diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0031-printk-nbcon-Introduce-printing-kthreads.patch (renamed from debian/patches-rt/0030-printk-nbcon-Introduce-printing-kthreads.patch) | 77 |
1 files changed, 40 insertions, 37 deletions
diff --git a/debian/patches-rt/0030-printk-nbcon-Introduce-printing-kthreads.patch b/debian/patches-rt/0031-printk-nbcon-Introduce-printing-kthreads.patch index 85792a75e2..8557ac1ea9 100644 --- a/debian/patches-rt/0030-printk-nbcon-Introduce-printing-kthreads.patch +++ b/debian/patches-rt/0031-printk-nbcon-Introduce-printing-kthreads.patch @@ -1,7 +1,7 @@ From: Thomas Gleixner <tglx@linutronix.de> Date: Fri, 22 Sep 2023 14:12:21 +0000 -Subject: [PATCH 30/46] printk: nbcon: Introduce printing kthreads -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.9/older/patches-6.9-rt5.tar.xz +Subject: [PATCH 31/48] printk: nbcon: Introduce printing kthreads +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz Provide the main implementation for running a printer kthread per nbcon console that is takeover/handover aware. @@ -14,8 +14,8 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> include/linux/console.h | 26 ++++++ kernel/printk/internal.h | 26 ++++++ kernel/printk/nbcon.c | 196 +++++++++++++++++++++++++++++++++++++++++++++-- - kernel/printk/printk.c | 31 +++++++ - 4 files changed, 271 insertions(+), 8 deletions(-) + kernel/printk/printk.c | 34 ++++++++ + 4 files changed, 275 insertions(+), 7 deletions(-) --- a/include/linux/console.h +++ b/include/linux/console.h @@ -29,7 +29,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> @@ -324,6 +325,8 @@ struct nbcon_write_context { * @nbcon_seq: Sequence number of the next record for nbcon to print - * @nbcon_driver_ctxt: Context available for driver non-printing operations + * @nbcon_device_ctxt: Context available for non-printing operations * @pbufs: Pointer to nbcon private buffer + * @kthread: Printer kthread for this console + * @rcuwait: RCU-safe wait object for @kthread waking @@ -42,11 +42,11 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> /** + * @write_thread: + * -+ * NBCON callback to write out text in task context. (Optional) ++ * NBCON callback to write out text in task context. + * -+ * This callback is called with the console already acquired. Any -+ * additional driver synchronization should have been performed by -+ * device_lock(). ++ * This callback is called after device_lock() and with the nbcon ++ * console acquired. Any necessary driver synchronization should have ++ * been performed by the device_lock() callback. + * + * This callback is always called from task context but with migration + * disabled. @@ -55,8 +55,8 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + * sections applies as with write_atomic(). The difference between + * this callback and write_atomic() is that this callback is used + * during normal operation and is always called from task context. -+ * This provides drivers with a relatively relaxed locking context -+ * for synchronizing output to the hardware. ++ * This allows drivers to operate in their own locking context for ++ * synchronizing output to the hardware. + */ + void (*write_thread)(struct console *con, struct nbcon_write_context *wctxt); + @@ -66,7 +66,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> * NBCON callback to begin synchronization with driver code. @@ -420,6 +444,8 @@ struct console { atomic_long_t __private nbcon_seq; - struct nbcon_context __private nbcon_driver_ctxt; + struct nbcon_context __private nbcon_device_ctxt; struct printk_buffers *pbufs; + struct task_struct *kthread; + struct rcuwait rcuwait; @@ -75,7 +75,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> #ifdef CONFIG_LOCKDEP --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h -@@ -90,6 +90,7 @@ enum nbcon_prio nbcon_get_default_prio(v +@@ -92,6 +92,7 @@ enum nbcon_prio nbcon_get_default_prio(v void nbcon_atomic_flush_pending(void); bool nbcon_legacy_emit_next_record(struct console *con, bool *handover, int cookie); @@ -83,7 +83,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> /* * Check if the given console is currently capable and allowed to print -@@ -108,6 +109,8 @@ static inline bool console_is_usable(str +@@ -110,6 +111,8 @@ static inline bool console_is_usable(str if (flags & CON_NBCON) { if (!con->write_atomic) return false; @@ -92,7 +92,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> } else { if (!con->write) return false; -@@ -124,12 +127,35 @@ static inline bool console_is_usable(str +@@ -126,12 +129,35 @@ static inline bool console_is_usable(str return true; } @@ -142,7 +142,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> /** * nbcon_emit_next_record - Emit a record in the acquired context * @wctxt: The write context that will be handed to the write function -+ * @use_atomic: True if the write_atomic callback is to be used ++ * @use_atomic: True if the write_atomic() callback is to be used * * Return: True if this context still owns the console. False if * ownership was handed over or taken. @@ -171,15 +171,14 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> } else { /* * This function should never be called for legacy consoles. -@@ -936,6 +944,118 @@ static bool nbcon_emit_next_record(struc +@@ -936,6 +944,120 @@ static bool nbcon_emit_next_record(struc return nbcon_context_exit_unsafe(ctxt); } +/** + * nbcon_kthread_should_wakeup - Check whether a printer thread should wakeup + * @con: Console to operate on -+ * @ctxt: The acquire context that contains the state -+ * at console_acquire() ++ * @ctxt: The nbcon context from nbcon_context_try_acquire() + * + * Return: True if the thread should shutdown or if the console is + * allowed to print and a record is available. False otherwise. @@ -213,6 +212,8 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +/** + * nbcon_kthread_func - The printer thread function + * @__console: Console to operate on ++ * ++ * Return: 0 + */ +static int nbcon_kthread_func(void *__console) +{ @@ -222,7 +223,6 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + .ctxt.prio = NBCON_PRIO_NORMAL, + }; + struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); -+ unsigned long flags; + short con_flags; + bool backlog; + int cookie; @@ -258,7 +258,9 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + con_flags = console_srcu_read_flags(con); + + if (console_is_usable(con, con_flags)) { -+ con->device_lock(con, &flags); ++ unsigned long lock_flags; ++ ++ con->device_lock(con, &lock_flags); + + /* + * Ensure this stays on the CPU to make handover and @@ -277,7 +279,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + } + } + -+ con->device_unlock(con, flags); ++ con->device_unlock(con, lock_flags); + } + + console_srcu_read_unlock(cookie); @@ -290,7 +292,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> /* Track the nbcon emergency nesting per CPU. */ static DEFINE_PER_CPU(unsigned int, nbcon_pcpu_emergency_nesting); static unsigned int early_nbcon_pcpu_emergency_nesting __initdata; -@@ -1012,7 +1132,7 @@ static bool nbcon_atomic_emit_one(struct +@@ -1012,7 +1134,7 @@ static bool nbcon_atomic_emit_one(struct * The higher priority printing context takes over responsibility * to print the pending records. */ @@ -299,7 +301,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> return false; nbcon_context_release(ctxt); -@@ -1113,7 +1233,7 @@ static int __nbcon_atomic_flush_pending_ +@@ -1113,7 +1235,7 @@ static int __nbcon_atomic_flush_pending_ * handed over or taken over. In both cases the context is no * longer valid. */ @@ -308,23 +310,21 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> return -EAGAIN; if (!ctxt->backlog) { -@@ -1159,11 +1279,11 @@ static void nbcon_atomic_flush_pending_c - local_irq_restore(flags); +@@ -1172,10 +1294,10 @@ static void nbcon_atomic_flush_pending_c /* -- * If flushing was successful but more records are available, this + * If flushing was successful but more records are available, this - * context must flush those remaining records because there is no - * other context that will do it. -+ * If flushing was successful but more records are available this + * context must flush those remaining records if the printer thread -+ * is not available to do it. ++ * is not available do it. */ -- if (!err && prb_read_valid(prb, nbcon_seq_read(con), NULL)) { -+ if (!err && !con->kthread && prb_read_valid(prb, nbcon_seq_read(con), NULL)) { +- if (prb_read_valid(prb, nbcon_seq_read(con), NULL)) { ++ if (!con->kthread && prb_read_valid(prb, nbcon_seq_read(con), NULL)) { stop_seq = prb_next_reserve_seq(prb); goto again; } -@@ -1315,6 +1435,63 @@ void nbcon_cpu_emergency_flush(void) +@@ -1332,6 +1454,63 @@ void nbcon_cpu_emergency_flush(void) } } @@ -388,7 +388,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> /** * nbcon_alloc - Allocate buffers needed by the nbcon console * @con: Console to allocate buffers for -@@ -1360,6 +1537,7 @@ void nbcon_init(struct console *con, u64 +@@ -1377,6 +1556,7 @@ void nbcon_init(struct console *con, u64 /* nbcon_alloc() must have been called and successful! */ BUG_ON(!con->pbufs); @@ -396,7 +396,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> nbcon_seq_force(con, init_seq); nbcon_state_set(con, &state); } -@@ -1372,6 +1550,7 @@ void nbcon_free(struct console *con) +@@ -1389,6 +1569,7 @@ void nbcon_free(struct console *con) { struct nbcon_state state = { }; @@ -404,7 +404,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> nbcon_state_set(con, &state); /* Boot consoles share global printk buffers. */ -@@ -1440,6 +1619,7 @@ void nbcon_driver_release(struct console +@@ -1458,6 +1639,7 @@ void nbcon_device_release(struct console */ cookie = console_srcu_read_lock(); if (console_is_usable(con, console_srcu_read_flags(con)) && @@ -452,15 +452,15 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> if (!console_is_usable(con, flags)) continue; any_usable = true; -@@ -3314,9 +3331,23 @@ EXPORT_SYMBOL(console_stop); +@@ -3326,9 +3343,26 @@ EXPORT_SYMBOL(console_stop); void console_start(struct console *console) { + short flags; ++ int cookie; + console_list_lock(); console_srcu_write_flags(console, console->flags | CON_ENABLED); -+ flags = console->flags; console_list_unlock(); + + /* @@ -470,8 +470,11 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> + */ + synchronize_srcu(&console_srcu); + ++ cookie = console_srcu_read_lock(); ++ flags = console_srcu_read_flags(console); + if (flags & CON_NBCON) + nbcon_kthread_wake(console); ++ console_srcu_read_unlock(cookie); + __pr_flush(console, 1000, true); } |