The patch titled
cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets
has been added to the -mm tree. Its filename is
cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets
From: David Rientjes <rientjes@xxxxxxxxxx>
Kthreads that have the PF_THREAD_BOUND bit set in their flags are bound to a
specific cpu. Thus, their set of allowed cpus shall not change.
This patch prevents such threads from attaching to non-root cpusets. They do
not have mempolicies that restrict them to a subset of system nodes and, since
their cpumask may never change, they cannot use any of the features of
cpusets.
The tasks will forever be a member of the root cpuset and will be returned
when listing the tasks attached to that cpuset.
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cpuset.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff -puN kernel/cpuset.c~cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets kernel/cpuset.c
--- a/kernel/cpuset.c~cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets
+++ a/kernel/cpuset.c
@@ -1342,19 +1342,22 @@ static int cpuset_can_attach(struct cgro
struct cgroup *cont, struct task_struct *tsk)
{
struct cpuset *cs = cgroup_cs(cont);
- int ret = 0;
if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
return -ENOSPC;
- if (tsk->flags & PF_THREAD_BOUND) {
- mutex_lock(&callback_mutex);
- if (!cpumask_equal(&tsk->cpus_allowed, cs->cpus_allowed))
- ret = -EINVAL;
- mutex_unlock(&callback_mutex);
- }
+ /*
+ * Kthreads bound to specific cpus cannot be moved to a new cpuset; we
+ * cannot change their cpu affinity and isolating such threads by their
+ * set of allowed nodes is unnecessary. Thus, cpusets are not
+ * applicable for such threads. This prevents checking for success of
+ * set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
+ * be changed.
+ */
+ if (tsk->flags & PF_THREAD_BOUND)
+ return -EINVAL;
- return ret < 0 ? ret : security_task_setscheduler(tsk, 0, NULL);
+ return security_task_setscheduler(tsk, 0, NULL);
}
static void cpuset_attach(struct cgroup_subsys *ss,
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
linux-next.patch
oom_kill-dont-call-for-int_sqrt0.patch
page_fault-retry-with-nopage_retry.patch
page_fault-retry-with-nopage_retry-fix.patch
memcg-use-css-id.patch
memcg-hierarchical-stat.patch
memcg-fix-shrinking-memory-to-return-ebusy-by-fixing-retry-algorithm.patch
memcg-fix-oom-killer-under-memcg.patch
memcg-fix-oom-killer-under-memcg-fix2.patch
memcg-fix-oom-killer-under-memcg-fix.patch
memcg-show-memcg-information-during-oom.patch
memcg-show-memcg-information-during-oom-fix2.patch
memcg-show-memcg-information-during-oom-fix.patch
memcg-show-memcg-information-during-oom-fix-fix.patch
memcg-show-memcg-information-during-oom-fix-fix-checkpatch-fixes.patch
cpusets-replace-zone-allowed-functions-with-node-allowed.patch
cpusets-prevent-pf_thread_bound-tasks-from-attaching-to-non-root-cpusets.patch
cpuset-check-if-the-cpus-allowed-is-a-subset-of-the-cpusets-cpus-for-pf_thread_bound-threads.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
