Messages in this thread | | | From | John Ogness <> | Subject | [PATCH printk v3 0/7] provide nbcon base | Date | Sun, 3 Sep 2023 17:11:32 +0206 |
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Hi,
This is v3 of a series to introduce the new non-BKL (nbcon) consoles. v2 is here [0]. For information about the motivation of the atomic consoles, please read the cover letter of v1 [1].
This series focuses on providing the base functionality of the nbcon consoles. In particular, it implements the ownership and priority semantics for nbcon consoles. This series does _not_ include threaded printing, atomic printing regions, or nbcon drivers. Those features will be added in separate follow-up series.
The changes since v2:
- rename nbcon_state::hostile_unsafe to nbcon_state::unsafe_takeover
- add 2-bit nbcon_state::req_tag to help identify waiters
- remove nbcon_context::unsafe
- remove nbcon_context::hostile
- rename nbcon_context::takeover_unsafe to nbcon_context::allow_unsafe_takeover
- callers must now check the current console state to see if it acquired the console using the unsafe hostile takeover method
- rename nbcon_write_context::hostile_unsafe to nbcon_write_context::unsafe_takeover
- allow direct takeover of owned consoles if higher priority and safe
- rename printk_nbcon.c to nbcon.c
- remove most printk.c changes, to be added in a later series once all the nbcon functionality is implemented (only init and seq updates/checks are kept)
- add nbcon_alloc() to be called early in register_console() to allow for simple backout on failure (nbcon_init() changed to return void)
- remove my special debugging because it was annoying
- rename __nbcon_seq_to_stored() to __seq_to_nbcon_seq()
- rename __nbcon_seq_to_full() to __nbcon_seq_to_seq()
- implement seq translation as suggested by pmladek
- in nbcon_seq_try_update(), unconditionally attempt cmpxchg to allow CONSOLE_REPLAY_ALL to work
- change semantics of all acquire methods to simplify the model
- add nbcon_waiter_matches() to check waiter based on prio and req_tag
- add nbcon_context_try_acquire_requested() to implement handover part of acquiring after setting request
- in nbcon_context_update_unsafe(), perform handover when transitioning to !unsafe and there is a waiter
- in nbcon_emit_next_record(), simplify initializing @wctxt
- in nbcon_emit_next_record(), set the console state to unsafe while updating @dropped and @nbcon_seq to avoid data race when not in panic
- cleanup comments as suggested by pmladek
John Ogness
[0] https://lore.kernel.org/lkml/20230728000233.50887-1-john.ogness@linutronix.de
[1] https://lore.kernel.org/lkml/20230302195618.156940-6-john.ogness@linutronix.de
Thomas Gleixner (7): printk: Add non-BKL (nbcon) console basic infrastructure printk: nbcon: Add acquire/release logic printk: nbcon: Add buffer management printk: nbcon: Add ownership state functions printk: nbcon: Add sequence handling printk: nbcon: Add emit function and callback function for atomic printing printk: nbcon: Add functions for drivers to mark unsafe regions
include/linux/console.h | 135 ++++++ kernel/printk/Makefile | 2 +- kernel/printk/internal.h | 29 ++ kernel/printk/nbcon.c | 945 +++++++++++++++++++++++++++++++++++++++ kernel/printk/printk.c | 60 ++- 5 files changed, 1152 insertions(+), 19 deletions(-) create mode 100644 kernel/printk/nbcon.c
base-commit: cb65d08d735e00cc55ad7700a82a453bb88c93a3 -- 2.39.2
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