From 1474fccd2fb1cf6ccd14979a3b5405d2a355054b Mon Sep 17 00:00:00 2001 From: Jeff Epler Date: Mon, 11 May 2020 08:37:20 -0500 Subject: [PATCH] supervisor: Add a linked list of background callbacks In time, we should transition interrupt driven background tasks out of the overall run_background_tasks into distinct background callbacks, so that the number of checks that occur with each tick is reduced. --- main.c | 3 + supervisor/background_callback.h | 82 +++++++++++++++++++ supervisor/shared/background_callback.c | 104 ++++++++++++++++++++++++ supervisor/shared/tick.c | 6 +- supervisor/supervisor.mk | 1 + 5 files changed, 192 insertions(+), 4 deletions(-) create mode 100644 supervisor/background_callback.h create mode 100644 supervisor/shared/background_callback.c diff --git a/main.c b/main.c index c3787122d3..201022f1af 100755 --- a/main.c +++ b/main.c @@ -45,6 +45,7 @@ #include "background.h" #include "mpconfigboard.h" +#include "supervisor/background_callback.h" #include "supervisor/cpu.h" #include "supervisor/memory.h" #include "supervisor/port.h" @@ -161,6 +162,8 @@ void stop_mp(void) { MP_STATE_VM(vfs_cur) = vfs; #endif + background_callback_reset(); + gc_deinit(); } diff --git a/supervisor/background_callback.h b/supervisor/background_callback.h new file mode 100644 index 0000000000..82025f6b7a --- /dev/null +++ b/supervisor/background_callback.h @@ -0,0 +1,82 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2020 Jeff Epler for Adafruit Industries + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#ifndef CIRCUITPY_INCLUDED_SUPERVISOR_BACKGROUND_CALLBACK_H +#define CIRCUITPY_INCLUDED_SUPERVISOR_BACKGROUND_CALLBACK_H + +/** Background callbacks are a linked list of tasks to call in the background. + * + * Include a member of type `background_callback_t` inside an object + * which needs to queue up background work, and zero-initialize it. + * + * To schedule the work, use background_callback_add, with fun as the + * function to call and data pointing to the object itself. + * + * Next time run_background_tasks_if_tick is called, the callback will + * be run and removed from the linked list. + * + * Queueing a task that is already queued does nothing. Unconditionally + * re-queueing it from its own background task will cause it to run during the + * very next background-tasks invocation, leading to a CircuitPython freeze, so + * don't do that. + * + * background_callback_add can be called from interrupt context. + */ +typedef void (*background_callback_fun)(void *data); +typedef struct background_callback { + background_callback_fun fun; + void *data; + struct background_callback *next; + struct background_callback *prev; +} background_callback_t; + +/* Add a background callback for which 'fun' and 'data' were previously set */ +void background_callback_add_core(background_callback_t *cb); + +/* Add a background callback to the given function with the given data. When + * the callback involves an object on the GC heap, the 'data' must be a pointer + * to that object itself, not an internal pointer. Otherwise, it can be the + * case that no other references to the object itself survive, and the object + * becomes garbage collected while an outstanding background callback still + * exists. + */ +void background_callback_add(background_callback_t *cb, background_callback_fun fun, void *data); + +/* Run all background callbacks. Normally, this is done by the supervisor + * whenever the list is non-empty */ +void background_callback_run_all(void); + +/* During soft reset, remove all pending callbacks and clear the critical section flag */ +void background_callback_reset(void); + +/* Sometimes background callbacks must be blocked. Use these functions to + * bracket the section of code where this is the case. These calls nest, and + * begins must be balanced with ends. + */ +void background_callback_begin_critical_section(void); +void background_callback_end_critical_section(void); + +#endif diff --git a/supervisor/shared/background_callback.c b/supervisor/shared/background_callback.c new file mode 100644 index 0000000000..99607b7a85 --- /dev/null +++ b/supervisor/shared/background_callback.c @@ -0,0 +1,104 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2020 Jeff Epler for Adafruit Industries + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "py/mpconfig.h" +#include "supervisor/background_callback.h" +#include "supervisor/shared/tick.h" +#include "shared-bindings/microcontroller/__init__.h" + +STATIC volatile background_callback_t *callback_head, *callback_tail; + +#define CALLBACK_CRITICAL_BEGIN (common_hal_mcu_disable_interrupts()) +#define CALLBACK_CRITICAL_END (common_hal_mcu_enable_interrupts()) + +void background_callback_add_core(background_callback_t *cb) { + CALLBACK_CRITICAL_BEGIN; + if (cb->prev || callback_head == cb) { + CALLBACK_CRITICAL_END; + return; + } + cb->next = 0; + cb->prev = (background_callback_t*)callback_tail; + if (callback_tail) { + callback_tail->next = cb; + cb->prev = (background_callback_t*)callback_tail; + } + if (!callback_head) { + callback_head = cb; + } + callback_tail = cb; + CALLBACK_CRITICAL_END; +} + +void background_callback_add(background_callback_t *cb, background_callback_fun fun, void *data) { + cb->fun = fun; + cb->data = data; + background_callback_add_core(cb); +} + +static bool in_background_callback; +void background_callback_run_all() { + CALLBACK_CRITICAL_BEGIN; + if(in_background_callback) { + CALLBACK_CRITICAL_END; + return; + } + in_background_callback = true; + background_callback_t *cb = (background_callback_t*)callback_head; + callback_head = NULL; + callback_tail = NULL; + while (cb) { + background_callback_t *next = cb->next; + cb->next = cb->prev = NULL; + background_callback_fun fun = cb->fun; + void *data = cb->data; + CALLBACK_CRITICAL_END; + // Leave the critical section in order to run the callback function + if (fun) { + fun(data); + } + CALLBACK_CRITICAL_BEGIN; + cb = next; + } + in_background_callback = false; + CALLBACK_CRITICAL_END; +} + +void background_callback_begin_critical_section() { + CALLBACK_CRITICAL_BEGIN; +} + +void background_callback_end_critical_section() { + CALLBACK_CRITICAL_END; +} + +void background_callback_reset() { + CALLBACK_CRITICAL_BEGIN; + callback_head = NULL; + callback_tail = NULL; + in_background_callback = false; + CALLBACK_CRITICAL_END; +} diff --git a/supervisor/shared/tick.c b/supervisor/shared/tick.c index 01a554e156..7a2f313eb8 100644 --- a/supervisor/shared/tick.c +++ b/supervisor/shared/tick.c @@ -29,6 +29,7 @@ #include "py/mpstate.h" #include "supervisor/linker.h" #include "supervisor/filesystem.h" +#include "supervisor/background_callback.h" #include "supervisor/port.h" #include "supervisor/shared/autoreload.h" @@ -86,10 +87,7 @@ uint32_t supervisor_ticks_ms32() { extern void run_background_tasks(void); void PLACE_IN_ITCM(supervisor_run_background_tasks_if_tick)() { - // TODO: Add a global that can be set by anyone to indicate we should run background tasks. That - // way we can short circuit the background tasks early. We used to do it based on time but it - // breaks cases where we wake up for a short period and then sleep. If we skipped the last - // background task or more before sleeping we may end up starving a task like USB. + background_callback_run_all(); run_background_tasks(); } diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk index 21803ae0a3..1885366865 100644 --- a/supervisor/supervisor.mk +++ b/supervisor/supervisor.mk @@ -2,6 +2,7 @@ SRC_SUPERVISOR = \ main.c \ supervisor/port.c \ supervisor/shared/autoreload.c \ + supervisor/shared/background_callback.c \ supervisor/shared/board.c \ supervisor/shared/filesystem.c \ supervisor/shared/flash.c \