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authorTejun Heo <tj@kernel.org>2013-05-10 11:10:17 -0700
committerTejun Heo <tj@kernel.org>2013-05-10 11:10:17 -0700
commitd3251859168b0b12841e1b90d6d768ab478dc23d (patch)
treeccfb1c9c2da7e67d8b9d3ab9a0027a556f0a4fec /kernel
parent2dbd3cac87250a0d44e07acc86c4224a08522709 (diff)
downloadlinux-d3251859168b0b12841e1b90d6d768ab478dc23d.tar.gz
workqueue: workqueue_congested() shouldn't translate WORK_CPU_UNBOUND into node number
df2d5ae499 ("workqueue: map an unbound workqueues to multiple per-node pool_workqueues") made unbound workqueues to map to multiple per-node pool_workqueues and accordingly updated workqueue_contested() so that, for unbound workqueues, it maps the specified @cpu to the NUMA node number to obtain the matching pool_workqueue to query the congested state. Before this change, workqueue_congested() ignored @cpu for unbound workqueues as there was only one pool_workqueue and some users (fscache) called it with WORK_CPU_UNBOUND. After the commit, this causes the following oops as WORK_CPU_UNBOUND gets translated to garbage by cpu_to_node(). BUG: unable to handle kernel paging request at ffff8803598d98b8 IP: [<ffffffff81043b7e>] unbound_pwq_by_node+0xa1/0xfa PGD 2421067 PUD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 2689 Comm: cat Tainted: GF 3.9.0-fsdevel+ #4 task: ffff88003d801040 ti: ffff880025806000 task.ti: ffff880025806000 RIP: 0010:[<ffffffff81043b7e>] [<ffffffff81043b7e>] unbound_pwq_by_node+0xa1/0xfa RSP: 0018:ffff880025807ad8 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff8800388a2400 RCX: 0000000000000003 RDX: ffff880025807fd8 RSI: ffffffff81a31420 RDI: ffff88003d8016e0 RBP: ffff880025807ae8 R08: ffff88003d801730 R09: ffffffffa00b4898 R10: ffffffff81044217 R11: ffff88003d801040 R12: 0000000064206e97 R13: ffff880036059d98 R14: ffff880038cc8080 R15: ffff880038cc82d0 FS: 00007f21afd9c740(0000) GS:ffff88003d100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff8803598d98b8 CR3: 000000003df49000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff8800388a2400 0000000000000002 ffff880025807b18 ffffffff810442ce ffffffff81044217 ffff880000000002 ffff8800371b4080 ffff88003d112ec0 ffff880025807b38 ffffffffa00810b0 ffff880036059d88 ffff880036059be8 Call Trace: [<ffffffff810442ce>] workqueue_congested+0xb7/0x12c [<ffffffffa00810b0>] fscache_enqueue_object+0xb2/0xe8 [fscache] [<ffffffffa007facd>] __fscache_acquire_cookie+0x3b9/0x56c [fscache] [<ffffffffa00ad8fe>] nfs_fscache_set_inode_cookie+0xee/0x132 [nfs] [<ffffffffa009e112>] do_open+0x9/0xd [nfs] [<ffffffff810e804a>] do_dentry_open+0x175/0x24b [<ffffffff810e8298>] finish_open+0x41/0x51 Fix it by using smp_processor_id() if @cpu is WORK_CPU_UNBOUND. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: David Howells <dhowells@redhat.com> Tested-and-Acked-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/workqueue.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4aa9f5bc6b2..1ae602809ef 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4311,6 +4311,12 @@ bool current_is_workqueue_rescuer(void)
* no synchronization around this function and the test result is
* unreliable and only useful as advisory hints or for debugging.
*
+ * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
+ * Note that both per-cpu and unbound workqueues may be associated with
+ * multiple pool_workqueues which have separate congested states. A
+ * workqueue being congested on one CPU doesn't mean the workqueue is also
+ * contested on other CPUs / NUMA nodes.
+ *
* RETURNS:
* %true if congested, %false otherwise.
*/
@@ -4321,6 +4327,9 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
rcu_read_lock_sched();
+ if (cpu == WORK_CPU_UNBOUND)
+ cpu = smp_processor_id();
+
if (!(wq->flags & WQ_UNBOUND))
pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
else