On Tue, Jan 13, 2015 at 11:06 AM, Benjamin LaHaise <bcrl@xxxxxxxxx>
wrote:
Hi Chris,
On Mon, Dec 22, 2014 at 07:16:25PM -0500, Chris Mason wrote:
The 3.19 merge window brought in a great new warning to catch
someone
calling might_sleep with their state != TASK_RUNNING. The idea was
to
find buggy code locking mutexes after calling prepare_to_wait(),
kind
of like this:
...
This has been lightly tested and hasn't been benchmarked, so RFC for
now.
Signed-off-by: Chris Mason <clm@xxxxxx>
Reported-by: The code of Peter Zijlstra <peterz@xxxxxxxxxxxxx>
After mulling this over, I think your patch is probably the safest
for us
to apply at present as it is also the most amenable to backporting.
Are
you okay with removing the RFC status? I still have my concerns about
possible task wakeups causing problems with filesystem code if the
copy_to_user() takes a page fault, but those can be addressed
separately.
Kent's closures are an option for the future, but I think it would be
more appropriate for that new code to be introduced in the next merge
window.
I'll resend the patch with improved comments, and get perf tests done
on fast storage.
-chris
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