Hi, This is v5 of a series to implement threaded console printing as well as some other minor pieces (such as proc and sysfs recognition of nbcon consoles). v4 is here [0]. For information about the motivation of the nbcon consoles, please read the cover letter of the original v1 [1]. This series provides the remaining pieces of the printk rework. All other components are either already mainline or are currently in linux-next. In particular this series does: - Implement dedicated printing threads per nbcon console. - Implement forced threading of legacy consoles for PREEMPT_RT. - Implement nbcon support for proc and sysfs console-related files. - Provide a new helper function nbcon_reacquire_nobuf() to allow nbcon console drivers to reacquire ownership. Note that this series does *not* provide an nbcon console driver. That will come in a follow-up series. Here are the changes since v4: - For nbcon_kthread_create(), add more explanations about the context and rules to the kerneldoc. - In nbcon_alloc(), clear con->pbufs on failure. - Remove legacy_kthread_wake() and add its functionality to wake_up_klogd_work_func() since it was the only call site. - In console_start(), allow triggering the legacy loop if it is an nbcon. There might be a registered boot console. - In __pr_flush(), add atomic flushing before wait loop. - In console_try_replay_all(), add atomic flushing. John Ogness [0] https://lore.kernel.org/lkml/20240827044333.88596-1-john.ogness@xxxxxxxxxxxxx [1] https://lore.kernel.org/lkml/20230302195618.156940-1-john.ogness@xxxxxxxxxxxxx John Ogness (16): printk: nbcon: Add function for printers to reacquire ownership printk: Fail pr_flush() if before SYSTEM_SCHEDULING printk: Flush console on unregister_console() printk: nbcon: Add context to usable() and emit() printk: nbcon: Init @nbcon_seq to highest possible printk: nbcon: Relocate nbcon_atomic_emit_one() printk: nbcon: Use thread callback if in task context for legacy printk: nbcon: Rely on kthreads for normal operation printk: Provide helper for message prepending printk: nbcon: Show replay message on takeover proc: consoles: Add notation to c_start/c_stop proc: Add nbcon support for /proc/consoles tty: sysfs: Add nbcon support for 'active' printk: Implement legacy printer kthread for PREEMPT_RT printk: nbcon: Assign nice -20 for printing threads printk: Avoid false positive lockdep report for legacy printing Thomas Gleixner (1): printk: nbcon: Introduce printer kthreads drivers/tty/tty_io.c | 2 +- fs/proc/consoles.c | 7 +- include/linux/console.h | 48 +++ kernel/printk/internal.h | 82 ++++- kernel/printk/nbcon.c | 504 +++++++++++++++++++++++++----- kernel/printk/printk.c | 465 ++++++++++++++++++++++++--- kernel/printk/printk_ringbuffer.h | 2 + kernel/printk/printk_safe.c | 4 +- 8 files changed, 981 insertions(+), 133 deletions(-) base-commit: 59cd94ef80094857f0d0085daa2e32badc4cddf4 -- 2.39.2
