July 10, 2013
Participants: Jan Kara
People tagged: (none)
Jan Kara
would like to discuss his work modifying get_user_pages()
and the page-fault code so that filesystems can drop mmap_sem
in their ->fault and ->page_mkwrite handlers.
He would also like to discuss lockups that are caused by
printk() traffic on systems with slow serial consoles,
where “slow serial consoles” means not only the
glacial 9600-baud consoles (which actually seemed pretty fast
about 30 years ago), but also 115,200-baud consoles, which sometimes
hang on boot due to high printk() rates causing other
interrupts to be lost.
Jan is attempting to find a solution, but has come up empty after
several tries, one of which involved the new irq_work()
facility (which unfortunately did not reduce the amount of time
that the victim CPU's interrupts were disabled, thus not helping).