On Fri, Jan 16, 2015 at 11:56 AM, Peter Hurley
<pe...@hurleysoftware.com> wrote:
On 01/06/2015 06:07 AM, Kent Overstreet wrote:
On Tue, Jan 06, 2015 at 12:01:12PM +0100, Peter Zijlstra wrote:
On Tue, Jan 06, 2015 at 11:18:04AM +0100, Sedat Dilek wrote:
On Tue, Jan 6, 2015 at 11:06 AM, Peter Zijlstra
<pet...@infradead.org> wrote:
On Tue, Jan 06, 2015 at 10:57:19AM +0100, Sedat Dilek wrote:
[ 88.028739] [<ffffffff8124433f>] aio_read_events+0x4f/0x2d0
Ah, that one. Chris Mason and Kent Overstreet were looking at
that one.
I'm not touching the AIO code either ;-)
I know, I was so excited when I see nearly the same output.
Can you tell me why people see "similiar" problems in different
areas?
Because the debug check is new :-) It's a pattern that should not
be
used but mostly works most of the times.
[ 181.397024] WARNING: CPU: 0 PID: 2872 at
kernel/sched/core.c:7303
__might_sleep+0xbd/0xd0()
[ 181.397028] do not call blocking ops when !TASK_RUNNING;
state=1
set at [<ffffffff810b83bd>] prepare_to_wait_event+0x5d/0x110
With similiar buzzwords... namely...
mutex_lock_nested
prepare_to_wait(_event)
__might_sleep
I am asking myself... Where is the real root cause - in
sched/core?
Fix one single place VS. fix the impact at several other places?
No, the root cause is nesting sleep primitives, this is not
fixable in
the one place, both prepare_to_wait and mutex_lock are using
task_struct::state, they have to, no way around it.
No, it's completely possible to construct a prepare_to_wait() that
doesn't
require messing with the task state. Had it for years.
https://urldefense.proofpoint.com/v1/url?u=http://evilpiepirate.org/git/linux-bcache.git/log/?h%3Daio_ring_fix&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=6%2FL0lzzDhu0Y1hL9xm%2BQyA%3D%3D%0A&m=QKQw1WQ3qeio%2FM623F%2BN1X1PeHp7PLLjdIQdHnHU5qo%3D%0A&s=b4e94a6a4b0922e356cadd19f6b22862dbd258fa11c2f26c3d7d76dcac1963ce
Peter & Kent,
What's the plan here?
I'm cleaning up my patch slightly and resubmitting.
-chris
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