_cpus();
+ mutex_lock(&smpboot_threads_lock);
+
+ /* Park threads that were exclusively enabled on the old mask. */
+ cpumask_andnot(tmp, old, new);
+ for_each_cpu_and(cpu, tmp, cpu_online_mask)
+ smpboot_park_thread(plug_thread, cpu);
+
+ /* Unpark threads that are exclusively enabled on the new mask. */
+ cpumask_andnot(tmp, new, old);
+ for_each_cpu_and(cpu, tmp, cpu_online_mask)
+ smpboot_unpark_thread(plug_thread, cpu);
+
+ cpumask_copy(old, new);
+
+ mutex_unlock(&smpboot_threads_lock);
+ put_online_cpus();
+
+ free_cpumask_var(tmp);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(smpboot_update_cpumask_percpu_thread);
+
static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD);
/*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b13e9d2de302..812fcc3fd390 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -872,6 +872,13 @@ static struct ctl_table kern_table[] = {
.extra2 = &one,
},
{
+ .procname = "watchdog_cpumask",
+ .data = &watchdog_cpumask_bits,
+ .maxlen = NR_CPUS,
+ .mode = 0644,
+ .proc_handler = proc_watchdog_cpumask,
+ },
+ {
.procname = "softlockup_panic",
.data = &softlockup_panic,
.maxlen = sizeof(int),
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 581a68a04c64..a6ffa43f2993 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -19,6 +19,7 @@
#include <linux/sysctl.h>
#include <linux/smpboot.h>
#include <linux/sched/rt.h>
+#include <linux/tick.h>
#include <asm/irq_regs.h>
#include <linux/kvm_para.h>
@@ -58,6 +59,12 @@ int __read_mostly sysctl_softlockup_all_cpu_backtrace;
#else
#define sysctl_softlockup_all_cpu_backtrace 0
#endif
+static struct cpumask watchdog_cpumask __read_mostly;
+unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
+
+/* Helper for online, unparked cpus. */
+#define for_each_watchdog_cpu(cpu) \
+ for_each_cpu_and((cpu), cpu_online_mask, &watchdog_cpumask)
static int __read_mostly watchdog_running;
static u64 __read_mostly sample_period;
@@ -207,7 +214,7 @@ void touch_all_softlockup_watchdogs(void)
* do we care if a 0 races with a timestamp?
* all it means is the softlock check starts one cycle later
*/
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
per_cpu(watchdog_touch_ts, cpu) = 0;
}
@@ -616,7 +623,7 @@ void watchdog_nmi_enable_all(void)
goto unlock;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_enable(cpu);
put_online_cpus();
@@ -634,7 +641,7 @@ void watchdog_nmi_disable_all(void)
goto unlock;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_disable(cpu);
put_online_cpus();
@@ -696,7 +703,7 @@ static void update_watchdog_all_cpus(void)
int cpu;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
update_watchdog(cpu);
put_online_cpus();
}
@@ -709,8 +716,12 @@ static int watchdog_enable_all_cpus(void)
err = smpboot_register_percpu_thread(&watchdog_threads);
if (err)
pr_err("Failed to create watchdog threads, disabled\n");
- else
+ else {
+ if (smpboot_update_cpumask_percpu_thread(
+ &watchdog_threads, &watchdog_cpumask))
+ pr_err("Failed to set cpumask for watchdog threads\n");
watchdog_running = 1;
+ }
} else {
/*
* Enable/disable the lockup detectors or
@@ -879,12 +890,58 @@ out:
mutex_unlock(&watchdog_proc_mutex);
return err;
}
+
+/*
+ * The cpumask is the mask of possible cpus that the watchdog can run
+ * on, not the mask of cpus it is actually running on. This allows the
+ * user to specify a mask that will include cpus that have not yet
+ * been brought online, if desired.
+ */
+int proc_watchdog_cpumask(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int err;
+
+ mutex_lock(&watchdog_proc_mutex);
+ err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
+ if (!err && write) {
+ /* Remove impossible cpus to keep sysctl output cleaner. */
+ cpumask_and(&watchdog_cpumask, &watchdog_cpumask,
+ cpu_possible_mask);
+
+ if (watchdog_running) {
+ /*
+ * Failure would be due to being unable to allocate
+ * a temporary cpumask, so we are likely not in a
+ * position to do much else to make things better.
+ */
+ if (smpboot_update_cpumask_percpu_thread(
+ &watchdog_threads, &watchdog_cpumask) != 0)
+ pr_err("cpumask update failed\n");
+ }
+ }
+ mutex_unlock(&watchdog_proc_mutex);
+ return err;
+}
+
#endif /* CONFIG_SYSCTL */
void __init lockup_detector_init(void)
{
set_sample_period();
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_enabled()) {
+ if (!cpumask_empty(tick_nohz_full_mask))
+ pr_info("Disabling watchdog on nohz_full cores by default\n");
+ cpumask_andnot(&watchdog_cpumask, cpu_possible_mask,
+ tick_nohz_full_mask);
+ } else
+ cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
+#else
+ cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
+#endif
+
if (watchdog_enabled)
watchdog_enable_all_cpus();
}